TEAM 14 -HAZMAT ROBOT FINAL REPORT

EML 4905 Senior Design Project

A B.S. THESIS

PREPARED IN PARTIAL FULFILLMENT OF THE

REQUIREMENT FOR THE DEGREE OF

BACHELOR OF SCIENCE

IN

MECHANICAL ENGINEERING

HAZMAT SAFETY AND

RECONNAISSANCE UNIT

FINAL REPORT

Daniel Pico

Christian Palomo

Samuel Caillouette

Advisor: Professor Sabri Tosunoglu

November 20, 2015

This B.S. thesis is written in partial fulfillment of the requirements in EML 4905.

The contents represent the opinion of the authors and not the Department of

Mechanical and Materials Engineering.

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Ethics Statement and Signatures

The work submitted in this B.S. thesis is solely prepared by a team consisting of Daniel Pico,

Christian Palomo, and Samuel Callouette and it is original. Excerpts from others’ work have

been clearly identified, their work acknowledged within the text and listed in the list of

references. All of the engineering drawings, computer programs, formulations, design work,

prototype development and testing reported in this document are also original and prepared by

the same team of students.

Daniel Pico

Team Leader

Christian Palomo

Team Member

Samuel Caillouette

Team Member

Dr. Sabri Tosunoglu

Faculty Advisor

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TABLE OF CONTENTS Chapter Page

Abstract ...................................................................................................................................... 1

1. Introduction .......................................................................................................................... 1

1.1. Problem Statement ........................................................................................................... 1

1.2. Motivation ........................................................................................................................ 2

1.3. Literature Survey .............................................................................................................. 3

1.4. Survey of Related Standards ............................................................................................ 8

2. Project Formulation ........................................................................................................... 11

2.1. Overview ........................................................................................................................ 11

2.2. Project Objectives .......................................................................................................... 11

2.3. Design Specification ...................................................................................................... 12

2.4. Addressing Global Design ............................................................................................. 14

2.5. Constraints and Other Considerations ............................................................................ 16

3. Design Alternatives ............................................................................................................ 18

3.1. Overview of Conceptual Designs Developed ................................................................ 18

3.2. Design Alternate 1 .......................................................................................................... 19



3.5. Feasibility Assessment ................................................................................................... 25

3.6. Proposed Design ............................................................................................................. 26

3.7. Discussion ...................................................................................................................... 27

4. Project Management .......................................................................................................... 27

4.1. Overview ........................................................................................................................ 27

4.2. Breakdown of Work into Specific Tasks ....................................................................... 27

4.3. Breakdown of Responsibilities Among Team Members ............................................... 29

4.4. Patent/ Copyright Application ........................................................................................ 31

4.5. Commercialization of the Final Product ........................................................................ 31

4.6. Discussion ...................................................................................................................... 31

5. Engineering Design and Analysis ...................................................................................... 31

5.1. Overview ........................................................................................................................ 31

5.2. Kinematic Analysis ........................................................................................................ 32

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5.3. Stress Analysis ............................................................................................................... 35

5.4. Mechanical Analysis ...................................................................................................... 35

5.5. Material Selections ......................................................................................................... 39

5.6. Finite Element Analysis ................................................................................................. 42

5.7. Motor analysis and selection: ......................................................................................... 44

5.8. Battery Selection ............................................................................................................ 47

5.9. Communication system .................................................................................................. 53

5.10. Speed Controllers ....................................................................................................... 57

5.11. Camera ........................................................................................................................ 60

5.12. Electrical Circuit ......................................................................................................... 62

5.13. Proposed Drive Train Cost Summery ......................................................................... 65

6. Prototype Construction ...................................................................................................... 66

6.1. Overview ........................................................................................................................ 66

6.2. Description of Prototype ................................................................................................ 66

6.3. Prototype Design ............................................................................................................ 67

6.4. Parts List ......................................................................................................................... 69

6.5. Construction ................................................................................................................... 70

7. Testing and Evaluation ...................................................................................................... 89

7.1. Testing and Evaluation ................................................................................................... 89

7.2. Design of Experiments – Description of Experiments ................................................... 89

7.3. Towing Test.................................................................................................................... 90

7.4. Battery Consumption Test .............................................................................................. 92

7.5. Speed Test ...................................................................................................................... 93

7.6. Stair Climbing Test ........................................................................................................ 94

7.7. Improvement of Design:................................................................................................. 97

7.8. Discussion: ..................................................................................................................... 98

8. Design considerations ........................................................................................................ 98

8.1. Health and Safety ........................................................................................................... 98

8.2. Assembly and Disassembly .......................................................................................... 101

8.3. Manufacturability ......................................................................................................... 104

8.4. Maintenance of the System .......................................................................................... 104

8.5. Risk Assessment ........................................................................................................... 105

9. Design Experience ........................................................................................................... 106

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9.1. Overview ...................................................................................................................... 106

9.2. Standards used on the project ....................................................................................... 107

9.3. The contemporary issues .............................................................................................. 108

9.4. The Impact of the design in a global and societal context ........................................... 109

9.5. Professional and Ethical Responsibility ....................................................................... 109

9.6. Life-Long Learning Experience ................................................................................... 110

9.7. Discussion .................................................................................................................... 111

10. Conclusion ....................................................................................................................... 111

10.1. Conclusion and Discussion ....................................................................................... 111

10.2. Evaluation of Integrated Global Design Aspects ..................................................... 115

10.3. Evaluation of Intangible Experiences ....................................................................... 116

10.4. Commercialization Prospects of the Product ............................................................ 120

10.5. Future Work .............................................................................................................. 121

11. References ........................................................................................................................ 124

Appendices ............................................................................................................................. 128

A. Detailed Engineering Drawings of All Parts, Subsystems and Assemblies ...... 128

B. Multilingual User’s Manuals in English, Spanish and French .......................... 147

C. Excerpts of Guidelines Used in the Project: Standards, Codes, Specifications and

Technical Regulations .................................................................................................. 154

D. Copies of Used Commercial Machine Element Catalogs (Scanned Material) . 155

E. Detailed Raw Design Calculations and Analysis (Scanned Material) .................. 166

F. Project Photo Album ............................................................................................. 182

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List of Figures

Figure 1: Proposed Drivetrain ....................................................................................................... 19 Figure 2: Jaws of Life ................................................................................................................... 20 Figure 3: Complete assembly........................................................................................................ 21 Figure 4: Exploded Assembly- ..................................................................................................... 22

Figure 5: Drive is stopped, free body diagram of robot static situation ....................................... 33 Figure 6: Net weight of 1/3 scale robot and corresponding static torque ..................................... 33 Figure 7: Dynamic model, drive is in motion climbing ................................................................ 34 Figure 8: Gear System .................................................................................................................. 35 Figure 9: Bearing Free Body Diagram.......................................................................................... 37

Figure 10: Related nomenclature and application conversion factor............................................ 37

Figure 11: Simulation of tread track using POM Acetyl Copolymer ........................................ 42

Figure 12: Stainless Steel Chain link ........................................................................................... 42

Figure 13: Panel without Pocket ................................................................................................. 43

Figure 14: example of panel with pocket ................................................................................... 43 Figure 15: MMP-TM57 Geared Motor [21] ................................................................................. 46 Figure 16: MMP-TM55 Geared Motor ......................................................................................... 46 Figure 17: Amp flow E30-400 Motor [22] ................................................................................... 47

Figure 18: Drive Motor Current Draw .......................................................................................... 48 Figure 19: Parallel vs. Series configurations [23] ......................................................................... 50

Figure 20: Power Sonic PSH-1280f2 [24] .................................................................................... 51 Figure 21: Performance Specifications for PSH-1280F2 Battery [25] ......................................... 52 Figure 22: Arduino Mega [26] ...................................................................................................... 53

Figure 23: Raspberry Pi [27]......................................................................................................... 55

Figure 24: Vex microcontroller brain, Controller, Receiver [28] ................................................. 56 Figure 25: Code applied for tank drive onto robot ....................................................................... 57 Figure 26: Comparison of Vex Motor Controllers [29] ................................................................ 58

Figure 27: Victor SP Interface Dimensions [28] .......................................................................... 59 Figure 28: D-Link 931L ip Camera [30]....................................................................................... 60

Figure 29: Example Circuit Diagram for Voltage Regulator [31] ................................................ 62

Figure 30: Circuit Diagram of Prototype Robot ........................................................................... 64 Figure 31: Prototype Model of the HAZMAT ROBOT ............................................................... 68

Figure 32: Installing each of the support blocks for each side ..................................................... 72 Figure 33: Setting up each of the steps ......................................................................................... 72 Figure 34: Completed stairs and assembly not including table .................................................... 73

Figure 35: Completed stairs and table front view ......................................................................... 73 Figure 36: Completed stairs Isometric view ................................................................................. 74

Figure 37: Water Jetting Facility .................................................................................................. 75 Figure 38: Inner and outer plate’s appearance after Water Jetting ............................................... 76 Figure 39 (Fadel CNC Milling Machine [32] ............................................................................... 77 Figure 40: Flat end mill used for CNC manufacturing [33] ......................................................... 77 Figure 41: Appearance of Inner and Outer Panels after CNC operation ...................................... 78

Figure 42: Appearance of Motor Receivers after CNC operation ................................................ 78 Figure 43: Knee Mill on the left side Drill press on the right Side ............................................... 80 Figure 44: Knee Mill Machining features on sprocket ................................................................. 81

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Figure 45: Lathe used to create holes and create press fit ............................................................ 81

Figure 46: Reamer tools used to create press fit ........................................................................... 82 Figure 47: Vertical Band Saw [35] ............................................................................................... 82 Figure 48: Horizontal Band Saw [36] ........................................................................................... 83

Figure 49: Bench Grinder [37] ...................................................................................................... 83 Figure 50: Tread Jig ...................................................................................................................... 85 Figure 51: Tread Chain K-1 Tabs ................................................................................................. 85 Figure 52: Chassis of Robot not including bottom and battery housing plates ............................ 86 Figure 53: Chassis of robot including bottom battery housing plates .......................................... 86

Figure 54: Final assembly with batteries and additional components except the suspension ...... 87 Figure 55: Assembly without motors and tread system) .............................................................. 87 Figure 56: Final side assembly without outer panel ..................................................................... 88 Figure 57: Complete assembly of Hazmat Reconnaissance Robot .............................................. 88

Figure 58: 60.5lb. Cinder block on Concrete ................................................................................ 91 Figure 59: 36.5 lb. Cinder Block on Concrete .............................................................................. 92

Figure 60: Distance of weight relative to center of Mass ............................................................. 95 Figure 61: 5lb. counter weight ...................................................................................................... 96

Figure 62: 10lb. counter weight .................................................................................................... 96 Figure 63: 12 lb. counter weight ................................................................................................... 97 Figure 64: Left Fuse that has been popped, Right Fuse in good condition [41] ......................... 100

Figure 65: Illustration of removal of side panel for tread maintenance ...................................... 101 Figure 66: result of removing side panel and tread system ........................................................ 102

Figure 67: Wing Nut [42] .......................................................................................................... 103 Figure 68: Latch [43] .................................................................................................................. 103 Figure 69: Hairpin Cotter Pin [44] .............................................................................................. 103

Figure 70: Shelf life of Selected Battery Power Sonic PSH-1280 [25] ...................................... 105

Figure 71: Force hand calculation page 1 ................................................................................... 166 Figure 72: Force hand Calculation Page 2 .................................................................................. 166 Figure 73: Force hand Calculation Page 3 .................................................................................. 167

Figure 74: Suspension designs .................................................................................................... 167 Figure 75: Suspension Hand Calculation Page 1 ........................................................................ 168

Figure 76: Static Suspension Hand Calculation Page ................................................................. 168 Figure 77: Bearing Free Body Diagram...................................................................................... 169

Figure 78: Static analysis of robot on incline ............................................................................. 170 Figure 79: Dynamic analysis of robot on incline ........................................................................ 171 Figure 80: Analysis of robot climbing stairs............................................................................... 172 Figure 81: Minimum power requirement for stair climbing ....................................................... 173 Figure 82: Motor comparison for full size design ...................................................................... 174

Figure 83: Battery and stair sample hand calculations ............................................................... 175 Figure 84: Stair Construction Calculations ................................................................................. 176

Figure 85: component dimensions Page 1 .................................................................................. 177 Figure 86: Component Dimensions Page 2 ................................................................................ 178 Figure 87: Component Dimensions Page 3 ................................................................................ 179 Figure 88: Machinability component Mach set up ..................................................................... 180 Figure 89: component suspension dimensions ........................................................................... 181

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List of Tables

Table 1: Breakdown of work into specific tasks ........................................................................... 28 Table 2: Timeline of Project ......................................................................................................... 29 Table 3: Breakdown of Responsibilities among Team Members ................................................. 30 Table 4: Nomenclature for Kinematic Diagram and Equations for Static and Dynamic Analysis

....................................................................................................................................................... 32 Table 5: Weibull Parameters ......................................................................................................... 38 Table 6: Material Selection Properties for common metal grades ................................................ 40 Table 7: Projected Weight Analysis and Torque by considering varying degrees of incline ....... 44 Table 8: Power Requirement when submitted to a 70 degree incline........................................... 45

Table 9: Motors considered for selection ...................................................................................... 47 Table 10: Items in circuit .............................................................................................................. 63

Table 11: Cost Breakdown............................................................................................................ 65 Table 12: Part List for Robot ........................................................................................................ 69 Table 13: Nomenclature used for construction ............................................................................. 70 Table 14: Towing Test Results ..................................................................................................... 91

Table 15: Battery Consumption Test ............................................................................................ 93 Table 16: Speed Test Results ........................................................................................................ 94 Table 17: Stair Climbing Test ....................................................................................................... 95

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Abstract

The following information and data describe a unique robotics platform devised for the

purpose of assisting HAZMAT personnel with the preliminary investigation of a scene. The

apparatus features a tank-style chassis, a four degree-of-freedom arm, the Jaws of Life, and a

modular clamping system for the attachment of various sensors. This robotics platform

represents a different approach to the application of robotics to first responder applications.

1. Introduction

1.1. Problem Statement

HAZMAT Firemen and women risk their lives when they enter a contaminated scene. The

current method of controlling a HAZMAT scene involves manually inspecting the scene and

establishing a perimeter. Once the perimeter is controlled, HAZMAT crews will put on the

required protective gear and move into the scene, using hand-held tools and an array of sensors

to investigate the scene. Some of those tools or devices can be cumbersome for the user when

wearing HAZMAT suit. In addition to the awkward shape and bulk of the suit, HAZMAT

personnel have a very limited amount of time active on the scene because of the limitations of

their air supply. This air supply is further shortened because of the time delay for preparations

before entering the scene and decontamination after exiting the scene. Finally, while time is

passing, conditions of the scene could worsen and potentially endanger the HAZMAT personnel

as well as the general public. It is important for HAZMAT personnel to contain and resolve the

scene as quickly and smoothly as possible.

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1.2. Motivation

For many years, companies such as NASA and Northrop Grumman have developed robotic

ROV platforms (Remote Operated Vehicle) for the military, police and other First Responder

applications. In the current robotics industry there are also a number of smaller companies that

focus solely on robotics. Some of these companies have boasted that their platforms will one day

perform the role of human first responders, capable of transport and rendering aid to the victim.

While projects like these have pure motives, they fall short in practicality and utility.

Furthermore, the platforms that have been successful, such as EOD and surveillance type

platforms still have inadequacies. Either the platform is so small and convenient to use that it

cannot withstand abuse or perform key tasks, or it is capable of performing a task and is

awkward in build and can become incapacitated relatively easy.

The field of HAZMAT Firefighting could benefit greatly from the implementation of

robotics platforms but the requirements are strenuous and varied. HAZMAT (Hazardous

Materials) is a term that pertains to the containment and disposal protocols of chemicals.

HAZMAT Firefighters are certified as firefighters first and then take on additional training to

become HAZMAT certified. While in the line of duty, these brave men and women risk

exposure to dangerous chemicals and are only protected by wearing special suits, which isolate

them and their air supply from the environment.

There are several disadvantages with this approach; the suit is large and limits the flexibility

of the wearer, and if the suit should become torn, there is an additional risk of being exposed to

contaminants, which can result in serious injury or death. Lastly, assuming the firefighters

investigated the scene and have identified what the chemicals are present, they have to exit the

scene, be decontaminated, and then have the suit removed and disposed of. This process could

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take at least 30 minutes, or it can take several hours depending on circumstances. If HAZMAT

Firefighters could investigate the scene and prepare for addressing the problem simultaneously, it

would reduce the overall time on scene and thereby limit the exposure of the firefighters and the

general public. This can be accomplished by creating a robotics platform, which could perform

the investigation prior to human involvement.

Such a platform would need to be low to the ground for climbing stairs and minor obstacles.

It would need to have a sensor bed for the firefighters to mount the sensors that they would

normally carry in with them, as well as cameras for investigating the site remotely. Lastly, the

platform should have a robotic arm which cannot only open doors and interact with objects, but

could also perform forced entry. Many of the platforms in existence do not have forced entry

capabilities which work on a variety of doors, or the method applied is not suitable for the

volatile environment of a chemical spill or leak. It is because of these reasons that the best

solution for HAZMAT Firefighters is to have a specialized apparatus which meets their needs

and provides additional capabilities and flexibility on scene.

1.3. Literature Survey

The following reading is the literature survey and data gathered which will guide the rest

of the design. The first section will introduce the robot history. The second section will cover the

existing robot models. And the following paragraphs will give detail to various components

involved and several selection options. The final section will entail Hazmat literature history

involving tasks and procedures when facing a hazardous situation. [1]

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Robot history

The first concept of machines being able to accomplish simple tasks where first created in

the early 1800th century using punch cards to send the instructions to an automated loom. Later

in 1899 the first remote-controlled vehicle could make simple forward left and right movements.

The word ROBOT was first used in a movie R.U.R. after the digital computer was built, and the

first computer was created robots where able to do much more complex tasks. In the 1980 there

existed a 6 DOF robot called the UNIMATE. This robot UNIMATE revolutionized the existence

and purpose of robots which brought about industrial robots used in situations which where

dangerous for the human. The robot ASIMO is the most advanced robot today and can achieve

very intricate tasks and has an artificial intelligence capability. Several applications of robots

executing dangerous tasks are robots today that are used by the bomb response unit. This Robot

can disarm explosive chemicals and can provide visual feedback to the unit. Another application

deals with the mining service, when methane gas is present in the work environment and an

accident occurs the environment is combustible and is unsuitable for personnel to repair the

damage. Sending in the robots could assist and prevent future health and safety issues. [1]

When considering a HAZMAT response unit there exists a Robot called the LT2/F

“Bulldog”. The Lt2 severs many similar functions to the senior design project. The Lt2 can open

doors and maneuver inside apartments and as well can use different manipulator attachments to

open the doors. The price for a robot with capabilities such as these cost $20,500 with 4-axis

rotation and a 6 axis rotation which costs $38,500. Another company designed and

manufacturing the LT2 designed a heavy duty Robot the HD2-s .The HD2-s has the capability to

move upstairs while at the same time also able to maneuver upstairs or down stairs. The cost of

the HD2-s is $13,000 for a simple networking package and $21,000 with a advancing more

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robust networking package. Both systems come with a remote video and controller for the user.

[2] Another system already designed is MAARS (Modular Advanced Armed Robotic System)

this system can provide reconnaissance, surveillance, and target acquisition missions which

could safety provide the tasks needed by the personnel. [3] Another design named the BOZ XL

possess Jaws which have 16,500 lbs. of opening force. The Robot as well has the ability to

breach doors and windows. The BOZ XL is primarily used for dismantling and lifting cars and

breaching building doors. [4] Which began in October 1990 called HAZBOT III could identify

and locate the hazardous material incidences. [5]

Robot systems and components

Various rotational actuation systems have advanced throughout the years and every year

these systems are getting smaller, more reliable. For senior design the actuating research will be

focused on compact systems. When considering different rotational actuation systems, there are

Brushless dc motors and brush dc motors. The prices of the step motor depend on which torque

is needed to apply to the system and how much voltage or power is required from the step motor.

The price range is from $5 to over $1000 depending on the design parameters. (Reference)

Another type of rotational actuator is hydraulic this system is very dependable because it is

independent of signals or interference which would cause the robot to move in the correct

distance. There are various battery systems used on the robot designs there are many factors

which will determine which battery to use. For application of hazmat situation the battery would

be best to choose the lithium – Thionyl Chloride battery. This particular type of disposable

battery has been used in computers and electric meters, as well as for providing power to

wireless gas and water sensing equipment. [6] The issue with this battery is that this is

disposable. In the case of non-disposable batteries, would be best to use the lithium-ion batteries.

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The usability of a lithium- ion battery is 3 years. The price of batteries depend on the power

required and the environment as specified earlier. The environments in a hazardous scenario

which may or may not submit the battery to various toxic chemicals and must be completely

insulated from the environment while at the same time be required to output high voltage to the

electrical components. The HAZBOT II system was able to unlock and lock doors as well as use

various cameras to allow for visual inspection of the site and a distance sensor witch relayed the

locations relative to the site. There were a variety of different issues which the HAZBOT need to

be implemented around such as a redesign to operate. The key features of the hazmat project at

JPL include the mobile operator control station which contains two displays and a tether reel to

send and receive the signal. The robot includes a motion system which can traverse forward and

reverse on level surface and inline planes. The system includes a 6 DOF manipulator and uses

non-arching electrical components. HAZBOT III began in October 1990 called HAZBOT III

could identify and locate the hazardous material incidences. [5]

Other applications which robots are being implemented on are bomb disposal and mining

operations, remote sampling and law enforcement. The purpose of implementing robots

throughout the various scenarios is not to replace the member of the workforce but to provide a

tool which to allow for the personal to more efficiently do the task. [5]

Extraction devices are necessary tool for the fire department to use. The examples of application

this is used on is forced entry, damaged window frame of wrecked automobile, automobile

catastrophe scenarios, and scenarios where there is an obstacle and the robot needs to be

implemented. [7]

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There are many types of doorways when interviewing firefighting personal. The first type

of entry is for commercial use uses wood doors with metal handle. The following entry is a metal

door with metal handle. Users also may have the a garage style door which is made of metal and

slides down and slides up to open. This type of metal entry is the most difficult to breach because

there is no handle.

Tread System

Having a tread system allows the vehicle to move through the obstacle with a lower

chance of mud and other debris being carried by the robot. The tread configuration allows for a

combination of both forward and lateral trust capabilities. Another advantage to having a tread

system implemented for the terrain allows for more grip on the stairs and on other alteration

surfaces. The advantages to having a wheel system is that the robot may be able to travel faster

and dissipate less energy do to less contact between the tire and terrain. Due to the less contact

between the tire and terrain do to the reduced contact the robot will have more difficulty with

wheels then tires when moving up the stairs. [8]

Section Hazmat response unit

The following sections will describe the necessity of robotics for hazmat fire rescue. The

event which began the need for hazmat was in 1980 a truck had gone into an accident and spilled

the contents over all the roadway. The material was unknown and could have potentially caused

potential safety hazard. The material was used as a paint additive and food additive and did not

cause hazardous problems. The agencies however saw this as an issue and created a system

called the HAZCAT system. The HAZCAT system was implemented and formed in 1983 to

rapidly identify the unknown substances in the dangerous situations. When the situation arises

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the fire department has to identify the hazardous materials involved in the incident, the

information may or may not be available to the department In which case the department has to

put on a suit which takes up to an hour. The suit is a multi-layer suit. The personnel require full

protective gear including a self-contained breathing. Once the personnel put the necessary outfit

on the personal are allowed to only work 15 to 30 min at a time. Fire department are equipped

with the sensors and detecting equipment necessary to find the chemical substance. [5]

1.4. Survey of Related Standards

Standards serve an important role in our lives all though we may not recognize it.

Standards help organize and unify ideas so they may be used seamlessly from one application to

another. For our purposes these standards will be used to help set goals and guidelines for our

design. Through this project a multitude of disciplines, engineering and other associated

standards will apply. Should a case arise where one standard coincides with another, the more

demanding standard will be adhered to in order to satisfy both sets of guidelines. General

Mechanical engineering standards that will be applied to this design will come from the

American Society of Mechanical Engineers (ASME) and American Society for Testing and

Materials (ASTM). These are generally a necessity for any mechanical engineering work that is

to be designed or constructed.

Our design of a Hazmat Safety Reconnaissance Unit (HSRU or HRU) contains many key

components, each with separate conditions and requirements. By reviewing each of the major

components in depth and looking at the standards and requirements they serve, the limitations

and goals that need to be met can be properly identified. These standards are not limited to the

mechanical design of the apparatus but also include the processes and testing that will be needed

in the full analysis of the project.

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The standards that will be applied to the apparatus will be gone through individually and

their significance in our design will be discussed as a whole, due to the fact that many of these

standards may overlap for several components in the design. The American Society for

Mechanical Engineers is an old engineering society formed in the late 1800’s. This organization

has developed many standards and codes, a majority specifically for the mechanical engineering

discipline. These will be used in the design process for the use of their FOS (factor of safety),

failure, and other deign testing methods. These will allow conservative and reliable figures in our

design, which should be reflected in the actual build [9].

Another important set of standards that will play a factor is ISO, the International

Organization of Standards. ISO is an international organization that promotes worldwide

propriety for commercial and industrial standards. This organization holds several standards in a

variety of fields. For the scope of this project, ISO standards applied to the assessment of tools

and firefighting equipment will be used. Adhering to the ISO standards for tools will ensure a

more globally-minded design, for which it will be easier to source necessary components. [10]

Equally important is the consideration of the hardware to be mounted and used. The

desired form of transportation is through the use of a set of electric motors. The electric motors

follow standards from the department of Energy (DOE). These standards govern the efficiency

level of electric motors as of 1997 and in three categories of electric motors: general purpose,

definite purpose and special purpose. [11] Although the motors that are to be added to the system

are to be purchased from a vendor, the levels of efficiency are critical for electrical design for the

system. These standards will allow for a reliable battery selection process and allow for the

optimal battery to be selected to conserve space and weight.

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One key aspect which should not be overlooked is material selection. The American

Society for Testing and Materials will serve as a main guide for all material aspects of the

design. The ASTM book of standards contains specific information, which covers topics ranging

from material testing to the design of intrinsically safe electrical equipment. [12]

Another major consideration for this project is contact with hazardous materials and

conditions. The safety of the people who will be to operating and servicing this equipment will

be considered and will need to follow guidelines. These standards will come from OSHA, which

stands for the Occupational Safety & Health Administration. OSHA is a part of the United States

Department of Labor they create standards based on safety for workers. Applicable standards

will come from 1926.65 of the code of standards and will serve as a limits and goals in our

design. [13]

Other standards and codes may become more apparent as progress is made. These will

primarily be testing standards as well as others that are not distinguishable given the current

design and goals.

Standards

ASME (American Society of Mechanical Engineers)

ASTM (American Society for Testing and Materials)

OSHA (Occupational Safety & Health Administration)

DOE (Department of Energy)

ISO (International Organization of Standards)

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2. Project Formulation

2.1. Overview

The design is a robotics platform designed to be used in the presence of hazardous

materials. The robot is to be equipped with sensors to perform sweeps of contaminated areas and

relay information to a control center. The HRU will need to be able to traverse common

obstacles found in homes and in commercial buildings such as stairs and locked/unlocked doors.

Finally, the system will need to operate from a control station that can be placed a safe distance

from the contaminated area.

2.2. Project Objectives

The goal is to design a robotic platform for the purposes of HAZMAT scenarios. This

platform is intended to minimize the need for multiple entries into hazardous areas by First

Responders. In order for this system to minimize the amount of entries for the HAZMAT Crew,

it needs to be self-sufficient and self-contained, being able to relay information to the

crewmembers at the perimeter of the scene.

Main Objectives:

1. Robotic system that can operate under hazardous conditions

2. Design and implementation of Modular Clamping System for sensors and equipment

3. Ability to proficiently climb and descend stairs

4. Smoothly perform forced as well as non-forced entry

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2.3. Design Specification

The HRU has been designed to fulfill the purpose of pre-human investigation of HAZMAT

scenes. The main objectives discussed in the previous section represent the cornerstones of

HAZMAT response and therefore the main tasks which the platform must be able to carry out. If

a robotics platform cannot perform all of the tasks, then it has not properly addressed the

challenges of the HAZMAT environment.

The primary goal is for this apparatus to be intrinsically safe. For any electrical device to be

“intrinsically safe” the general requirement is for any possible ignition sources to be sufficiently

insulated or limited so that an explosion or fire will not occur. In the case of this apparatus, there

will be several electrical circuits and all of them will be of considerable amperage due to the

demands that the design will place on the power sources. Additionally, there is the concern of

decontaminating the apparatus. In most cases, a simple hose down or special bath is used to

decontaminate a HAZMAT suit prior to its wearer removing it, therefore, it would be ideal for

this apparatus to be cleansable through similar methods. If all of these needs are to be met, the

only real option is to design every part of the system so that it is completely isolated and

insulated from the environment while staying relatively cool.

The second key objective which must be accomplished by this apparatus is for a clamping

system, which allows already existing sensors to be held and read remotely, to be implemented.

This is a vital part of the design and a key difference between this apparatus and the already

existing robots. HAZMAT teams have a wide variety of sensors and support tools on board their

truck. Additionally, as pointed out by HAZMAT firemen we consulted; the designs of these

sensors and hand-held units continue to change. Because these designs continue to change and

13

the crews are already trained on how to use them, it is more practical to have a modular system

with adjustability, as opposed to a set of sensors which are specific to this apparatus.

Another important feature for this apparatus is a drivetrain which will allow it to climb stairs

with ease. Climbing stairs is no easy feat for robots in general and it will be even more

challenging for this apparatus to do so given the current weight estimate of 500lbs. Like most

robotics platforms that can climb stairs, this apparatus will utilize a tank tread drivetrain. Unlike

most platforms available, it will have a theoretical max output torque of 400ft-lb while only

requiring 153ft-lb to do the job. Apart from climbing stairs it will be very useful to the operators

to have a little extra pushing power available. Equally important is the consideration of the

power required to move the apparatus up a flight of stairs as this will drive the selection of

batteries for the Powertrain. At max torque, each motor draws approximately 162 amperes or 648

amperes for the entire drive circuit. If the apparatus is to operate for 1 hour without stopping, this

is equivalent to 1296 Amp-hours over a 2 hour period.

The fourth and final objective, is for the apparatus to be able to open doors for its self. It is a

simple enough idea that we, as human beings, take for granted. It is not until one has to conceive

a method for opening a door without hands that one realizes the complexity of the task. Most of

all the apparatuses on the market which can open doors, do so by the use of a robotic

manipulator. This end manipulator is usually nothing more than a claw or vice which is deployed

to clench a handle and turn, or press a latch and pull. The end manipulator of this apparatus is the

Jaws of Life, created by Hurst Hydraulics. There are many advantages for using this tool as an

end effector. This tool not only offers the ability to open an unlocked door, but by use of the

spreading heads, a locked door could be pried open by applying leverage to the gap between the

14

door knob and the frame. With a spreading force of 10,000 lbs., there are few doors that will

remain locked as long as a proper purchase point is gained prior to deploying the tool.

2.4. Addressing Global Design

When considering a global market there are multiple design considerations that need to be

made for a seamless implementation of our unit. Considerations such as the physical design, the

materials, and basic controls can be viewed with an international audience in mind. To apple to

the globally ready robot the overall footprint of the robot (length and width) will be limited to the

minimum requirements for door and stairway openings. This will ensure the ability of the robot

completely survey an entire building. The following International building codes will be

implemented and English and International system of units will display both units when creating

design drawings and other procedures:

From the international Building code 2012:

Section 1008.1.1

Section 1009.7

Section R3117.1

These sections describe the international building codes for stairs and doorways.

Using most rigorous design / most rigorous material building code.

Continuing with the physical dimensions of the robot our second global aspect will be to focus

on the material selection of the robot. As with the life of any machine at some point or another

15

some component will need repair and or fail. However, the cost or the availability of the

components will very. Through the use of standard components along with using common

materials such as (aluminum, copper, and certain plastics) the difficulty of repairing/replacing

can be mitigated to the global consumers. As we know availability of certain materials will vary

from location to location, that is why any down time the unit has need to be reduced do to the

important job it performs. As well as incorporating these more available materials the use of

machine able materials will be added when possible. With the need for custom components to be

fabricated, much in the same thought of the availability the use of machine able material

becomes important for down time of the machine.

As stated before SI units will be used for all measurements that apply with the system. SI

units are an internationally accepted set of measurements for many forms of analysis. The use of

this system will ensure a greater compatibility for components. As wellbeing internationally

accepted system will allow for availability for parts and tools globally.

Other global considerations will fall under the controller of the device. It important for

the task the robot is needed to perform be simple and be second nature to the operator. When

conditions are critical experience of the operator is critical. With a more universally accepted

controller the learning curve of the system can be reduced as well allow for a more natural

experience.

Lastly in tandem with a multi-language user manual, a separate maintenance guide will be

created to for common operations the user may need to perform. This guide will contain step by

step instructions for the desired goal. However this guide will contain only pictures illustrating

the required task.

16

2.5. Constraints and Other Considerations

In order to ensure the Hazmat unit could operate in every given scenario the following

sections will describe the required dimensions for building a door and a stair case. The last

section will provide preliminary material requirements for the Hazmat unit.

In Section 1008.1.1 of the International Building code states, “The minimum width of

each door opening must be sufficient for the occupant load thereof and shall provide a clear

width of no less than 32 Inches (813mm). The maximum width of a swing door leaf shall be 48

inches (1219 mm) Nominal.” [14]

For the required dimensions of a stair case there are two codes. One code specifies the

minimum width of the stair and another code specifies the tread of the step. All codes specified

follow the 2012 international building code specifications. For the tread dimension refer to code

1009.7 page 254 of the international building code 2012 which states the minimum stair tread

must be 11 inches. This is the minimum required tread, however depending on the year the stairs

were built the stairs could have a minimum length of 9 inches (228.6). For the step height is also

included could be a minimum of 7.75 inches stair height (196.85 mm). In Section R3117.1 the

overall stair width must not be less than 36 inches (914.4 mm). [14]

The following information was found regarding the Material constraint for the Hazmat

Unit. The section summarizes the outside frame of the unit and the material to which the robot

could be made of and machined. Serval materials and properties are described, at the concluding

section the material chosen for construction was aluminum 6061 this material was chosen due to

cost and the physical properties which are desired over the alternate Materials. The concept is if

this material is chosen is to allow for the fire department like the medical faculty or other

17

companies when the instrument becomes contaminated to ship the material to a decontamination

specialist or 3rd party which could then decontaminate and ship the unit back to the fire

department or medical facility. A majority of medical facility use this practice to sterilize there

equipment and save material costs. [15]

Stainless steel grade 316. This material has a density of 0.29 lbs. /in3. This material is

used in the medical field particularly is used for dentistry and is manufactured into surgical

instruments and other instruments. The average cost for stainless steel is 0.79 $/lbs. companies

such as celitron medical technologies will accept stainless 316 contaminated and sterilize the

material. This material has a low machinability due to the material properties. [15]

Titanium Ti-6Al-7Nb is another constraint which may be used to construct the hazmat

unit. This material is used in the medical industry for implants due to the highly corrosive

resistant material and is 0.16 lb. /in3. The average cost for this material is roughly 20 $/lbs.

companies such as celitron medical technologies will accept titanium and sterilize the material.

This material has a low machinability. [15]

Aluminum 6061 is not used in the medical field without necessary coatings, such as an

anodized coating or powder coat. The density of Aluminum 6061 is 0.0975 lb. /in3. The material

is highly corrosive resistant. The average cost is 0.89 $/lb. companies such as Argonne National

Laboratory specialize in sterilization of material. The material has a high machinability. [15]

Deciding to focus on either anodized aluminum or powder coat aluminum the following

sections outline each coating process.

18

3. Design Alternatives

3.1. Overview of Conceptual Designs Developed

In this next section we will take a closer look at some of the design alternatives which were

considered for the solution to the challenge. The first design featured tank treads in the rear and a

wheeled, rotating assembly in the front, which would allow the robot to climb stairs. After

further research into the topic, it was discovered that the key to stair climbing was engaging the

first step. Once an apparatus has climbed the first step on a flight of stairs, it is just a matter of

maintaining traction.

The discovery of this principle gave inspiration to the second design which features a

completely treaded drivetrain instead of having arms for climbing. The advantage to this

approach is that it eliminates the need for extra motors and programming for the drive system.

However, one disadvantage for the second design concept is that the first link of the arm is fixed

vertically but can be rotated about the vertical axis. This arm design would allow a greater

freedom of movement in the xy-plane but under load, the arm would be susceptible to bending

and could cause instability between the chassis and the ground because of the moment arm.

The third design alternative seems to be the most promising because it addresses the flaws of

the other two systems. The drive is a simple tank tread design with tensioners and guide

sprockets for idlers. Additionally, the arm is pivoted low to the chassis, approximately 18 inches

off of the ground, allowing for stable movement and stability while the arm is in operation.

Furthermore, the front of the drivetrain is twice as tall as the average step, ensuring that the robot

will climb the first step and continue.

19

3.2. Design Alternate 1

For this design the objective is to maintain a relatively small footprint and a lower center of

gravity with the mobility in mind. The general shape is not to change drastically with similar

cues easy to spot. In this design the robot is to be split into two main components, the base and

the arm. The base will serve as the housing for the drive train and the necessary sensors that the

HAZMAT responders use to investigate the seen.

Figure 1: Proposed Drivetrain

The drive train selected will be an electric tank treads system similar to Figure 1 with

triangular set of wheels. The treads will be driven by two electric brushless motors, as well have

a shape similar to the figure that will allow it to climb stairs. This base is also intended to hold

the batteries and other electrical components such as receivers and controllers incased in its shell.

As stated before the design is to be the smallest of our designs with the intention to make it more

agile in smaller areas. The designed footprint is to roughly be 0.6096 m (24in) wide by 0.6096 m

(24 in) long; this size will ensure the robots ability to fit into almost all legal doorways. The top

of the base will also serve to hold the sensors required to fully analyze the scene of hazardous

material. The sensors are not to be designed but to use existing sensors that information can be

20

relayed back to a controller. This will take into account the first two objectives to climb stairs

and to contain an area to place sensors. To address the non-forced and forced entry a 5 DOF

(degree of freedom) robotic arm will be placed on the top of the base. This arm will allow the

controller to perform accurate movement necessary for non-forced entry tactics. At the end of

this arm will be a cutting/spreader combination end effector similar to the Jaws of Life (figure 2).

This end effector will be powered by and electric motor and be geared to produce the appropriate

power needed for forced entry. Cameras will also be mounted at key positions to relay prevalent

information to the driver to control the robot properly.

Figure 2: Jaws of Life

21


Figure 3: Complete assembly

22

Figure 4: Exploded Assembly-

Design overview

The displayed figure 3 and figure 4 are the alternative concept designs developed for the

alternative design 2. This concept is not the final design. This design will focus on the overall

look and shown the general frame including the manipulator. There are 5 components of the

robot will have. When designing the robot, one scenarios where considered such as

decontamination of the overall robot. Another design consideration was the compartment which

A B

C

D

E

23

housed the electrical components must pressurized as to not create a spark and create a sealed

area from environment this housing is shown on part e figure 4. The next part is the lid will

fasten on top of the housing shown on part d of figure 4. The next components are estimated

modelling of the end effector which will be mounted on the lid. Overall dimensions of the robot

are shown in figure 3 are in inches and conversion to millimeters is displayed. The complete

dimensions for the robot are 36 inches length, by 24 inches wide (609.6mm), with an overall

height of 68.54 inches (1740.916 mm). The dimensions are subject to adjustments. All

dimensions where evaluated and are less than the required building dimensions for a door which

are less than the minimum size for residential door.

When considered the objectives described in section 2. The assembly is shown in figure 4

following the dotted lines. The design shown will seal the components from the hazmat

environment which is necessary when considering decontamination. The following objective to

climb stairs is shown in part e of figure 4 which will contain rubber tread around the circular

areas of the sides. The length and width provide the required dimensions to move up and down

stairs. Objective 3 will be mounted to part c of the robot. Simple support through a clamp and

recess will ensure a reliable support for the sensors to be mounted. The manipulator is shown in

part b of figure 4. This manipulator will be powered through electricity and will be used to open

doors through force if required or not.

24


This design features a robust platform that uses tank treads, a four degree of freedom

manipulator, which contains all revolute joints and is fully self-contained. The construction of

the frame will utilize Solid Part and Solid Plate construction. Regardless of the material selected,

choosing to have the overall framework built using these techniques will ensure high durability

and ease of assembly. Although CNC is more expensive than cut and welded frames, there is

more flexibility of design after initial testing if the CNC option is used. Design features, which

can be optimized post initial assembly, include weight balance and reduction as well as the

attachment of accessories in the future. The overall advantages of this platform include the

decreased risk of entanglement, protection for all the internals, and the mobility required for all-

terrain applications and possibly stairs as well. The disadvantages of the design are its overall

size and weight. At just over a meter in length and about 79cm wide, the chassis is very large

when compared with other similar robotics platforms. This size is out of the necessity to house

an array of hydraulic pumps, motors, and batteries onboard the chassis. Additionally, it is

important to note that the overall design differs greatly from other platforms because it sits much

lower to the ground than most. The result is a platform which will be stable and rock less while

moving, which is key for observers and operators at the perimeter of the scene. A steady

platform will provide steady viewing of the environment and stable use of the apparatus. Another

favorable design feature of this platform is that it compartmentalizes every component which

could allow the platform to be made intrinsically safe, much easier than other construction

techniques would allow.

The manipulator will be built like the rest of the chassis, using only solid plates of

material and CNC solid parts. The end-effector of choice is the Jaws of Life, originally designed

25

and manufactured by HURST Hydraulics. These tools are already widely used by fire

departments internationally and are known for their versatility and durability. [16] Normally,

these tools are used for vehicular extrications, as this is typical of a metropolitan area with high

traffic volumes and hence, a higher volume of traffic accidents. The manufacturer, however,

boasts that these tools can be used for forced entry and for pulling heavy loads a short distance.

In fact, firefighters are trained to use these tools for its alternate functions although they usually

have specific equipment designated for certain tasks. [16] The functionality of the Jaws of Life is

certifiable and this tool has seen rigorous testing and many design iterations since its conception

in the 1960’s, making it an ideal tool to be used for the end-effector of this HAZMAT robot.

This design alternative represents a convergence of the advantages of various, existing

robotics platforms, and the attainment of objectives that have not previously been met. It is low

to the ground, fitted with tank treads, and features a hydraulically powered manipulator and end-

effector. All features make it ideal for the purpose it will serve yet, rugged and versatile enough

for HAZMAT teams to use it with confidence.

3.5. Feasibility Assessment

The completion of the project is dependent on several factors. These factors include: Cost

analysis, Manufacturing production, evaluation of objectives, if the project meets all set

objectives.

Furthermore in the area of cost analysis research shows that the fire department does

indeed have the funds $54 million five year capital plan. The projected cost for the unit is to stay

within $20,000 dollars. Giving this projection and the minimum available year funds available to

purchase the hazmat reconnaissance unit. Thus the cost per unit is within the government budget.

[17]

26

In order to implement the manufacturing process funds and correct manufacturing drawings must

be correct and available. The material chosen for the robot is aluminum 6061 T6 not including

the tread. If such actions are completed then the production will be implemented and the

assembly would need to be completed.

Once the manufacturing production and assembly have been completed the following

procedure would be to test and evaluate the robot to further explore if the design follows the

intended objectives. If all the criteria and aforementioned tasks are completed and does not run

into issues, then the feasibility of the assignment will be completely achieved.

3.6. Proposed Design

For the proposed design, the final decision was to create a 35% scale reduction of the original

geometry of the robot, and use a power too weight ratio in order to acquire the same power. As

well our scaled model will weigh approximately 80 lb. and will need to be able to traverse a

range of scaled commercial and residential stairs. To complete this task we have calculated that

we will need motors that can provide 55-60 in-lb. of torque individually. By reducing size of the

robot, the manufacturing costs, as well as electric and mechanical components needed where

readily available. Originally the design would be 40 in by 30 in; the new size is much smaller

14in by 10.5in. The Chassis and platform will be manufactured from aluminum grade 6061,

other accessory mounting hardware will consist of a mixture of 3d printed ABS plastic, on-

corrosive stainless steel hardware and the tread material will consist of acrylic. Communication

will be designed using a combination of Arduino and Vex platforms which pre-exist in the

robotic community. The system will be powered by electricity.

27

3.7. Discussion

There were many factors which affected the final proposed design. Due to cost limitations the

decision was made to rescale the original size. In order to accurately represent the original

model, and use existing tread components which would be compatible with the robot the 35%

was the maximum reduction which would not only present a suitable model, but also facilitate

the mating of components when assembling the robot.

4. Project Management

4.1. Overview

The following Table 1 illustrates the divisions of responsibility for each of the team members.

Table 2 illustrates the timeline for each of the project sections. The timeline is separated by

weeks at the end reaching the 16th week. For the project there are 8 sections: Project

Formulation, Literature Survey, Design / Analysis, Solidworks Model / Cost Analysis,

Prototyping, Construction Testing, Final Design, and Finally Report. Table 3 illustrates the role

and specific responsibilities of each team member. The most difficult aspect of the project was

figuring out how to correctly execute each of the objectives and how to distribute each task.

Once the parameters where calculated the selection process became feasible and the following

sections came together

4.2. Breakdown of Work into Specific Tasks

The following Table 1 illustrates the divisions of responsibility for each of the team

members.

28

Table 1: Breakdown of work into specific tasks

Group

Member

Name

Specific Tasks

Daniel Pico

Evaluate overall project developments, contribution to

component selection, organization presentation, and provided

literature for report sections, collaborated with physical testing.

Oversee entire Project created design for entire project,

Christian

Palomo




Samuel

Caillouette

Evaluate overall project developments such as designing and

presenting an alternative tread option, selection of the battery

and motor, presented alternative methods to reduce the weight

of the chassis, and alternate manufacturing options.

Timeline for work and progress

The following Table 3 illustrates the timeline for work and progress.

29

Table 2: Timeline of Project

4.3. Breakdown of Responsibilities Among Team Members

The following Table 2 illustrates the divisions of responsibility for each of the team

members.

January February March April May June July August September October November December

Project Formulation

Liturature Survay

Research

Design and Analysis

Solidworks Model

Cost Analysis

Prototyping

Constuction

Testing

Final Design

Report

30

Table 3: Breakdown of Responsibilities among Team Members

Group

Member

Name

Role

Description

Daniel Pico

Team Leader /

Project

Designer

Oversee entire Project, create design

Christian

Palomo

Project Analyst




Samuel

Caillouette

Project Analyst




31

4.4. Patent/ Copyright Application

The following HAZMAT ROBOT senior design project purpose is solely designed and used

for academic purposes, all components and manufacturing components will be acknowledged.

There will be no pursuit of commercialization or Copyright application for the HAZMAT

ROBOT.

4.5. Commercialization of the Final Product

There will be no pursuit of commercialization or copyright application for the HAZMAT

ROBOT.

4.6. Discussion

Then most difficult aspect of division of responsibilities was first assessing the areas of the

project that needed attention. For most of the Project the decisions where discussed and agreed

upon, for example: a purchase or design consideration. Using the budget and the chassis

dimensions as a constraint, many design considerations and component selection where selected

using those parameters as a reference.

5. Engineering Design and Analysis

5.1. Overview

The following sections will illustrate the Component analysis and Component selection of

the HAZMAT Robot. The primary systems which are being analyzed are the: power system,

tread system and the structure of the robot. Many Component selections are based off of the

clearance constraints from the original design. Using the building codes as a guide the other

dimensions for the design could be extrapolated and once the chassis was designed both

32

mechanical and electrical components may be selected. Lastly the cost evaluation will be

discussed.

5.2. Kinematic Analysis

Table 4: Nomenclature for Kinematic Diagram and Equations for Static and Dynamic Analysis

Symbol Description SI Units

θ Angle of incline ∘(degree) or radians

Fix

Net force in the horizontal

direction

Lb.(pounds)

Fy

Net force in the vertical

direction

Lb. (pounds)

M Net moment Lbf-in (pound - in)

r Radius of wheel inches

w Weight of robot W= mass x gravity = Lb.

Wb Weight of robot belt Wb= mass x gravity = Lb.

N

Net Normal force acting on

the robot

Lb. (pounds)

33

Figure 5: Drive is stopped, free body diagram of robot static situation

∑ 𝐹𝑥 = 𝑓 − 𝑤 sin 𝜃 (Equation 1 (force in the x-direction) Static Situation)

∑ 𝐹𝑦 = 𝑁 − 𝑤 cos 𝜃 (Equation 2 (force in the y-direction) Static Situation)

∑ 𝑀 = 0 (Equation 3 (Net moment) Static Situation)

∑ 𝑇 = 𝐹𝑟 × 𝑟 (Equation 4 (Net Torque) Static Situation)

Figure 6: Net weight of 1/3 scale robot and corresponding static torque

Loads Location From Center Angle Radians Resistance Norm Resultant Force

Torque applied to Drive

due to gravity(in-lbf)

Available

Torque Residual

Chassis 30 0 0 0 0 12.000 60.000 12.000 21.00 2428 2449

Batteries(Drive) 20 0 0 10 0.174533 11.818 59.088 1.399 2.45 2428 2430.448

Batteries(Hydraulics) 10 10 0 20 0.349066 11.276 56.382 -9.245 -16.18 2428 2411.821

Arm 0 25 10 30 0.523599 10.392 51.962 -19.608 -34.31 2428 2393.687

Motors 0 -10 0 40 0.698132 9.193 45.963 -29.375 -51.41 2428 2376.594

Pumps 0 -15 0 50 0.872665 7.713 38.567 -38.249 -66.94 2428 2361.064

Total Projected Weight 60 60 1.047198 6.000 30.000 -45.962 -80.43 2428 2347.567

34

Figure 7: Dynamic model, drive is in motion climbing

∑ 𝐹𝑥 = 𝑚𝑎𝑥 = 𝑤 sin 𝜃 − 𝑓 + 𝑤𝑏 sin 𝜃 = −𝑤𝑏

𝑔𝑎𝑏

(Equation 5 (force in the x-direction) dynamic Situation)

∑ 𝐹𝑦 = 0

(Equation 6 (force in the y-direction) dynamic Situation)

Using principles of trigonometry one could extrapolate the force necessary to overcome the

friction and weight of the robot. By estimating the force the next step would be to be to calculate

the torque. Using a diameter of 2.111 inches we could find the estimate the necessary variables

shown in table 4.

35

5.3. Stress Analysis

For this analysis the tread chain will be analysis under a tension load. Since the force of

the tread chain will be distributed across each tread link in order to achieve an idea of the shear

across the pin and link. Another stress analysis dealt with the thickness of the side panels under

load, with pockets and without pockets there was a significant difference in the behavior of the

part under stress as shown in section 5.10.

5.4. Mechanical Analysis

Gear analysis of system

The gear analysis is first conducted using eq. shown below which takes into account the

diameters of the driving gear to the driven gear to establish a gear ratio which can then be used to

find the rpm of each gear. Since gear 1 and 2 are the same diameter, there is a 1:1 gear ratio.

Gears 3, 4, and 6 are also the same diameter which means that they have the same gear ratio. A

representation of the gear system is shown below in figure 8. The Rpm of the motor is 38 rpm

(revolution per min), this will be the initial speed of the first gear.

Figure 8: Gear System

36

𝑛𝐿 =𝑁𝐹

𝑁𝐿× (𝑛𝐹) (𝐸𝑞. 7 𝐺𝑒𝑛𝑒𝑟𝑎𝑙 𝐸𝑞𝑢𝑎𝑡𝑖𝑜𝑛)

𝑛1 = 𝑛2 = 2.110

2.110× (38) = 38 𝑅𝑃𝑀 (𝑔𝑒𝑎𝑟 𝑟𝑎𝑡𝑖𝑜 𝑓𝑟𝑜𝑚 𝑔𝑒𝑎𝑟 1 𝑡𝑜 𝑔𝑒𝑎𝑟 2)

𝑛3 =𝑁2

𝑁3× (𝑛2) =

2.110

1.130× (38) = 70.96 𝑅𝑃𝑀 (𝑔𝑒𝑎𝑟 𝑟𝑎𝑡𝑖𝑜 𝑓𝑟𝑜𝑚 𝑔𝑒𝑎𝑟 2 𝑡𝑜 𝑔𝑒𝑎𝑟 1)

𝑛3 = 𝑛4 = 1.130

1.130× (70.96) = 70.96 𝑅𝑃𝑀 (𝑔𝑒𝑎𝑟 𝑟𝑎𝑡𝑖𝑜 𝑓𝑟𝑜𝑚 𝑔𝑒𝑎𝑟 3 𝑡𝑜 𝑔𝑒𝑎𝑟 4)

𝑛5 =𝑁4

𝑁5× (𝑛4) =

1.130

4.99× (70.96) = 16.09 𝑅𝑃𝑀(𝑔𝑒𝑎𝑟 𝑟𝑎𝑡𝑖𝑜 𝑓𝑟𝑜𝑚 𝑔𝑒𝑎𝑟 4 𝑡𝑜 𝑔𝑒𝑎𝑟 5)

𝑛6 =𝑁5

𝑁6× (𝑛5) =

4.99

1.130× (16.09) = 70.96 𝑅𝑃𝑀 (𝑔𝑒𝑎𝑟 𝑟𝑎𝑡𝑖𝑜 𝑓𝑟𝑜𝑚 𝑔𝑒𝑎𝑟 5 𝑡𝑜 𝑔𝑒𝑎𝑟 6)

Bearing Analysis

The bearing analysis consists of each of the shafts which will rotate freely. In order to

correctly determine if the Bearing will operate under the required conditions, for each shaft

requiring a bearing the catalog rating was calculated using an overestimation of force parameters

and standard Weibull parameters for ball bearings the result showed a high catalog rating. Using

the Catalog rating, the bearings chosen for the application will need to have either an equal or

greater load rating compared to the Catalog rating. Below figure 9. Catalog rating for the

bearing. For a simple analysis the thrust force is taken to be negligible. The example shown

below was repeated for the other shafts following. The Weibull parameters are shown on table 5.

For the catalog rating of 763 lb. the bearing is shown the dynamic capacity for a double shielded

bearing will provide a dynamic load of 1,200 at $12.02. [18]

37

Figure 9: Bearing Free Body Diagram

Figure 10: Related nomenclature and application conversion factor

38

Table 5: Weibull Parameters

Weibull parameters

X0 0.02

b 1.483

a 3

(theta-x0) 4.439

Application factor 2

𝑥𝑑 =𝐿𝑑

𝐿10 (𝐸𝑞. 2 𝐺𝑒𝑛𝑒𝑟𝑎𝑙 𝐸𝑞𝑢𝑎𝑡𝑖𝑜𝑛 𝑓𝑜𝑟 𝑑𝑖𝑚𝑒𝑛𝑠𝑖𝑜𝑛𝑙𝑒𝑠𝑠 𝑑𝑒𝑠𝑖𝑔𝑛 𝑙𝑖𝑓𝑒)

𝐿𝑑 = 60 × (10000) × 𝑛𝐷 (𝐸𝑞. 3 𝐺𝑒𝑛𝑒𝑟𝑎𝑙 𝐸𝑞𝑢𝑎𝑡𝑖𝑜𝑛 𝑓𝑜𝑟 𝑑𝑖𝑠𝑖𝑟𝑒𝑑 𝑑𝑒𝑠𝑖𝑔𝑛 𝑙𝑖𝑓𝑒)

𝐿10 = 10 6 𝑟𝑒𝑣𝑜𝑙𝑢𝑡𝑖𝑜𝑛𝑠 (𝐸𝑞. 4 𝑟𝑎𝑡𝑖𝑛𝑔 𝑙𝑖𝑓𝑒)

𝐶10 = 𝑎𝑓𝐹𝑑 [𝑋𝐷

𝑥0 + (𝜃 − 𝑥0)(1 − 𝑅𝑑)1

𝑏⁄]

1𝑎⁄

(𝐸𝑞. 5 𝐺𝑒𝑛𝑒𝑟𝑎𝑙 𝐸𝑞𝑢𝑎𝑡𝑖𝑜𝑛 𝑓𝑜𝑟 𝑐𝑎𝑡𝑎𝑙𝑜𝑔 𝑙𝑜𝑎𝑑)

Example:

𝐹𝑟 = √502 + 502 = 70.71 𝑙𝑏𝑓 (𝐸𝑞. 6 𝐺𝑒𝑛𝑒𝑟𝑎𝑙 𝐸𝑞𝑢𝑎𝑡𝑖𝑜𝑛 𝑓𝑜𝑟 𝐸𝑞𝑢𝑖𝑣𝑎𝑙𝑒𝑛𝑡 𝑙𝑜𝑎𝑑)

39

𝑥𝑑 =60(10000)(38)

106 = 22.8 (𝐸𝑞. 7 𝐺𝑒𝑛𝑒𝑟𝑎𝑙 𝐸𝑞𝑢𝑎𝑡𝑖𝑜𝑛 𝑓𝑜𝑟 𝐸𝑞𝑢𝑖𝑣𝑎𝑙𝑒𝑛𝑡 𝑙𝑜𝑎𝑑)

𝐶10 = 2(70.71) [22.8

0.02+(4.439)(1−0.99)1

1.483⁄]

13⁄

= 765.56 lbs. (eq.8 catalog rating)

5.5. Material Selections

There are several materials that where considered for the construction and fabrication of the

robot. Material being used on the robot will consist of metal alloys and plastics along with fluids

used for lubrication. Chemical batteries will be discussed in the power section 5.7.When

considering the materials being used for Hazmat reconnaissance there are several factors which

must be considered. The factors that must be considered for material selection are: machinability,

strength, cost, and feasibility of being decontaminated. The following table 6 illustrates the

various materials and the corresponding factors used for construction of the platform.

40

Table 6: Material Selection Properties for common metal grades

Each of the columns represent a property of the material. The first column is Machinability.

In order to calculate machinability there are many aspects and conclusions that must be taking

into account some of the aspects may be surface finish Brinell hardness, and how much power

would be required to cut into the metal for example in the case of the experiment a material was

turned on the lathe and then cut into. [19]The following column illustrates the Brinell hardness

number for each of the materials. For the purposes of the application we decided to use the

highlighted materials, Aluminum, Stainless, and Plain Machine able. The next column displays

the cost per pound of the metal. Depending on the supplier the cost could vary depending on how

much material to purchase. The smaller the quantity the more expensive and with the higher

quantity the lower cost. An average cost was tabulated to in order to achieve a more practical and

true value for the materials. [20] The final column shows the level of decontamination. The

Metal

Machinability

(power

required for

turning hp.

Per cu in per

min)

Hardness

(Brinell)

cost per

lb

feasibility of bieng

decontaminated

Aluminum 5005

0.1-0.2 28 0.66 low

Aluminum 60610.1-0.2 65 0.66 low

Stainless 316

0.5-1 149 0.79 high

plain

machinable

steel 1045 or

0.5-1 163 0.09 low

Titanium 6AL-

4V Eli Titanium n/a 379 1.97 high

pharmaceutical processing equipment, marine

exterior trim, surgical implants, and industrial

equipment that handles the corrosive process

chemicals used to produce inks, rayons,

photographic chemicals, paper, textiles, bleaches,

and rubber.

used for axels, bolts, forged connecting rods,

crankshafts, torsion bars, light gears, guide rods

biomaterials, biomedical implants,

biocompatibility

Applications

Factors considered

Material Selection Properties for common metal grades

Cooking utensils, decorative trim, awnings, siding,

storage tanks, chemical equipment

truck bodies and structural components

41

standard in order to classify the feasibility of decontamination of a metal uses DF or

(Decontamination Factor). The Decontamination factor measures the effectiveness of a

decontamination process. Mathematically the DF is a ratio of the change in state of the

radioactivity of the material. The final column of the material properties table illustrates the

various applications used for each of the metals. [15] The Primary metal alloy that will be used

in the construction of the robot will be aluminum 6061, Stainless 316 and plain Machine able

steel. These alloys where chosen do to the cost per pound and the function needed for the

application. Ideally if cost was not an issue and the method of manufacture was not an issue

Titanium would be the choice for construction of the robot do to the high strength and the

decontamination level. This alloy will be used due to the corrosive resistant properties, and the

density of aluminum is much less than other alternative metals. Another reason is that the cost of

Aluminum is much lower than other metals. Aluminum 6061 is primary used to construct the

chassis of the Robot, other alloys are metals used in ball bearings and steel alloys are used for the

bolts.

The primary Plastics will be PLA or (Polylactic Acid). PLA is used because it is a bio-

degradable type of plastic. PLA will be used to construct the shelf used to house the sensors and

other fastening supports. [15]

42

5.6. Finite Element Analysis

Figure 11: Simulation of tread track using POM Acetyl Copolymer

Figure 12: Stainless Steel Chain link

The following figures 11 and 12 illustrate the alternative solutions to implement the tread

system. Figure 12 has an Ultimate tensile strength (UTS) of 90 ksi (kilo pounds per square inch)

which the simulation proved the load is below the UTS by a factor of 10. Figure 11 displays a

maximum stress of 29 ksi (kilo pounds per square inch), which would be under the yield stress

43

for POM Acetyl Copolymer of 17 KSI providing a factor less than 1. Using this tool as an

estimation, the decision was made to use the stainless steel links.

Figure 13: Panel without Pocket

Figure 14: example of panel with pocket

The following figures above illustrate a side panel. For this problem the goal was to

investigate which panel would yield a higher stress. By reducing weight shown in figure 14 using

44

the same material, one may observe figure 13 to show a lower stress. By examining the points

the conclusion was to consider the minimal use of pockets when necessary.

5.7. Motor analysis and selection:

The following discussion is going to discuss the different aspects of the motor selection. The

factors which contribute to the selection of the motor involve: Power Requirement, Weight of

robot, current draw, Torque required, and duty profile. When considering the factors the initial

decision was to use the full scale robot however do to budgeting complications the design of the

robot was too use the same system and scale down the weight to the 35% scale reduction. With

the reduction incorporated the following table 7 illustrates the total projected weight and required

torque for the system.

Table 7: Projected Weight Analysis and Torque by considering varying degrees of incline

Loads weight (lb) Angle of incline Radians

Resistance

(lb)

Resultant Force

(lb)

Torque applied to

Drive due to

gravity(in-lbf)

Chassis 150 0 0 16 16 17.84

Batteries(Drive) 110 10 0.17 15.76 1.87 2.08

Batteries(Hydraulics) 0 20 0.35 15.04 -12.33 -13.74

Arm 80 30 0.52 13.86 -26.14 -29.15

Motors 60 40 0.7 12.26 -39.17 -43.67

Pumps 0 50 0.87 10.28 -51 -56.86

Total Projected Weight 80 60 1.05 8 -61.28 -68.33

70 1.22 5.47 -69.7 -77.72

Assumed coefficient of friction *0.2 is half of 0.4, the suggested coefficent of STATIC friction for rubber against slick surfaces

45

Table 8: Power Requirement when submitted to a 70 degree incline

Table 8 illustrates the duty profile weight projection and the maximum current draw for

each motor. These approximations take into account a power to weight ratio of 1.6, which can

also be taken as the safety factor. The original projected weight for the full scale robot is 400lbs.

with the power to weight ratio the adjusted weight taking 400 and dividing by the 1.6 should be

80 lbs. again this value is an overestimation of the power requirements and torque requirements

assuming the robot will continuously climb a 70 degree incline. Note the Duty profile classified

for the system will undergo periodic drive and stop motions with electric braking. The first motor

considered for the system is shown in figure 15 shows the MMP-TM57 Geared Motor. Figure 16

illustrates a similar almost exact motor however the difference between the TM57 and the TM55

is that the Torque output is less. The following table 9 illustrates the specifications for each of

the motors considered for selection of the Hazmat robot.

Less then Power

Requirement =

VI (watts)

WIEGHT INCLINE voltage (V)current

(amperes)Torque (in-lbs)

720 80 LBS 70 DEG 12 less then 60 60

Torque (in-lbs) Torque (oz-in) Torque (Nm)

60 960 6.78

Duty Profile

S7 - Continuous

operation periodic duty with electric

braking

35% Scaled down model-Current Robot

46

Figure 15: MMP-TM57 Geared Motor [21]

Figure 16: MMP-TM55 Geared Motor

47

Figure 17: Amp flow E30-400 Motor [22]

Table 9: Motors considered for selection

5.8. Battery Selection

For the battery selection, we will be basing the size on two important factors. These

factors are runtime as well as weight. The runtime is the amount of time that the robot will be

able to operate before the batteries are depleted and the robot can no longer perform its

functions. For this we are have defined based on information that a runtime of 30 min will be

adequate for the robots tasks. Due to price reasons the batteries that will be used will only be led

acid batteries therefore not much can be done in consideration for the weight. In the future other

battery technology can be considered to improve on this aspect, such as Lithium Iron Phosphate

(LiOP4) that has a higher energy density.

model Gear Reduction Rpm at load rated Continous Torque (in-lbs) rated peak Torque (in-lbs)

MMP-TM57-100 100 44 109 443

AmpFlow E30-

400 Motor n/a 5700 n/a 93.75

MMP-TM55-100 99:50:01 44 100 348

48

For led acid batteries we can uses equations based one Peukert’s law and be able to

determine the capacity needed to run the robot for our 30 min time period. These batteries will

only be powering the drivetrain of the robot, which is made up of two Midwest Motion motors.

These two motors as seen in the figure will produce a max draw of 7.2 Amps each totaling 14.4

Amps. This is what we will use to determine the worst-case scenario to power the motors at max

load.

Figure 18: Drive Motor Current Draw

With a continuous draw of 14.4 Amps we can gage the capacity required for the batteries. Due to

the fact that we are using sealed led acid batteries we can use Peukerts’s equations.

𝑇 = 𝐻 (𝐶

𝐼𝐻)

𝐾

T= Time (hr)

H= Amp Hour rating (AH)

C= Amp Hour capacity (AH)

I= Load Applied (Amp)

K= Peukert’s Exponent

Solving for the capacity:

𝐶 = 𝐼𝐻 ∗ (𝑇

𝐻)

1𝐾

49

However, Peukert’s exponent is still needed for this calculation. Peukert’s exponent

depends on the type of battery used for our purpose we are using an Absorbent Glass Mat

(AGM) led acid battery which has a K value between 1.05 to 1.15 (closer to 1 is better). Using a

conservative value of 1.15 we have a theoretical capacity of 11.65 Amp Hours (AH). This is not

however this would imply depleting the batteries completely, which degrades the battery. It is

normally recommended to maintain a 50% charge to keep batteries healthy. Ultimately a battery

with 24 AH capacity will be ideal for hour needs, however dude to our size constraints for testing

16 AH (combination of 2 8 AH batteries) will be used. This still gives a estimated run time of

21.6 minutes which is adequate for testing.

50

The batteries that were chosen for the prototype testing were Power Sonic PSH-1280 8

AH batteries. The reason these batteries were chosen was due to its many good qualities. From

research these batteries had the best capacity to weight ratio about 1.33 lb. per AH. As well this

kind of sealed led acid battery boast being flame retardant as being AGM.

As eluded by the calculations the battery configuration that was chosen was to run two of

these in parallel configuration. Being in a parallel configuration the motors will have access to

twice the amount of amps. Whereas a series configuration would allow only the amount of amps

equals to one battery with double the voltage, which is outside of the recommended range of the

motors the illustration in figure 18 explains these properties. This is something that is usually

done in order to meet the current demands of the mothers under load. However with the selection

of the PSH-1280F2 each individual battery can supply a constant of a 20 amps and a max of 25.5

amps for a duration of 7 min, illustrated through figure 21. This decision was made to both allow

for maximum allowance of amps to be supplied to the motors and other accessories as well to

simplify the circuit and allow for a single “kill” switch in an emergency situation.

Figure 19: Parallel vs. Series configurations [23]

51

Figure 20: Power Sonic PSH-1280f2 [24]

52

Figure 21: Performance Specifications for PSH-1280F2 Battery [25]

53

5.9. Communication system

With all robotic platforms there is a need for a translator to transfer the input commands

from the user to the robot machine code. The complexity of this device follows the inputs and

outputs that are required for its tasks. For the prototype design many different communication

systems were considered with for this design all with their own positive and negatives.

Arduino

The Arduino is very common micro controller; it finds itself used in many small DIY (do

it yourself) projects. This is the first controller that was considered. It has many advantages being

relatively inexpensive due to the fact that it is an open platform with many different

manufactures. As well-being open platform this board also has many different accessories and

support for a large community.

Figure 22: Arduino Mega [26]

54

However the one major downside with this platform for when considering the full scale

design was with the consideration of having multiple video streams that would be processed and

sent from the Arduino board. Although being very adaptable the Arduino platform is not a very

powerful one. With this system it was not recommended to used due to lack of processing power

from multiple online forums. The other option that was universally recommended was the

raspberry pi microcontroller.

Raspberry Pi

The Raspberry Pi is a microcontroller much like the Arduino in its basic operations and is

open source. One of the main differences that distinguish the Raspberry Pi from the Arduino is

its processor it use s and ARM processor. This Processor is much more powerfull and can there

for process more instructions. The diffrence is much more noticebale with he second itteration of

the Raspberry Pi 2 which stouts a quad core processor allowing to handle more streams which

would be needed handle multiple videos streams along with basic motor instructions to a motor

controller. This however does have some cons, the type of programing required for this system is

much more difficult when compared to the Arduino and has a much steeper learning curve even

with other programing experience and many helpful communities. With all considerations the

Raspberry Pi 2 would be the optimal choice for the full-scale design.

55

Figure 23: Raspberry Pi [27]

However with the need to downscale the design and only focusing on prototyping the

design a microcontroller with the capabilities of the Raspberry Pi 2 and Arduino were neither

necessary nor available within the budget. Exploring other options the choice became clear when

considering the Vex Platform of which we have experience with using and coding with.

Vex

Vex is an organization that holds robotic completions for both high school and college

level participants. Similar to the Lego Mindstorms vex tries to appeal to young students and

encourages them to design and build robots for the use in their competitions. The consideration

with using this platform starts with the ease of use as stated prior experience will medicate any

learning curve as well the vex components fit within the needs of the design. This system also

natively is ready to work with a physical controller natively. This is greatly simplifies the process

when compared to the pervious platforms where a controller would need to be sourced and coded

56

into the microcenter. The one major drawback to the vex system is video recording is not

supported with the microcontroller meaning video really would need to be transferred by another

system. Lastly we were able to borrow a unit like the system seen in the figure below for testing

purposes.

Figure 24: Vex microcontroller brain, Controller, Receiver [28]

Coding the Vex brain is a very simple process do to the fact that the system is used to

teach younger students how to program. The basis of the coding is C++ in a program rightfully

called EazyC. The Code listed below shows the simple code used in order to control the motors

through the use of the motor controllers.

57

Figure 25: Code applied for tank drive onto robot

5.10. Speed Controllers

The speed controllers also known as a motor controller is a device that allows for the

control of the amount of amps to be supplied to a given electric motor. Essentially the motor

controller can be seen as a valve controlling the amount of current and therefor the power of the

motor. These devices are needed in most robotic application where the microcontroller cannot

supply the motor with the required voltage or amps. Similarly with our use case the vex

microcontroller cannot supply the necessary voltage or current the motors supplied for this

design (12 Volts 7.2 AMP). For our case the speed controller selected would need to fall in the

58

dimensions of the specifications of the motors. It is important in the selection process that the

speed controllers do not just meet the requirements of the motor they are known to overheat

when reaching their limitations. Other considerations into the size of the speed controller and the

method of communication to the microcontroller are taken into count for proper fitment into the

overall system. For these reasons the decisions was to go with the Victor SP motor controller, a

Vex motor controller that can more than handle the needed throughput of the MMP motors.

Figure 26: Comparison of Vex Motor Controllers [29]

59

From the figure above it can be seen the Victor SP motor controller has a nominal voltage of 12

volts and a rated continuous current of 60 Amps well above the condition that are planed to be

run. As well this speed controller when compared to others has a relative small form factor

which works well with the scaled down prototype.

Figure 27: Victor SP Interface Dimensions [28]

60

5.11. Camera

As previously noted the camera that is to be mounted on the prototype will not be directly

linked to the microcontroller operating the robot. This was do to the lack of video support on the

vex platform. However video relay does not need transmitted from the microcontroller. The

other option is to a self-contained system, one that can transmit the video wirelessly on its own.

As well due to the constraints to build a prototype rather than full scale the camera selected

would not need to stand to conditions that would be expecting in a full size unit. This testing

exception allowed for a more relaxed selection in the specifications for the camera. This is where

a single ip camera is used in order to test basic surveillance and field of view testing.

Figure 28: D-Link 931L ip Camera [30]

Shown in the figure above the ip(internet protocal) camera selected is a D-Link 931L ip

camera. This product was chosen due to its small size and wireless capabilities. Being an ip

camera it only requires a router to connect to and as long as there is a connection to the router the

video feed can be remotely accessed by anyone able to connect to the network. However as

61

illustrated in the diagram above the camera does require a direct feed of current in the form of a

DC connection.

In order to maintain the supply needed for the camera and to continue to have the system

untethered. A system had to be devised to convert the power going out of the batteries (12 Volt)

to a usable voltage for the camera, which requires 5 Volts at 1 Amp. The use of a voltage

regulator was connected into the circuit in order to perform this task. A voltage regulator is a

device with converts the input voltage from high voltage to low. There are many different kinds

of regulator that work for different inputs and output voltages. For the needs of this system the

use of a L7805, which works for 12v to 5v. It is also very important to use a heat sink with these

devices depending on the use. The heat skink is needed in order to expel the power loss through

the regulating process.

𝑃 = (𝑉𝑖 − 𝑉𝑜) × 𝐼

𝑖. 𝑒. (12 𝑉𝑜𝑙𝑡𝑠 − 5 𝑉𝑜𝑙𝑡) × 1 𝐴𝑚𝑝 = 7 𝑊𝑎𝑡𝑡𝑠

For the case of this design the heat sink would require to dissipate 7 watts of heat from

the device.

62

Figure 29: Example Circuit Diagram for Voltage Regulator [31]

The figure above shows an example circuit diagram for the voltage regulator. As well, not

specified in the diagram there are two capacitors connecting the positive leads to the ground

connection. This is done to mitigate the noise that is created by the voltage altering process.

5.12. Electrical Circuit

The electrical circuit servers as an important part in any robotic design. Due to the

relatively small nature of the prototype being constructed, the design of its circuit follows a

similar trend. The circuit of this robot contains only a few components as listed in the table

below.

63

Table 10: Items in circuit

# Item Quantity

1 12 volt battery 2

2 7.2 Volt Battery 1

3 Switch 1

4 Power Distribution 1

5 Voltage Regulator 1

6 10 μF Capacitor 2

7 2 Amp Fuse 1

8 10 Amp Fuse 2

9 Camera 1

10 Speed Controller 2

11 12 Volt Motor 2

12 Vex Microcontroller 1

These items bring together both the circuit for the Vex micro controller as well as the

circuit for the motors, which are serrated in terms of power source. This can be seen clearer in

figure 30 which shows the layout of the entire circuit. In the illustration of this circuit it can be

64

seen the source of energy for the motors comes from a pair of 12 Volt Led Acid batteries that are

configured in parallel. Immediately introduced is the use of a “kill” switch where the robot can

be disconnected from the power source in an emergency situation. This power is then distributed

out to the two speed controllers and camera through the use of a distribution board. Here other

safety measures are taken with fuses leading out for each component in the case where it could

be over loaded. As shown the circuit for the microcontroller is on a separate circuit with its own

power supply. This is due to the proprietary nature of the Vex components that a separate batter

was used for it. Ideally the entire system would be run purely off the two 12 Volt led acid

batteries in parallel with its appropriate fuse feeding off the power distribution board. The

advantage of this would require less space for the batteries. Also unifying the circuit would allow

the microcontroller to be safer position with a fuse for over loading and immediate shutdown

with the use of the “kill” switch.

Figure 30: Circuit Diagram of Prototype Robot

65

5.13. Proposed Drive Train Cost Summery

The following table 11, will illustrate the purchases and the part cost break down. The initial

section will include the readily available parts which were able to be purchased either online or

at a local vendor. The corresponding section projects the manufactured parts and costs associated

with each section such as the chassis, mounting parts, and assembly hardware.

Table 11: Cost Breakdown

Robotics Cost Sheet

# Description Quantit

y Total Price

Date of Purchase

Location of Purchase

1 Drive Motors 2 $522.00 9/21/15 Midwest Motion

Products

2 Batteries 4 $71.69 9/22/15 AtBatt.com

3 Battery Charger 2 $20.26 9/22/15 Amazon.com

4 Camera 1 $40.00 9/22/15 Tiger Direct

5 Bearing 36 $89.90 10/9/15 Blair Bearings

6 Sprockets 18 $113.70 10/9/15 BBManufactureing

7 Water Jet 1/2 4 $156.00 10/9/15 Nautic Waterjet Fabrications,Inc

8 Water Jet 1/2 4 $150.00 10/9/15 Nautic Waterjet Fabrications,Inc

9 Reamers 4 $194.79 10/21/15 Shars Tooling Company

10

Raw material Several $66.59 10/22/15 Simons Stainless Surplus

11

Victor SP 2 $127.18 10/26/15 Robot Market Place

12

Dewitt tools Several $43.00 10/26/15

Dewitt tools

13

Dewitt tools Several $43.00 10/26/15

Dewitt tools

14

McMaster tools Several $335.00 11/1/15

McMaster Tools

15

Dewitt tools 2

$9.00 11/2/15

Dewitt tools

1 Electronics Several $11.00 11/2/15 Alpha Electronics

66

6

17

Sprockets 16

$193.00 11/2/15

Blair Bearings

18

Suspension Several $16.00 11/7/15 CEWater Jet

19

Panels/ Motor Receivers 4

$250.00 11/23/15

Zicarelli

20

Electronics 2

$45.99 10/27/15

B&F Marina

21

Tools 7

$30.00 11/7/15

Tools and equipmetnt sales corp

22

Bushings 6

$40.00 11/8/15

Ace

Complete Estimated cost: $2,568.10

6. Prototype Construction

6.1. Overview

The following sections will illustrate the prototype model. The prototype model will

consist of description, design section, construction section, parts list, and cost analysis. The idea

of the prototype is to facilitate the same objectives as a full scale representation of the robot

through all the same challenges as a smaller scale. Before reconstruction of the full scale model

the prototype will require a lower cost to construct and will facilitate all testing requirements

before being applicable to full scale.

6.2. Description of Prototype

The HAZMAT ROBOT prototype will be a one-third scale representation of the actual

scale robot. The geometry will be scaled down one third of the original size and the power to

67

weight ratio will maintain the same. In order for machinability purposes and cost limitations the

material of the robot prototype will be aluminum 6061, however as stated earlier the optimal

material would be a grade of titanium or easily decontaminate materials used for the medical

application. The motors will deliver 100 in-lbs. of continuous torque the batteries will be 12v 7.2

amperes. For the prototype a flight of stairs will be constructed and will follow the residential

building code regulations. The tread system will use number 35 chain as the belt and the number

25 chain as the driving chain.

6.3. Prototype Design

The following figure illustrates the prototype of the robot. The overall chassis of the

robot consists of 4 panels: 2 outer panels, and 2 inner panels. The space in the center of the robot

houses the battery compartment and the motors. The motors are mounted parallel side by side

from each other. The outer space on each side will contain the sprockets and drive train of the

system. Each side will have an independent motor allowing for reverse, full range of planer

motion. The tread system will comprise of a belt covering the chain links which will sit on the

sprockets. By designing the robot with a high torque and low center of gravity the robot will be

able to quickly traverse up and down inclines.

68

Figure 31: Prototype Model of the HAZMAT ROBOT

When designing the prototype many factors needed to be considered and implemented in the

modeling stage before beginning the manufacture the parts. The budget for the build was first

determined then after the budget was calculated design components for the robot could be made.

Ultimately much of the support structure was machined using a 3-axis CNC (computer numerical

control) milling machine or using a drill press. With collaboration the panels were able to be

water jetted. Another difficulty was the tread system. The decision was made to create a tread

system using existing links and a universal pulley belt, which would be able to purchase at any

online hardware store. The build is currently in progress however the expected completion of the

assembly will be November 6, 2015.

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6.4. Parts List

The following table will illustrate all components being assembled on the hazmat robot.

There will be parts which are being manufactured and already manufactured parts which are

reflected on the table.

Table 12: Part List for Robot

Parts List Qty Description Function

1 Outer Right Panel support structure

1 Outer Left Panel support structure

1 Inner Right Panel support structure

1 Inner Left Panel support structure

1 top support Panel support structure

2 vertical panels store electrical components

2 horizontal panels store electrical components

2 diagonal compartment plates store electrical components

4 suspension part house the sprockets and support sprockets

2 suspension part housing create a joint between the chassis and suspension

2 motor housing part support the motor

2 rubber housing used to dampen vibration support and reduce vibration

2 Electrically Driven Motors Drive Robot

2 12 volt batteries Power Robot

6 1.130 inch diameter idler sprockets Tread system

2 4.99 inch diameter guide sprockets Tread system

6 2.11 inch diameter drive sprockets Tread system / drive train

2 1/2 inch shaft axel for robot

6 3/8 inch shaft used for idler sprockets

12 10-24 machine screws to join the vertical and horizontal panels, and motor housing to the motor

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6.5. Construction

Table 13: Nomenclature used for construction

Nomenclature

Symbol Description SI Units

AS Surface area ft2

DIA

Nominal Diameter of

drill(inches)

in

d Depth of Cut (inches) in

Length Length of part (inches) in

Width Width of part (inches) in

Depth Depth of part (inches) in

FPT Feed per Tooth n/a

FPR Feed per Revolution n/a

IPM Inches per minute in/ min

RPM Revolution per minute n/a

SFM Surface Feed per minute Surface feet/min.

TPI Threads Per inch n/s

Initial considerations for construction was based on a full sized prototype of the robotics

system. With full sized model in mind the construction process was planned to commence with

the manufacturing of the larger plates of the robot, reducing cuts to allow for minor alterations.

Given the new size of our design being a 35% scale of the original design the initial construction

plan needed to be altered in order to conform to our new needs. Ideally our construction would

begin similar before with the construction of the chaise however due to the smaller form factor

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the available hardware did not exactly conform to our prototype scale and the new chaise would

need to be modified first. Our initial construction process begins with the compiling of essential

materials and components. The initial components that were purchased where the battery, motor

and speed controllers. While the components where being ordered the first step of construction

was the obstacle which consisted of climbing a stair case and being able to traverse across

alteration surfaces. As shown in figure 32 building the stair case first consisted of creating a

template and figuring out what dimensions to use. As stated in the earlier paragraph since the

robot was scaled to a reduction of 35% the stairs needed to be scaled down as well. Using the

building codes for a residential stair case the average height is 7.75 in, depth of 10 in width of

37.8 in of each step the team was able to find the scaled value of 3.5 in depth, and a height of

2.715 in and width of 12.6 in. The angle is 39.032 degrees for the overall angle of the stair case.

In figure 34 and figure 35 illustrate the fabricated and completed stair case with an overall length

of 42 in and an overall height of 34.05 in. The overall area of the table is 3ft2.

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.

Figure 32: Installing each of the support blocks for each side

Figure 33: Setting up each of the steps

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Figure 34: Completed stairs and assembly not including table

Figure 35: Completed stairs and table front view

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Figure 36: Completed stairs Isometric view

While the stair case was being built the drawings of the outer and inner panels where

under review by the Engineering Center machine shop and a Water Jet vendor. The cost to

process the panels through a CNC machine was an estimated $1750.00. This CNC cost included

the material, setup and tooling cost. The cost to water jet the panels leaving out features which

required Machining do to the step profile was an estimated $300 for all the panels. Additionally

the motor receivers and the additional required machining estimated $250. The net savings for

first water jetting provided a net savings of $1200.

Figure 37 illustrate the water Jet facility. Water jet works by placing the sheet material from

0.125 in to 6in on a bed and allowing water at a high pressure to cut through the material

providing the required 2-dimensional profile. Figure 38 illustrates the appearance of the panels

after a post process from the water jet.

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Figure 37: Water Jetting Facility

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Figure 38: Inner and outer plate’s appearance after Water Jetting

Once the panels had been processed by the water Jet, the panels where processed by the

engineering manufacturing center. This was a necessary CNC construction to create a housing

for the motors and slots for the supporting members of the robot. All CNC manufacturing was

done on the Fadel Vertical CNC machine as shown in figure 39. The panels are shown in figure

40, notice the step down and the flanges around the motor receiving area. The Ideal method used

for manufacturing is by initially using a large flat end mill to remove a majority of the feature

then once the material has been removed a smaller flat end mill would be used as a final sweep

along the profile to remove and create a final finish. The battery and all slots where created using

a high speed steel flat end mill. The flat end mill tool is shown in figure 40. Note the preferred

method to construct the panels and other mating components would be a combination of CNC

and Water Jet.

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Figure 39 (Fadel CNC Milling Machine [32]

Figure 40: Flat end mill used for CNC manufacturing [33]

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Figure 41: Appearance of Inner and Outer Panels after CNC operation

Figure 42: Appearance of Motor Receivers after CNC operation

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Once the panels where completely finished and all CNC required features were

manufactured the following components of the Robot could be fabricated: Sprocket and bearing

press fit, drop plates, top plate, bottom plate, suspension, and tread. Primary manufacturing

equipment used to fabricate the additional pieces where the knee mill or manual mill, drill press,

lathe, vertical band saw, horizontal band saw, and a bench grinder. A manual mill unlike a CNC

mill which can be operated through a program requires the operator to calibrate the part on the

table of the equipment and adjust the position relative to the drill using the 3 axis table feed hand

wheel. Since the material being used was aluminum the spindle speed RPM of the tool would

need to be rotating at 2200 RPM. The SFM unlike the CNC was controlled by the lever arm and

would be operated using a line of sight method. For aluminum it is best to set the spindle speed

to above 2000 Rpm and for steel from 700 to 1000 rpms. [34] The Manual mill Bridgeport is

shown in in figure 43 and the drill press is shown in figure 43 as well. The lathe and reamers are

shown on figure 45 and figure 46 respectfully. The reamers used for the drill press are based off

the measured Outer Diameters of the Bearings, the standard rule is that for any press fit

application the part fit needs to be -.001 or -.0005 smaller than the part being pressed in the

housing. In the case of a press fit bearing into the sprocket, the sprocket inside diameter needs to

be -.001 or -.0005 smaller than the outer diameter of the bearing. In order to achieve this the

sprockets need to be drilled using a standard drill and then the feature needs to be reamed to

achieve the -.001 or -.0005 smaller than the bearing. For the idler sprockets and smaller

sprockets the reaming sizes are .6220 and .6225 inches for an outer diameter bearing of .623 and

the drill is 19/32 inch. For the larger sprocket the reamer is .7470 and .7475 for an outer diameter

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bearing of .748 and the drill is 23/32. The tread system was constructed using timing belts and

K-1 tabs which allow the belt and chain to move together around the sprockets. The timing belt

and K-1 tabs are joined using rivets which can be shown in figure 50. In order to keep all the

holes aligned with the timing belt the team created a fixture which held the belt in place while

providing drilling locations allowing for precise placement of the rivets once the holes had been

drilled.

Figure 43: Knee Mill on the left side Drill press on the right Side

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Figure 44: Knee Mill Machining features on sprocket

Figure 45: Lathe used to create holes and create press fit

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Figure 46: Reamer tools used to create press fit

Figure 47: Vertical Band Saw [35]

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Figure 48: Horizontal Band Saw [36]

Figure 49: Bench Grinder [37]

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Once the additional components were fabricated the next step was assembly of the

hardware and other components the boxed aluminum was constructed by first bieng cut by the

vertical band saw then bieng smoothed out by the bench grinder. E clips where mounted to the

shafts to prevent the axles from displacing themselves from the initial position. saw then bieng

smoothed.out by the bench grinder. E clips where mounted to the shafts to prevent the axles from

displacing themselves from the initial position. Another way of joining members to each other

was by using threading hardware the threads used for the robot are 10-32, 4-40, and 5-40. The

convention of the hardware is that the first number represents the size of hole and the second

number signifies the number of threads per inch. All of the hardware bieng used on the robot

uses english units however there are similar metric hardware that can be on the robot. The thread

sizes were chosen and based off of the geometrical clearances for the tensioner and the mounting

slots. Note all threads are engaged with a maximum 0.5 inches. The components that required

threads are the tensioner shaft, the inner panels, the vertical and horizontal panels, and the top

and bottom plate. An additional emergency switch panel was installed and used 10-32 threads.

The following figures 52 through 54 illustrate the progress from initial chassis up to the final

assembly of the figure.

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Figure 50: Tread Jig

Figure 51: Tread Chain K-1 Tabs

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Figure 52: Chassis of Robot not including bottom and battery housing plates

Figure 53: Chassis of robot including bottom battery housing plates

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Figure 54: Final assembly with batteries and additional components except the suspension

Figure 55: Assembly without motors and tread system)

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Figure 56: Final side assembly without outer panel

Figure 57: Complete assembly of Hazmat Reconnaissance Robot

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7. Testing and Evaluation

7.1. Testing and Evaluation

Overview

The following sections will evaluate the performance of the HAZMAT ROBOT through the

objectives and develop experiments that will validate the theoretical analysis. Each of the

objectives to be under review will be Robotic system that can operate under hazardous

conditions such as if the robot is able to complete the tasks and how efficiently. The speed test

will compare the robot time against the time it takes for a member of the fire department to

complete the similar task whether it be preparation, stair climbing testing, towing capability, and

battery capacity. For evaluation of the equipment personal must successfully be able to assess the

situation based solely on the visual feedback. The sections being discussed will be: Design of

Experiments, Test Results and Data, Evaluation of Experimental Results, and Improvement of

the design, followed by Discussion.

7.2. Design of Experiments – Description of Experiments

The following section will provide each of the Experiments conducted for the Robot and

will include a description and will evaluate the objective of each experiment. Each of the

experiments reflect the overall behavior and performance of the robot. When conducting the tests

shown below the robot provided the highest difficulty when attempting the stair climbing test.

We through various configurations and reexamination of the geometrical assembly of the robot

the team was able to find a solution and will be further discussed in the stair climbing test

section.

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7.3. Towing Test

This test will evaluate towing capacities of the robot. For this test the robot was submitted to

an extreme condition which is when the surface of the plane is wetted. When discussing the

towing capabilities of the robot it is important to note the placement of the connecting member

and note the terrain where the towing took place. For testing purposes there are 2 surfaces that

where explored. The surfaces are a grass surface and a wetted concrete surface. These surfaces

where chosen for the test because the surfaces represent a low coefficient of friction, specifically

Rubber on grass is roughly 0.35 for car tire on grass. [38] For rubber on wetted Concrete the

coefficient is roughly .45. [39] The following table 14 illustrates the Experimental maximum

towing capacity of the robot when travelling on grass and wetted concrete surface. As expected

the when a lower coefficient of friction the robot would only be able to tow roughly 39% less

than when the robot is on a concrete surface. Theoretical values where based off of the nominal

motor specifications and through the torque and radius of the drive sprocket along with

approximate friction coefficients mentioned earlier the theoretical max weight can be calculated.

The error shown reflects the inaccuracies of the friction coefficient. The motors are not geared

and have continuous torque of 100 in-lbs. per motor giving both motors 200 in-lbs.

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Table 14: Towing Test Results

Towing Test Results

Surface Experimental Max Weight

(lbs.)

Theoretical Max

Weight of both

motors (lbs.)

Error %

Wetted Concrete 60.5 100.35 40

%

Grass 36.5 78.05 53

%

Testing Weights

Weight of Robot (lbs.) 47.5

Weight of Net Blocks(lbs.) 60.5

Weight of Individual cinder Block (lbs.) 36.5

Weight of half of cinder Block (lbs.) 24.0

Figure 58: 60.5lb. Cinder block on Concrete

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Figure 59: 36.5 lb. Cinder Block on Concrete

7.4. Battery Consumption Test

When considering the Battery Consumption test there are several significant factors to

consider and too compare against. The test will not only compare to the theoretical value of the

battery life but will also compare again the required time necessary for the fire department.

Through testimony of the firefighter personal the necessary time of preparation before entering

the hazmat scene is 30 minutes. In order to meet the requirements of the firefighting personnel a

safety factor of 2 was applied to allow an additional 30 minutes for the Hazmat response team to

deploy the robot and gather data of the scene. The following table 15 illustrates the experimental

run time of the robot. The run time gathered included variable loading and simultaneously

included traversing over all terrain surface. Theoretical run time used the analysis from section 5

including the use of one battery which would provide a run time of 21.3 min. The use of 2

batteries would provide a run time of 42.6 minutes which is very conservative value. The

associated errors shown may be caused by not considering the time load acting on the battery.

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Ultimately the robot will have periods of loading and unloading of current which would depend

on the operator and the environment. The robot successfully was able to operate within the 60

minute time frame and would continue past the hour requirement.

Table 15: Battery Consumption Test

Battery Consumption Test

Path of travel Experimental

time Theoretical

time

Required Time to

meet objective

Factor of Safety

all terrain travel(with weight along with variable loading) > 60 min 21.3 60 min 3

7.5. Speed Test

The purpose of this test was to find out how far the robot could travel once deployed in the

field. As shown on table 16 the test was conducted on a wetted concrete surface with no

additional weight being applied. As the table shows the Experimental speed is 0.33ft/s. This

value was calculated by timing the robot travel 10 ft. The Theoretical value was 0.29 ft/s. The

theoretical value is calculated through the different sprockets and using the different ratios of

teeth as a factor to reduce the initial speed of the motor. The analysis for this relationship is

shown in section 5. The following columns illustrate the percent error and net distances for 30

minutes and 60 minutes respectively. The reasoning behind the error can be caused by various

issues first by human error because a team member would initiate the timer while another team

member was moving the robot. Another issue this would be due to the surface of travel if the

surface provided a lower coefficient of friction the speed value acquired may have been closer to

the theoretical value. The usefulness of the net distance travelled would be in the case were the

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square footage of a facility is known the Hazmat unit would be able to determine whether the

Hazmat Robot could be utilized. The average person can walk 4 feet per second however the

robot with equipment and proper safety equipment this value may vary. [40]

Table 16: Speed Test Results

Speed Test Results

Surface Experimental Speed (ft./s)

Theoretical Speed (ft/s)

Error %

net distance in Feet to travel in 30 min

net distance to travel in 60 min

Wetted Concrete no weight 0.33 0.29 14% 521.43 1042.86

7.6. Stair Climbing Test

Upon final assembly of the robot the robot was not able to traverse the stairs in the original

configured position. This issue was mitigated using counter weights. The counterweights acted to

level the robot from the front and ensure the robot does not tip over. The method of setting up the

test was by mounting rails and placing the various weights on the rails. The robot was able to

ascend the stairs with a 12lb weight with difficulty. Through observation a design change would

be to adjust the rear arm and elongate it in order to span the robot over 3 steps instead of 2 steps.

Other suggestions were made to redesign the tread system in order to achieve more traction. The

final suggestion was to elongate the overall chassis to allow for the robot to pivot on the step.

The following table 17 illustrates the various configurations and whether or not the configuration

was able to traverse the stairs. The following figures: 61-63 shows the configuration of the

weights placed 12.11 inches from the center of mass in the positive x-direction and 2.50 inches

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in the positive y-axis. Using the formula, center of mass the center of mass for the various

weights can be calculated.

Figure 60: Distance of weight relative to center of Mass

(𝑋𝑖𝑛) =𝑚1𝑥1+𝑚2𝑥2+𝑚𝑛𝑥𝑛

𝑚1+𝑚2+𝑚𝑛 (Equation 1 Center of Mass equation)

Table 17: Stair Climbing Test

x y z

no wieght mounted at top -0.03 -0.13 0.53 no

5lb wieght mounted at top 1.15 0.192 0.53 no

10 lb weight mounted at top 2.105 0.351 0.53 Yes

12 lb weight mounted at top 2.441 0.407 0.53 Yes

Stair Climbing Test

Ability to climb

Yes or no

Center of Mass Relative to geometrical

originConfiguration

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Figure 61: 5lb. counter weight

Figure 62: 10lb. counter weight

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Figure 63: 12 lb. counter weight

7.7. Improvement of Design:

Through testing of the system and evaluating the various components of the design there are

several adjustments which may be made to increase the performance. With the regards to the

power system the batteries would be ideal for the system and provided a run time which satisfied

the required time. The motors aside from the torque which meets all necessary requirements. The

motor however may be geared in order to increase the speed to meet the average walking speed

of a person. The design may be modified in order to shift the center of mass further toward the

front to allow for smoother stair climbing. Other Ideas which may be able to allow for the robot

to stair climb would be by elongating the rear leg and extending the tread. Making these

modifications would shift the pivot point of the system and allow for the thread to pass over all

of the steps.

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7.8. Discussion:

The following sections illustrated testing done to evaluate the robot. The robot did pass the

battery consumption test, towing test, and speed test. The robot in the original configuration did

not meet the stair climbing test. In order to meet the stair climbing test the center of mass of the

robot needs to be adjusted towards the front. The tread motors and other components

successfully perform and the robot can be deployed through a variety of industrial areas which

contain minimal debris environment.

8. Design considerations

8.1. Health and Safety

With the final state of the completed prototype there is much to be considered for the

environment that its full-scale counterpart is designed to endure (water, heat, and hazardous

chemicals). This does not mean the concept did not take these into consideration, but were not

implemented for cost and time reasons. The main health and safety concerns with this robot

brake down into two categories, the platform and the operator.

For the operators the main concerns involve the maintenance also the hazards and

contaminants that come with the robot has completed its objectives. The robot as designed is

believed to make to allow for relatively easy maintenance for the battery, tread, and for most

components that have possibilities for breaking down. However, many of the operations would

require many tools and the assistance of at least one other individual, adding to that the final

design considers a robot that weighs close to 90 kg (200lb). It is important that further research

can go into this aspect of the design as to make it more accessible to smaller hazmat crews the

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ones who may find the most utility of this robot. With the prototype design some of these

features were implemented for our use and to improve the testing operations, including the tread

and batteries. The biological hazards were not considered with the prototype design this was a

decision made due to the lack of ability to test these parameters and the dangers that could come

along with it. However it is a concern that has been considered, the use of materials that are

resistive to hazardous chemicals or materials with high decontamination properties in order to

avoid the spread to the operator when in contact with the unit. Furthermore the design also shows

the use of compartmentalizing key components with specialized filters to avoid internal

contamination.

For the prototype it does emote a fair amount of safety features that were desired for the

full-scale design. These features include a strong build quality which can handle large loads and

emergency electrical fuses and switches this can be seen the figure 64. The fuses allow for the

maximum amperage to be limited in the event that an excess of current is being drawn. The fuse

will pop and disconnect itself from the circuit avoiding any harm to the motors and the speed

controllers. As well the batteries that were selected for this prototype design are fire retardant

AGM led acid batteries the safest and most efficient of the led acid batteries. Although these do

serve as important safety functions others such as waterproofing, thermal resistance, as well as

making it to hazardous chemicals, which could fatigue or damage key structural components.

Some of these features as stated were not implemented into the prototype design in order to

reduce cost and manufacturing time.

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Figure 64: Left Fuse that has been popped, Right Fuse in good condition [41]

The obvious safety concerns with having this as an emergency tool for HAZMAT

firefighters is the many conditions that this system can be placed in. It is not unreasonable to

assume a situation where this unit is in a scene where it can be raining heavily. The design would

require a waterproof seal in order to prove useful in all scenarios of a HAZMAT firefighter. This

quality was considered similarly to the resisting contaminates to the robot with isolating the key

components to the outside environment. This system allows the units to avoid any contact with

any harmful material effecting the operations of the internal components.

Thermal resistance for robot is an objective that did not take much concern however

could definitely improve the usability of the robot. At the current time the robot can handle a

limited thermal range based on the environments where testing occurred; however was not tested

to work in a condition similar to one in a burning building or frigid environment. Although, it is

reasonable to suspect that our current prototype could handle large amounts of heat from the

choices of aluminum panels and tread built from timing belts only limited really to the plastic

components and the cooling of the electrical components.

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8.2. Assembly and Disassembly

As discussed before in the previous sections the assembly and disassembly is a major

concern with the prototype and the final full-scale design. As for the design aircraft frames

inspired the design of the chasse where the exterior contains the shell and the supporting

structure for the system. This allows for minimum material to be needed and allows for a strong

rigid frame. For the Assembly process of our design is quite simple with 4 major panels with

branch together with a few interlocking panels. Do the limit of our time to design and

manufacture the robot most of the sections connect through the use of 10-32 screws instead of

mechanisms that do not require the use of a tool. It is ideal that the assembly as well as the

disassembly of the robot could be built in this manor for ease of maintenance as mentioned.

For disassembly of the robot the following procedure displays the steps required to obtain

accesses to sprockets and tread.

Figure 65: Illustration of removal of side panel for tread maintenance

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As seen in the figure above the process of getting access to the inner components are

simple. By first unpensioning the tensioner at the yellow circle and by removing the screws in

red the side panel can be removed. Once the panel is removed access to the tread, sprockets and

suspension. This is seen from the figure 66 where the tread has already been removed and other

internal components can be seen.

Figure 66: result of removing side panel and tread system

As seen minimal effort is needed with prototype design, which was intended to allow for

our different testing needs. The full size version of the design however would not be as straight

forward with the implementation of waterproofing. All though implementation of simple/tool

less would be greatly utilized, some examples of these systems are wing nuts, secure latches, and

cotter pins as seen in the figures.

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Figure 67: Wing Nut [42]

Figure 68: Latch [43]

Figure 69: Hairpin Cotter Pin [44]

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8.3. Manufacturability

The robot was designed have a generally simple design. The prototype was constructed

using some basic manufacturing techniques, as well as some more complex. For manufacturing

the processes of water jetting, knee mill, lathe and a CNC for the more complex work. Overall

the design does have a high manufacturability with the proper machinist. To help with the

manufacturability the design also does not call for a low tolerance that can be seen within the

engineering drawings.

8.4. Maintenance of the System

Regular Maintenance

Do to the fact that this device would be in place with an emergency unit of the firefighter

division proper maintenance serves an important protocol to ensure functionality in a hazardous

environment. The general systems that would require regular maintenance in day-to-day

operations would be the batteries, treads, and communications systems. The batteries due to the

large capacity will more than likely be replaced rather than being charged for reduced down

time. As well, depending on different battery technology used in the system may need inspection

after a given amount of cycles. For the prototype design the batteries used are Absorbent Glass

Mat Sealed led acid, which degrades close to 20% of its maximum capacity in a six-month

period seen in figure 70, an extremely important aspect that will affect its usability. The tread

system is another system that can see regular maintenance, this one depends more on the use

case of the system depending tasks that are being asked to perform. Similarly to tiers on a care

the treads of the robot are designed for a limited amount of uses before they begin to ware out.

The final regular maintenance would be under the communication systems this is important

process in order to ensure communications do not fail or effect the task assigned to the robot.

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Figure 70: Shelf life of Selected Battery Power Sonic PSH-1280 [25]

Major Maintenance

As for major maintenance of the system there is only two sources that could be

considered major maintenance which are motor and structural failure. These are both

possibilities that are very detrimental to the system. In these cases the system will be under

severe down time and not usable. In this highly unlikely case the robot would require a complete

tear down in order to obtain access to the effected components. In the case of the motors besides

the replacement of the motor, diagnostics are also required to determine the root cause of the

issue in order to take the appreciate actions. In the other case scenarios with structural damage is

taken on the system more steps will have to be taken do to the range of possibilities that can take

this definition. This kind of maintenance requires a close inspection of the effected components.

Following this inspection the process of remanufacturing certain panels and the replacement of

components damaged.

8.5. Risk Assessment

Do to the nature of the tasks of the Robotic system that is being designed there are many

risk factors that need to be taken into account. Not only do these risks apply to the robot itself but

in extension any person coming into contact with it after performing a HAZMAT task.

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Depending on the situation at hand the risks can be moderate to severe exposer to different

contaminants. It is important that Further research can go into the design of the material that will

be in direct contact with the contaminants in order to prevent expositor outside of a given hazmat

sight.

Aside from threat of unwanted contamination being unknowing transported with the

robot, there are risks specific to the robot in the environment. From questioning HAZMAT

fighter fighters “You can never be certain of the situation you are entering”, it is important to

expect the unexpected. The conditions for the robot can very and without extensive testing with

different materials and contaminants the reaction between the two is unknown. Certain measures

can be accounted for, in the case for flammable gas where only a spark is needed to ignite a

flame all electrical components need to be isolated and protected. The terms used for these kinds

of devices are intrinsically safe. Without the validation of testing it should be labeled as a risk for

all participants.

9. Design Experience

9.1. Overview

The following section will discuss several areas of the design. The areas of the design will

involve: standards being used, Contemporary Issues, Impact of Design in a Global and Societal

Context, Professional and Ethical Responsibility, Life-Long Learning Experience, and

Discussion. Some the standards being used are building codes, OSHA standards which will

incorporate various chemical preventative codes, and health safety regulations. The robot will be

able to function locally and globally which will require different maintenance ability depending

on the country. A contemporary issue which may be relevant to designing a robot is how the

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robot is being used however the current application the robot will not be used in defense. The

Impact of the design in a Global and Societal Context may be considered to be an instrument

used to aid in the fire departments or other associated department in order to facilitate the data

gathering by involving the SI units and meeting relatable installation requirements. The Robot

would need to meet and abide by all professional and ethical responsibilities. Through the design

of the robot experiences with team work collaboration and time management have been gained

and can be applied to future projects.

9.2. Standards used on the project

Codes followed by OSHA standards, international building codes, and Department of

Transportation codes. Chemical safety codes from GSA or (General Services Administration)

agency. The following codes that need to be followed are shown below:

DOT - Department of Transportation; Hazardous Materials Regulations 49 CFR 100-180;

Occupational Safety & Health Administration (OSHA) in 29 CFR 1910.1200

GSA in FED-STD-313;

Other codes are mentioned earlier in the report are shown in section 1.4 of the report.

The first code 49 CFR 100-180 mentioned classifies Occupational safety & Health protocols and

Procedures. The code 29 CFR 1910.1200 involves Hazard communication and to guarantee the

labeling and classifications of chemicals and storage. The last standard being discussed is FED-

STD-313. This code is the Material safety Data, Transportation Data, and Disposal Data, for

hazardous materials [45]

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9.3. The contemporary issues

Contemporary which may arise from the construction of the hazmat robot would be the

concern of a robot to completely replace a human hazmat personnel when in a hazmat situation

arises. This issue has been very prominent in media and there much controversy to which

limitations and constraints need to be put in place. However for this construction and build our

intentions are clear that the robot will be solely used as an instrument for the hazmat personal to

facilitate data gathering and enter areas which are not suitable for the fire department personnel.

Do to the unpredictability of the scene it would be of greater benefit to allow for user control to

operate in the scene. Another reason would be lack of decontamination which would be used for

certain environmental scenarios. Some important aspects to consider from Robots taking the

place of humans would be from an economic and political stand point. When discussing the issue

of the economic stand point with the use of automation researchers have not seen the product

increase which would go against the intuition. The reason for this is due to the fact that since the

employees are the driving force behind production through purchasing power. The increase in

automation will decrease the amount of personal holding jobs and will ultimately decrease the

amount of supply by the companies. From a political stand point this issue the new policies

would need to reflect how the robotic inventions are utilized and determine how much of an

influence this should make on society including schools and other municipal agencies. [46]

Another Contemporary issue which may arise may be controversy when the robot is being

utilized for defense purposes. Do to the modularity of the robot, the robot would be very feasible

to attach weapons or reconnaissance equipment to the platform. The objective of the robot

however is to only be used in public health and safety and should not be used for the purposes of

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defense or warfare. All requirements of the robot are for the Hazmat Robot are to meet the

Hazmat branch of the fire department and are to meet there needs. [47]

9.4. The Impact of the design in a global and societal context

The Impact of the design in a global society would impact various countries in a positive way

and provide additional safety measures for the fire department and other related departments

involved and acting on the hazmat scenarios. One way of facilitating the various countries would

be by following the international building codes. Another way would be to convert and use both

units which can be utilized in the manufacture of the robot for manufacturing purposes. In

different areas of the world different countries may be limited by manufacturing methods and

practices. The maintained will be universal in the protocol and all tools necessary for assembly

and disassembly will be included. [47]

9.5. Professional and Ethical Responsibility

The following ASME (American society of mechanical engineers) code of ethics of

engineers and the National Society of Professional Engineers Code of Ethics for Engineers will

be used to illustrate the ethical responsibilities of the Hazmat Robot. In regards to the robot some

of the ethical responsibilities will be to ensure the welfare and public health are takin paramount

and held in the highest regard. This responsibilities is explained as the first fundamental principal

of the code of ethics of engineers. Another responsibility of the engineer is to consider the

environment. By considering the environment one can ensure the safety of the land and animals

associated are not harmed. In the case of the robot the robot is powered using electricity and seal

lead acid batteries as power source which will be exposed of using environmentally safe protocol

and the metal and rubber will be able to be renewable assuming there is no contamination from

the hazmat scene. [48] If the robot is contaminated then the material must be decontaminated

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using a third party company with the resources to decontaminate panels and various components

.From NSPE (National Society of Professional Engineers) we will not falsify or permit

misrepresentation of the project and robot. The Robot will abide by the functions and regulations

set forth by the fire department. [49]

9.6. Life-Long Learning Experience

Experiences gained from the project include manufacturing practices, design

management, and logistic and communication skills. Manufacturing practices gained through the

project are water jetting application and cost which would be associated with the size of the

design. Additionally another aspect of water jetting would be whether to purchase the material

through a third party or directly through the water jetting company. By comparing the cost of

CNC (Computer numerical Controlled) manufacturing too water jetting the cost will show that

for 2 dimensional cutting water jetting would be a lower cost than to CNC the part. Along with

the cost to outsource manufacturing another factor of manufacturing would be fitment of the

parts. Through the experience the team has learned tolerance and fitment practice for aluminum

and steel. Another very important component of the design was compatibility of components

relative to other components. For example if the motor shaft was in millimeters the gear being

put on the shaft needed to be in SI units and this convection would have to be consistent for the

chain riding on the gears. Logistics was important in organizing the shipping and lead time for

the completion of the parts and other miscellaneous components. One logistical dilemma was

when the team was looking for the chain in a number 25 tabs and there was no available vendor

to which the manufacturing needed to be adjusted to accommodate the bigger size tab links. In

order to meet the deadlines, the electrical components where purchased before hand and while

the project was awaiting one part the team was working on another component of the project.

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Finally Communication was a vital and learned experience throughout the project.

Communication was necessary in developing solutions and led to meeting deadlines and

exploring each other’s strengths and weakness as to build from that and work to complete the

project.

9.7. Discussion

The following aforementioned sections discussed the overall importance and impact the

design has made upon the team. The robot when utilized in the application of hazmat

reconnaissance will serve to facilitate the personal in data gathering and will be able to relay the

information to the personal. The team has gained significant growth of communication and

related engineering disciplines such as additional manufacturing practices which could be further

utilized for future projects and applications to come.

10. Conclusion

10.1. Conclusion and Discussion

The current prototype has many inefficiencies, however, that does not bar the platform

from continued research and testing, which will improve the overall concept. The apparatus did

not successfully climb the stairs without modification to the raw concept. At first, we were under

the impression that the toppling action could be prevented by applying counter weight to the

front of the chassis. To test this theory, we constructed a frame of L-Bracket steel and mounted it

to the top of the apparatus. We then marked 1-inch increments on the frame so that the position

of the weight would be known. The goal of the experimentation with the frame and counter

weight, was to determine the required torque about the geometric center, which would enable the

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apparatus to climb the stairs. When it finally did climb up the stairs, it was very laborious and

progress was slow. Furthermore, the additional bracket and counter weight required for climbing

made descending the stairs a precarious task and once again, the apparatus would attempt to

summersault down the stairs. After researching stair-climbing apparatus further, it was noted that

what all similar platforms have in common is the ability to always touch at least two steps for

any single instant in time.

The apparatus does bridge the gap between two steps but while it drives over the nosing

of the steps, there is an instant in time just before it reaches the third step where the apparatus

loses contact with the initial step. The result is that the robot then teeters on the nose of one step,

which shifts its balance to the rear. Now as the robot continues to drive forward with its balance

shifted to the rear, the reaction is that it climbs nearly vertically on the third step and begins to

roll backward on its self.

After recoding this behavior numerous times and slowing down the footage for analysis,

coupled with the knowledge of other similar concepts, it is clear that this current design needs an

increase in the length of the contact area . The current length is 7.5” while the distance along the

hypotenuse of 3 steps is 8.75”. If the rear arm is extended sufficiently such that the contact

length is stretched to 9”, the robot will climb without hesitations and slippage will be minimal if

at all. In addition to the inadequacies of some of the design parameters, some of the components

were manufactured using less than desirable methods. In the case of the suspension arms, either

CNC or water-jet pieces where to be cut and then assembled and welded together. This would

have resulted in strong symmetric components. Such components would have reduced any

deviations of fitment between the halves of the apparatus. Secondly, such components also allow

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for an appropriate knowledge of the spacing requirements prior to their construction. The

necessity for foresight when working with such components cannot be overstated.

These inefficient mechanisms include the suspension, rotating assembly component

selection, and the addition of improved locks and retainers for the rotating assemblies. These

inefficiencies were present due to sizing constraints and the resulting limited availability of

components for the size bracket applied to this concept. If this prototype had been built to at least

50% the size of the real apparatus, a more broad selection of components would have been

available for use. It is also important to note that the budget was a great limitation. In one

instance, one option was selected over the other because it would chop the price in half. Over

time, the less expensive components proved themselves to be of such low quality that it added

difficulty to certain procedures and they eventually broke down.

Despite the difficulties encountered with some of the components and features of the

design, there is still much promise in the concept. The main goal of this scaled construction is to

prove that an apparatus of the size and proportions required for the HAZMAT application would

be able to perform the maneuvers on various surfaces and climb stairs. Although stairclimbing

requires further research, the data acquired, empirical or otherwise, suggests that with proper

modification, the existing prototype will be able to climb stairs. Additionally, climbing stairs is

not the only maneuvering challenge present when operating in a HAZMAT environment. Being

able to transition across different surfaces, perform maneuvers on uneven terrain, and maintain

traction on slick surfaces, are equally important to the task.

The testing conducted with this platform included driving in dense vegetation, rock and

rubble, dirt and mud, concrete (damp/mossy), and most importantly, driving across from one

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zone to another. Transitional driving is important because it demonstrates the ability of the

platform or vehicle to maintain control even though the coefficients of friction on one point of

contact may vary from the other. This condition may be present when driving from the outside of

the active HAZMAT scene to the “Hot Zone” where the contaminants are, and may affect the

traction of the apparatus. This platform performed excellently in these challenges and was

virtually unimpeded by the change in terrain. The torque provided by the motors allowed the

apparatus to drive without being slowed and this makes for a more manageable driving condition

for the operator.

Another important design consideration is that of towing and plowing. From the

researcher’s point of view, it is difficult to state how crucial the ability to move other objects is

to the overall goal of maneuvering in a HAZMAT environment. While interviewing real

HAZMAT Firefighters from the City of Hialeah Fire Department, they were asked how

necessary it would be to know the “towing capacity” of such an apparatus if they had one for

their department. The response was that “it would be a benefit”. The firefighters went on to

describe the difficulty posed to them if they discover an injured civilian which cannot leave the

scene on their own or if one of their Firefighters is compromised and needs to be evacuated

quickly. Such an apparatus would be able to tow a “down” individual using a modified rescue

sled and evacuate them to safety. Additionally, other obstructions may be present which might

impede the progress of the apparatus into the scene, essentially rendering it useless to the

purpose for which it was created: to survey the scene and assist thereafter. The ability to tow and

push other objects out of the path, also allows the apparatus to be used for clearing the path to the

target of the scene so that the human counterparts can reach it with minimal resistance. This

apparatus performed outstandingly in the push and pull testing. In a “worst case” test, the scaled

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apparatus, weighing 47lbs, towed a maximum of 60lbs while driving on a slick concrete surface.

That means that even when traction is compromised, the platform can pull 1.27 times its own

weight.

The platform performed outstandingly in maneuvering, transitioning, towing, and with

slight modifications, will be able to climb stairs as intended. Thus, this design is promising and

further research and development will yield an even better apparatus.

10.2. Evaluation of Integrated Global Design Aspects

From the outset of this project it was understood that a full sized, fully developed,

apparatus could be used around the globe for HAZMAT scenes and environmental cleanup

operations. As more and more countries around the world continue to develop and become more

sophisticated, their reliance on plastics and inorganic materials will increase. As such demand

grows, the likelihood of spillage or mismanagement of such materials will also grow and

necessitate the institution of HAZMAT-Fire Service or other similar organizations. Whatever the

chosen method is, any team which will be dealing with dangerous chemicals and scenes could

benefit from the use of such an apparatus.

This leads to the conclusion that if such an apparatus could be used around the world, it

would be appropriate and even necessary in some cases, to have an alternate version which

utilizes the metric system for all of its geometry and component selection. These components

should have been made using metric units in their prints and design. The purpose for having

components which were already made with these considerations is to make maintenance and

repair of the apparatus much easier in those countries which do not use the English system and in

which procurement of such components, which utilize the English system, will be difficult.

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Another crucial aspect of the overall design is the selection of a power source. Once

again, this component should be of a type which is readily available around the world and is easy

to service. The optimal choice for this component is Sealed Lead Acid. These batteries are made

of solid cells inside of a layered matrix which is then enclosed by the plastic shroud which makes

up the exterior of the battery. This type of battery is very common and is available in a broad

variety of shapes and sizes which makes it an excellent choice for this apparatus. Additionally,

this type of battery is the least expensive when compared to other batteries which utilize more

charge-dense materials. Examples of batteries which would be desirable but would raise the price

of the apparatus substantially include Lithium Polymer (LiPoly), Nickle Cadmium (NiCd) and

Iron Phosphate (FePO4). In the case of the scaled prototype which was built for this project, it

utilizes SLAs with dimensions which are common to most backup battery-surge protectors.

Furthermore, this battery requires no maintenance and only requires the proper charging and

discharging in order to exact the maximum life of the part. Sealed Lead Acid is a great choice for

this application because it uses a sealed construction which leaves only the terminal leads

exposed. These leads can easily be covered and sealed from the environment by using the proper

equipment on the circuit and ensuring that the wires are completely insulated and shielded.

The previous considerations are ample enough that the apparatus is usable by any

Rescue/HAZMAT personnel from any country around the world.

10.3. Evaluation of Intangible Experiences

Throughout the course of this project there were many defining moments which give an

“added value” to the experience thereof. Lobbying for sponsorship support, adaptation of designs

to meet manufacturing methods and flexible design are a few keynotes which made this project

experience unique and fulfilling for the team.

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An integral part of this project which has increased the experience of the team was the

interactions with real world vendors. Many companies were approached for possible sponsorship

of the project. No approaches were made for funding but request was always made from the

position that the donation of components or services would be preferred to financial help. The

companies approached include, Tesla, NPC, Horizon, and Ballard. Tesla was approached for the

possibility of help with regards to the power supply. Either advice for the selection of a power

source or assistance in implementing a circuit which could improve such a power source would

have been helpful. Tesla declined.

National Power Chair (NPC) was approached with the hopes that they might donate the

motors required for the Full-Scale apparatus. Each motor costs approximately $360 and with a

total of 4 on board the apparatus, that represents a sizeable investment; large enough for a sticker

to be placed on the Robot. NPC said they would consider it and sent a sponsorship application

which was filled out and returned. Subsequently, they never responded.

Horizon and Ballard were both approached. Both companies are in the business of

making Hydrogen-Cell Power Supplies. Because the initial goal was to create the full scale

apparatus which had considerable power needs, these companies were solicited with the aim of

using their power supplies for the robot. Based on the four drive motors alone, a maximum draw

scenario could require up to 650 amperes, 162 amperes per motor. Although that number

represents a peak current scenario, the power requirement is still substantial for a 24 volt circuit.

Ballard declined immediately because their units were reportedly too large for use in our

apparatus. Horizon, on the other hand, seemed very keen to the idea but after communicating

over the course of a month, they determined that their units could not be used for this project

because they were unsure if it would work.

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After so many failed attempts of gaining sponsors and after so much time lost, we

resolved to build a scaled prototype and we would now utilize our own funds. From this

experience one truth emerged and the lesson learned is that when you are launching a concept,

potential sponsors will not always view the project in the same light as you, the designer, will.

Despite the difficulty that sponsorship can pose, it is still up to the team to press forward and

continue to try. In our case we decided to back the project ourselves.

Another Valuable lesson learned is that when events outside of your control begin to

affect the project, do not abandon the concept. Instead, seek out other methods for accomplishing

the objectives. Out team experienced such an occurrence with the manufacture of the suspension

components. We had planned to make the suspension arms from flat bar aluminum which could

be either CNC or Water-Jet into the required shape. After waiting two weeks for four different

vendors to return a quote and possibly execute the job, we contacted all of them and none of the

four had even glanced at the prints. Being short for time and requiring the suspension

components that week in order to commence testing, we resolved to use rectangular aluminum

tubing and fabricate the desired shape from various lengths. Within two days, we had fabricated

the necessary components and moved on to fitment of the track.

A very important facet of our experience gained from this project was the realization of

how important it is to make a design modular, especially if it is the first prototype. Our design

had the ability to be adjusted fairly easily. This feature was particularly useful when it came time

to run the robot on the stairs. Because most of the components could be repositioned or locked

by placing a screw, it was very easy to reconfigure the suspension and attempt to climb the stairs

again and again. In addition, most of the springs had similar dimensions, or there was only a

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maximum size which must be considered. This gave us the ability to swap any spring to any

position on the suspension system.

Although many aspects of the project went well, it can be said that there was oversight

with regards to the suspension overall. The system required analysis from different points of

reference and the use of more methods than were applied. For instance, the springs were

determined based on static and dynamic calculations. While the springs did behave in the manner

predicted by the calculations, there was one consideration which was overlooked: the track and

sprockets behave in a manner that more closely simulates a cable and pulley system. Because it

was not framed in this manner, we did not realize that the strength of the motors would pull the

tread to the point that it bottomed-out the suspension. Had the suspension been considered in this

manner, we would have realized that there would need to be additional sprockets to isolate the

drive sprocket from the rest of the system and thereby prevent the direct transfer of force to the

suspension components. To overcome this difficulty, we instead limited the travel of the

suspension arms since they are responsible for the large travel of the suspension. By leaving the

smaller appendages (the feet) free, the apparatus still had some suspension travel.

The most important wisdom gained from this experience is that some processes are long

and require repeated testing and repeated failure in order to achieve success in the future. The

process of design was rigorous though we discovered that it still needs further work and study.

The manufacturing process was laborious but after completing the first prototype it is apparent

where the deficiencies are and solutions are attainable. With all things considered, perseverance

is key.

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10.4. Commercialization Prospects of the Product

In the real world, the difference between ideas that are built and the ideas that are

scrapped is often a combination of market assessment and development cost versus selling price.

In the case of this project, there is a relatively large market for robotic reconnaissance devices.

The key for our project is that it targets a very precise niche in the market. There are a few

platforms on the market which claim to be useable for HAZMAT scenarios but these are all a

retrofit. They were not purpose built for the HAZMAT environment.

Of the apparatuses which are purpose built and have been completed, price is the limiting

factor. The target market does not want to pay $200,000 dollars or more per apparatus. [50] This

is one of the strengths of the apparatus which we have designed; it reduces overall costs on the

initial and production side. Many of the existing apparatus use exotic materials such as titanium

and carbon-fiber while the HRU design utilizes 6061 aluminum and stainless steel. While other

platforms employ special, in-house sensory, the full-scale of our apparatus would allow the

HAZMAT teams to equip and unequip their existing sensors to the apparatus. Furthermore, the

design we have created has virtually zero dangling or extending appendages which may cause

entanglement on the scene. The result is a platform with smooth, easy to clean surfaces that is

robust yet maneuverable, which is what is needed for this field.

There are a few negatives to the design, however, further research is needed to determine

the feasibility of the overall concept. One such attribute is that the suspension needs to be

analyzed and redesigned to perform the full function of climbing as intended. Additionally,

further research into material treatments and coatings must be conducted in order to select the

proper treatment for aluminum and steel in order to prevent contamination, reactivity and

corrosion of the apparatus as it enters a volatile environment.

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Another positive of the design is that once it does reach a developed and marketable state,

the base is an excellent candidate for performing a myriad of other tasks. These alternate roles

include military, law enforcement, large-scale leak or cleanup assistance, mining reconnaissance,

and exploration. Because of the strenuous demands placed on an apparatus by the HAZMAT

environment/problem, it stands to reason that a platform which can function in such a harsh

environment could be retrofitted and used in less demanding environments with even greater

reliability.

10.5. Future Work

As this project draws to a close, it is understood that this was a first attempt to create a

platform which addresses the mobility requirements for entering the HAZMAT environment.

These criteria include the following; perform maneuvers in various terrain, perform maneuvers

on reduced traction surfaces, and to climb stairs with ease. Although not all of these objectives

were accomplished, achievement of these goals and overall improvements to the system are

within reach, even for this prototype. Apart from the mobility aspects, there was a lot of

information gathered about existing technology which may be applied to the full-scale apparatus

and improve its alternate functions.

The most crucial feature, and often a limiting factor for any apparatus, is the power

supply. Scientists and engineers continue to develop new machines and apply technology in

ways never conceived before yet they remain tethered to the laboratory. It is quite evident that

what is needed for the ultimate success and implementation of this and other apparatuses, is a

major breakthrough in power-generation. There are apparatuses that boast relatively high runtime

and standby time but these numbers do not represent actual work in the designated field. In order

for robotics to grow and be applied in their fields, more power is necessary. Some possible

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methods include enhancing circuits so that current draw is regulated, and improving alternative

energy methods by making them more applicable to mobile platforms.

Another aspect of our apparatus which still requires research is the suspension. The

design of this apparatus was approached with the end-goal in mind and this severely limited the

amount of time spent researching the suspension. There are many robotics platforms which

employ tank treads but there is an even greater variety of stairclimbing apparatuses. Among

these, the suspension is often the defining characteristic. Some mechanisms use a type of

“walking” action while others use tank tread and moveable pivot points. This apparatus does not

utilize any appendages nor does it have any independently controlled links within the suspension.

After conducting the testing of the scaled prototype, it became apparent that some type of

independent control would greatly enhance the performance of the drive system. In the case of

the target field for our apparatus however, a simpler system is a better system. Fewer moving

parts translates into fewer crevices where contaminants may cling and fewer possible points of

failure. For those reasons, this apparatus must be designed such that it will climb stairs without

difficulty and without the addition of any cumbersome appendages or addition moving parts.

In order to properly design such a suspension system, a proper kinematic and phase study

must be conducted. This means analyzing the motion of the suspension as a reaction to the

overall movement of the system. The tread system will be considered as a cable and the

sprockets, as pulleys. The points of contact between the steps and the tread will then behave as

pressure points, which alter the tension in the belt up to that point. Apart from changing the

method of analysis prior to the redesign of this vital component, the different scenarios, which

may occur while climbing, will also be brought into consideration.

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A lot of time and effort was spent researching the equipment, which may be needed for

such an apparatus to function in the HAZMAT environment yet none of this information was

applied to this prototype because it was beyond the scope of this project. In the future, even more

research must be conducted with regards to door-opening devices and methods, and forced entry

methods. Only then will we be able to create an arm, which has the right tools for forced, and

non-forced entry. These components should be rested separate of the apparatus and then applied

to the apparatus to test for drivability and end-user functionality.

Lastly, the treads will also need special research and testing in order to ensure that this

component will survive the punishment of a heavy load and exposure to corrosives and other

concentrated chemicals. After material testing confirms the best candidates for coating the

exterior of the tread, further research must be conducted to determine whether or not these

materials can be used to coat a metallic sub structure. This same manufacturing technique is used

in construction equipment and snowmobiles. The result is a rigid structure for bearing the loads

and connecting to the drive sprockets and cogs that still has the grip and flexibility on the

exterior, which is pivotal to the tasks of maneuvering and stair climbing. Overall, there is still

much work needed in order to complete this apparatus but all technology already exists and is

only being reapplied to this unique field.

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127

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128

Appendices

A. Detailed Engineering Drawings of All Parts, Subsystems and Assemblies

129

130

131

132

133

134

135

136

137

138

139

140

141

142

143

144

145

146

147

B. Multilingual User’s Manuals in English, Spanish and French

English Manuel:

148

149

Spanish Manuel:

150

151

152

French Manuel:

153

154

C. Excerpts of Guidelines Used in the Project: Standards, Codes, Specifications and

Technical Regulations

"ASME," 2015. [Online]. Available: https://www.asme.org/about-asme/standards. [Accessed 23

11 2015].

"ISO," 2015. [Online]. Available: http://www.iso.org/iso/home/store/catalogue_ics.htm.

[Accessed 23 11 2015].

"Energy," 2015. [Online]. Available: http://energy.gov/ehss/services/nuclear-safety/department-

energy-technical-standards-program/doe-technical-standard. [Accessed 23 11 2015].

"ASTM," 2015. [Online]. Available:

http://compass.astm.org/CUSTOMERS/search/search.html?query=astm&dltype=allstd&bossecti

on=03. [Accessed 23 11 2015].

I. B. CODE, "INTERNATIONAL BUILDING CODE," CHAPTER 10 MEANS OF DEGREES

SECTION 1008.1.1 IBC INTERPRETATION NO. 05-05, pp. 1-2, 2003.

https://www.asme.org/about-asme/standards

http://www.iso.org/iso/home/store/catalogue_ics.htm

http://energy.gov/ehss/services/nuclear-safety/department-energy-technical-standards-program/doe-technical-standard

http://energy.gov/ehss/services/nuclear-safety/department-energy-technical-standards-program/doe-technical-standard

http://compass.astm.org/CUSTOMERS/search/search.html?query=astm&dltype=allstd&bossection=03

http://compass.astm.org/CUSTOMERS/search/search.html?query=astm&dltype=allstd&bossection=03

155

"CODE OF ETHICS OF ENGINEERS," ETHICS, p. 1, 9 10 2007.

N. S. o. P. Engineers, "Code of Ethics for Engineers," Code of Ethics for Engineers, p. 2, July

2007.

D. Copies of Used Commercial Machine Element Catalogs (Scanned Material)

156

157

158

159

160

161

162

163

164

165

166

E. Detailed Raw Design Calculations and Analysis (Scanned Material)

Figure 71: Force hand calculation page 1

Figure 72: Force hand Calculation Page 2

167

Figure 73: Force hand Calculation Page 3

Figure 74: Suspension designs

168

Figure 75: Suspension Hand Calculation Page 1

Figure 76: Static Suspension Hand Calculation Page

169

Figure 77: Bearing Free Body Diagram

170

Figure 78: Static analysis of robot on incline

171

Figure 79: Dynamic analysis of robot on incline

172

Figure 80: Analysis of robot climbing stairs

173

Figure 81: Minimum power requirement for stair climbing

174

Figure 82: Motor comparison for full size design

175

Figure 83: Battery and stair sample hand calculations

176

Figure 84: Stair Construction Calculations

177

Figure 85: component dimensions Page 1

178

Figure 86: Component Dimensions Page 2

179

Figure 87: Component Dimensions Page 3

180

Figure 88: Machinability component Mach set up

181

Figure 89: component suspension dimensions

182

F. Project Photo Album

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TEAM 14 -HAZMAT ROBOT FINAL REPORT

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