Fall 2006

Advisors Client Dr. John Lamont Iowa State University Professor Ralph Patterson III Department of Electrical and Computer Engineering

Primary Vehicle Team Secondary Vehicle Team

2nd Semester 1st Semester 1st Semester Tim Gruwell (Team Leader) Brian Baumhover Patrick Turner

Andrew Larson Bai Shen Byung Kang

Erica Moyer Bill Hughes

Maria-Cristina Olivas Hassan Javed Jeff Pries (ME)

Josh Robinson Pankaj Makhija Brett Pfeffer (ME)

Kito Berg-Taylor (AerE)

Gustav Brandstrom (ME)

Interdisciplinary Members

Interdisciplinary Members

Micro-CART U N M A N N E D

A E R I A L

V E H I C L EONGO – 03 Microprocessor–Controlled Aerial Robotics Team

Fall 2006

Presentation Outline

• Definitions

• Acknowledgment

• Problem statement

• Operating environment

• Intended users and uses

• Assumptions and limitations

• End product requirements

• Project activity– Previous accomplishments– Present accomplishments– Future required activities

• Approaches considered

• Project definition activities

• Research activities

• Design activities

• Implementations activities

• Testing activities

• Resources and schedules

• Project evaluation

• Commercialization

• Suggestions for future work

• Lessons learned

• Risks and risk management

• Closing summary

Fall 2006

Attitude The orientation of an aircraft's axes relative to a reference line or plane, such as the horizon

AUVSI Association for Unmanned Vehicle Systems International CAD Computer Aided DesignGPS Global positioning systemGSS Ground station systemIARC International Aerial Robotics CompetitionIMU Inertial measurement unitPC-104 x86-based controllable board PIC Programmable interface controllerPID Proportional Integral DerivativePitch Revolution of a vehicle forward and backward on a central axisPro/E Professional Engineer CAD packagePWM Pulse width modulationRC Remote controlRoll Revolution around the longitudinal axis of a vehicleSV Secondary VehicleUAV Unmanned aerial vehicleWIKI (What I Know Is) A public documentation repositoryYaw Revolution around the vertical axis of a vehicle

Acronym Definitions

Fall 2006

Acknowledgement

Iowa State University’s Microprocessor-Controlled Aerial Robotics Team would like to give special thanks to the following people and organizations for their assistance:

Dr. John W Lamont and Assistant Professor Ralph Patterson III for sharing their professional experience and guidance throughout the course of this project.

Lockheed Martin Corporation for their technical expertise and generous financial contribution to this costly endeavor. Without their assistance this project would not be possible.

The Department of Electrical and Computer Engineering for creating Micro-CART and providing the skills and knowledge required for this project.

Fall 2006

Problem Statement

• General Problem Statement– To provide an entry into the International Aerial Robotics

Competition (IARC) Summer 2007 for Iowa State University

• General Solution Approach– Develop an aerial vehicle to compete in IARC Level 1– Develop a secondary vehicle for higher level IARC– Main system components

• PC-104 embedded system • IMU• GPS unit • Battery power supply• Sonar array• Digital magnetic compass• Wireless modem

Fall 2006

IARC (International Aerial Robotics Competition)• Diverse indoor/outdoor environments• Obstacles defined by the competition mission

• Temperature threshold (60o-100o F)• Possible wind, light precipitation, adverse topography of the

competition location• No extreme environments, e.g. fog, rain, etc.

Operating Environment

Fall 2006

Initial Users• Spring 2007 Micro-CART team members

– Responsible for operating vehicle in summer 2007 IARC

Future Users• Future Micro-CART teams• Researchers• Industry representatives• Hobbyists

Intended Users

Fall 2006

Initial use• Entry into Summer 2007 IARC

Future uses• Search and rescue• Military and law enforcement reconnaissance• Environmental catastrophe control

Intended Uses

Fall 2006

Assumptions • IARC Mission rules may change • Necessary funding remains available • Suitable hardware and software is available at an

affordable price• Onboard computing systems will be sufficient• Current vehicle able to carry necessary equipment• On-board memory sufficient• Sensor system will provide all necessary flight software

inputs• Attachment of secondary vehicle to primary vehicle

Assumptions and Limitations

Fall 2006

Limitations • Physical limits of helicopter• Obstacle detection and avoidance• Power consumption limits• Competition maximum weight limit• Competition requirements• Team member expertise• Weather

Assumptions and Limitations

Fall 2006

Primary VehicleIARC Level 1 Autonomous Functionality• Take off• Navigate to five waypoints with the fifth located three

kilometers away• Maintain a stable hover at the fifth waypoint

Secondary VehicleHigher level IARC Functionality• Communication with Primary Vehicle• Image Recognition• Obstacle Avoidance

End Product Requirements

Fall 2006

Presentation Outline

• Definitions

• Acknowledgement

• Problem statement

• Operating environment

• Intended users and uses

• Assumptions and limitations

• End product requirements

• Project activity– Previous accomplishments– Present accomplishments– Future required activities

• Approaches considered

• Project definition activities

• Research activities

• Design activities

• Implementation Activities

• Testing Activities

• Resources and schedules

• Project evaluation

• Commercialization

• Suggestions for future work

• Lessons learned

• Risks and risk management

• Closing summary

Fall 2006

Project Activity

Previous Accomplishments• Acquired helicopter, system components, and sensors• Flight test stand modifications

Present Accomplishments• First autonomously hovering flight on Sept. 26th, 2006• Sonar developed and successfully implemented• New Lithium Polymer battery purchased• Testing procedures and Pre-Flight systems check list

created

Fall 2006

Previous AccomplishmentsFall 1999• Purchased RC helicopter• Purchased Dell PC

Fall 2000 – 2003• Pilot training program

Spring 2002• Acquired security box

Fall 2002• Acquired and setup Linux PC• Sonar circuit design• Complete PIC programming for serial interfacing

Fall 2002 – Spring 2003• Hardware acquisitions• Serial software development• PIC programming• PC-104+ operating system

Spring 2003• Power system• Mounting platform• Manual override switch

Fall 2004

• Replace PC-104+

• Purchased Dell PC

Spring 2005

• Acquired Wireless Data-link

• Acquired Magnetic Compass

Fall 2005

• WIKI

• Hardware enclosure

• New head block

• Flight test stand modifications

• Flight testing

• Onboard payload limitations

Spring 2006

• Untested altitude flight control code

• Flight simulator software ported to Linux

• Flight test stand modifications

• Developed exhaust shield

• GPS research and replacement

Fall 2006

Present Accomplishments

• Sonar

– A/D RS232 Module

– MINI-A Transducer

• New Lithium Polymer Battery

– Much higher Power-to-Weight Ratio

• New flight control software• First autonomously hovering flight on Sept. 26th,

2006• Testing procedures and Pre-Flight systems check

list created

Fall 2006

Future Activities

Compete in level one IARC• Complete flight control code• Test fully autonomous flight • Research and plan trip to the competition

Fall 2006

Future Activities

Continue planning and development for higher IARC levels

• Level 2– Image recognition

– Object avoidance

• Level 3– Deployment of the secondary vehicle

– Image recognition

– Object avoidance

Fall 2006

Approaches Considered

Activity Approaches Advantages Disadvantages Choice

Flight Control Used C++ instead of C language.

-Object Oriented Programming is easy for modifications.

-Might be slower Accepted

Code Comments on Doxygen

-Nice Layout and it does everything automatically.

Accepted

Writing data to the CF card or to the RF modem.

-Sends sensor logs to RF modem and that in turn sends it to the Ground Station for logging.

-Write Speeds may be limited.

-Might lose packet information.

Accepted

Fall 2006

Approaches Considered

Activity Approaches Advantages Disadvantages Choice

Sonar New circuit design for Sonar

-Do not need the Trigger Circuit and the MUX.

-Implementing a program can retrieve the data from the Sonar.

Accepted

Secondary Vehicle Multi-rotor -More lift capacity -Very unstable Rejected

Contra-rotation. -Fewer components and more stability.

-Less lift Accepted

Fall 2006

Project Definition Activities (SV)

IARC Requirements

- Fully autonomous

- Carried and launched by primary vehicle

- 1m x 1m building entrance

-Safely navigate into the building

- Ability to obtain images

- Relaying images back to ground station through primary vehicle

Fall 2006

Research Activities

Research Aims:• Full understanding of vehicle and component behavior• Minimize wasted development time• Ensure suitability of components

Research Areas:• Existing component performance• Flight control algorithm design• New Topics

– Debugging and Datalogging– Code Documentation– Optimal Control Frequency

Fall 2006

Research Activities

Existing Component Performance

• Operational Limits

• Precision• Accuracy• Reliability• Quirks

Fall 2006

Research Activities - IMU• Operational Limits:

– Missing spec. sheet limits precise knowledge– Assumptions made based on mfg. manual

• ±2g Accelerometers• ±100º/sec Rate Sensors

– Onboard Kalmann filter provides angular position– Temperature Compensated

• Accuracy and Precision– Precision to 0.01º and 0.01m/s2– Angular position, rate and linear acceleration highly accurate

• Quirks– Intermittent failure to initialize– Mounted upside down on helicopter

Fall 2006

Research Activities - Compass

• Operational Limits:– Compass must be level for accurate readings– Cannot operate within 1.5' of main rotor shaft

• Accuracy and Precision:– Lacked accuracy within the test environment– Readings disputed by traditional compass

• Requires in-flight testing to ascertain reliability• Magnetic interference around main rotor shaft

Fall 2006

Research Activities - PC-104

• HESC Power Supply– Produces 5V and 12V power– 6V to 40V input range– High likelihood voltage fluctuations will cause power supply failure.

• Serial Port Add-on Board– IRQ sharing creates massive delays– To achieve parallel data streaming each port must be assigned

unique IRQ

Fall 2006

Research Activities - GPS

• Uses standard NMEA protocol

• Interface has to be reverse engineered from proprietary software.

• Cannot obtain signal indoors

Fall 2006

Research Activities

Flight Control Algorithm• Existing software was written in C and used a multi-

layered approach

• Large quantities of code were missing• Control revolved around a PID

– PID is well-suited to onboard helicopter control– PID was incorrectly and incompletely implemented

• Excessive threading contributed to complexity• Hardware interfaces were buggy but mostly complete• Code translated well to object-oriented design

Fall 2006

Research Activities

New Topics

• Debugging and Data logging– Real-Time In-Flight feedback– New debugging framework– Unit Tests

• Code Documentation– Doxygen

• Optimal Control Frequency– Comparison with other vehicles

Fall 2006

Presentation Outline

• Definitions

• Acknowledgement

• Problem statement

• Operating environment

• Intended users and uses

• Assumptions and limitations

• End product requirements

• Project activity• Previous accomplishments• Present accomplishments• Future required activities

• Approaches considered

• Project definition activities

• Research activities

• Design activities

• Implementations activities

• Testing activities

• Resources and schedules

• Project evaluation

• Commercialization

• Suggestions for future work

• Lessons learned

• Risks and risk management

• Closing summary

Fall 2006

Design Activities

Hardware• New sonar hardware

– Serial I/O Board– New Transducer

• Kill switch• Wiring and mounting of

components– sonar– compass– power supply wiring

Fall 2006

Design Activities

Sonar• Ultrasonic transducer

– Downward facing– 6” to 20' range– Analog signal wired to I/O

Board• I/O Board

– RS-232 interface– Room to easily add up to 7

additional transducers

Fall 2006

Design Activities

Software• Previously existing design

– Old design found to be unimplemented except for basic hardware interfacing code

– Concluded that existing architecture was inappropriate – too much threading added unneeded complexity and overhead

Fall 2006

Design Activities

Software• Defined new architecture

– Simplified, tighter control loop and eliminated unnecessary threading

– Rewrote much of controller code in a cleaner, object-oriented way

– Included integrated debugging and logging module, unit tests, and software emulation of each hardware sensor module

Fall 2006

Implementation Activities

• Divided components among team members• Rewired helicopter

– prevent confusion

• Rewrote flight control code– reuse hardware interface code– control algorithm using PID

• Mounted remaining components

Fall 2006

Testing and Modification Activities

Software Tests• Test individual components with new software• Run software on helicopter• Unit testing• Reliability

– Code does not exhibit any reliability problems

• Error tolerance– Program found to be tolerant of failures in everything but IMU

• Speed Issues– 20Hz decided upon as minimum acceptable speed for control

loop frequency– Hardware limit appears to be ~45Hz

Fall 2006

Testing and Modification Activities

Hardware Tests• check functionality of all components being mounted on

helicopter• check functionality of newly built components• sensor interaction

– IMU initialization and polling code stress-tested– Sensor input tested for helicopter 's full range of motion

Helicopter Control• check servos• have new team members learn controls

Fall 2006

Research Activities (SV)

• Previous Design

• Design Alternatives– Alternative Solutions to IARC Criteria

• Components– Necessary Components– Previously Purchased Components

Fall 2006

Research Activities (SV)

Previous Design

• Function and advantages• Missing documentation• Requirements for

functionality

Fall 2006

Research Activities (SV)

Design Alternatives

• Ground based solutions• Wing-body options• Multi-rotor• Contra-rotation

Fall 2006

Research Activities (SV)

Necessary Components– Size and weight– Integration with other components – Power requirements

• Microcontroller• IMU• Transceiver

– Bandwidth– Range

Fall 2006

Research Activities (SV)

Current Components– Function and operation

• Motors– Power requirements– Integration with speed controllers

• Speed Controllers– Integration within current design– Integration within test stand

Fall 2006

Design Activities (SV)

Test Stand

• Reason: Test lift capacity of contra-rotation.• Design: Floating plate, spring tensioned design.

Fall 2006

Design Activities (SV)

Secondary Vehicle Frame

• Reason: New vehicle concept requires all new layout

• Design: Coaxial, contra-rotating rotors create a design similar to standard helicopter.

Fall 2006

Implementation Activities (SV)

Current Design Status

• Development of chassis CAD models

• Selected onboard components

• Development of test stand before chassis construction

Fall 2006

Implementation Activities (SV)

BladeRunner R/C

Helicopter

• Contra-rotation proof of concept

• Study passive stability system

• Motivated by concerns regarding control solution for current design

BladeRunner commercial model

Fall 2006

Testing Activities (SV)

Previous Secondary

Vehicle Design

• Quad-rotor design presents controllability issues

• Material availability

• Competition constraints

• XUFO test results not promising

• Motivation for design alternatives

Current secondary vehicle design

Commercial XUFO

Fall 2006

Testing Activities (SV)

Contra-Rotation

Test Stand

• Evaluate lift capacity of two motors

• Evaluate stability and yaw control

• Evaluate battery life

Fall 2006

Presentation Outline

• Definitions

• Acknowledgement

• Problem statement

• Operating environment

• Intended users and uses

• Assumptions and limitations

• End product requirements

• Project activity• Previous accomplishments• Present accomplishments• Future required activities

• Approaches considered

• Project definition activities

• Research activities

• Design activities

• Implementations activities

• Testing activities

• Resources and schedules

• Project evaluation

• Commercialization

• Suggestions for future work

• Lessons learned

• Risks and risk management

• Closing summary

Fall 2006

Resources

• Estimated and actual personal hours• 1223.75 Total Hours• Average 80 hours per team member

Hours Category Estimated Hours Actual Hours

Team Leader 324 254.75

Software Subteam 671 405

Ground Station Subteam 188 140

Hardware Subteam 553 421

Secondary Vehicle Subteam 396 333

Total 2132 1553.75

Fall 2006

ResourcesItem Previous Total Cost Actual Cost for Fall 2006 Total Project Cost to Date

Sensor Systems      

GPS $ 5,000.00 $ 31.00 $ 5,031.00

IMU $ 5,500.00 $ 0.00 $ 5,500.00

Sonar $ 618.00 $ 172.78 $ 790.78

Magnetic compass $ 400.00 $ 0.00 $ 400.00

Wireless comm link $ 500.00 $ 0.00 $ 500.00

Ground station PC $ 0.00 $ 20.00 $ 20.00

Flight Controls    

PC/104 $ 1,217.00 $ 0.00 $ 1,217.00

Servo controller $ 100.00 $ 0.00 $ 100.00

Manual override switch $ 50.00 $ 0.00 $ 50.00

Emergency shutoff switch $ 59.85 $ 0.00 $ 59.85

Vehicle Configuration    

Power supply / battery $ 1,160.00 $ 629.95 $ 1,789.95

Helicopter / maintenance $ 6,437.00 $ 69.00 $ 6,506.00

Flight Augmentation Stand $ 185.00 $ 0.00  $ 185.00

Total Hours 10,771 1,223.75 11,994.75

Labor ($10.50 per hour) $ 113,095.50 $ 12,849.75 $ 125,945.25

Total Costs (w/o labor) $ 21,226.85 $ 922.73 $ 22,149.58

Total Costs (w/ labor) $ 134,322.35 $ 13,772.48 $ 148,094.83

Fall 2006

Schedules

Fall 2006

Schedules

Fall 2006

Project Evaluation

Component TasksCurrent

StatusGPS software Test and verify Incomplete

Mounting scheme Implement, test, and verify Complete

Sonar Purchase, test, and verify Complete

Sonar software Develop, test, and verify Complete

Compass software Test and verify Complete

Wireless data link Test and verify Complete

Flight Control Software Debug, test, and verify Incomplete

Composite enclosureDesign, lay-out, and purchase composite

hardwareComplete

Fall 2006

Project Evaluation

Component Tasks Current StatusAutonomous hover Test and verify Complete

Autonomous flight Test and verify Incomplete

Helicopter electronics Test and verify Complete

Helicopter Determine center of mass Incomplete

Test stand Acquire Complete

Translational flight controller Complete, test, and verify Incomplete

Senior design Update website Complete

Senior design Fulfill reporting requirements Complete

Senior design Document on the Wiki In Progress

Fall 2006

Commercialization

• At this time, the project will not be commercialized– Too large, too fragile for military applications– Too expensive for civilian applications

• Future– Military– Reconnaissance and surveying– Hazardous site clean-up– Search and rescue– Traffic control and enforcement

Fall 2006

Recommendations

• Continue as originally envisioned– Automated helicopter is close to flying– Project will no longer suffer “memory loss”– Micro-CART is a worthwhile learning

experience

Fall 2006

Lessons Learned

• Take care when testing• Document thoroughly• Start deliverables early

Fall 2006

Risk and Risk Management

Risk: Loss of team member Management: • Have proper documentation• Overlapping team member skills

Risk: Damage to components Management: • Create accurate testing procedures• Understand the “Big Picture”

Risk: Personal injury during testingManagement: • Stay alert• Maintain communication

Risk: Lack of expertise Management:• Consult advisors• Research and learn

Fall 2006

Closing Summary

• Project has had it’s hurdles, but progress is still being made and we will be ready to compete in Summer 2007.

• Micro-CART is a challenging project encompassing control systems, mechanical systems, hardware, and software.

• It also gives students an excellent way to broaden their experiences, build problem solving skills, and learn responsibility.

• Bottom Line: Micro-CART is a valuable and interesting project and should be continued in Senior Design.

Fall 2006

Questions?