Design: Clif ReederWebsite: Emil Stefanov

Presentation: Mohit AgrawalCollege Student Advisor: Kyle Ryan

High School Teacher Advisor: Mr. Steve Florence

Design Challenge 1—Drive train solution

Model Landmine Detecting Robot

The Landmine Threat

• There are 40-120 million landmines worldwide today

• Landmines injure/kill about 10,000 every year

• Landmines are long-term killers, active long after a war is over

• Landmines are indiscriminate in their killing of people

Threat-cont’d

• Landmines wreak massive humanitarian problems

• Through the Ottawa Treaty and other measures, less mines are being laid

• Ottawa Treaty: signatories agree to stop using antipersonnel landmines (the most common mine)

The flames represent landmine casualties. The shaded nations have signed/approved the Ottawa Treaty.

Yearly reports documenting the landmine problem worldwide

Challenge of Demining

• Deminers face monumental task in clearing landmines

• Most common method to find landmines is by metal detector

• Dogs, bees, and rats can also find landmines• People will have to go in and still remove the

landmine by hand with a prod• Process is fraught with dangers and long-term

viable demining methods are needed

Detectors are notoriously inaccurate

Hand prodding is very dangerous

RSL Challenge

• Robots Save Lives (RSL) Challenge:– Design, test, and build landmine detection

robot– Criteria:

• 1. Low Cost• 2. Autonomous• 3. Easily Serviced and Maintained• 4. Reuse parts from FIRST kit

Design Challenge #1

• Develop a drive train solution around a Fisher Price electric motor/gearbox

• Create a robot blueprint based off drive train solution:– 1. Low weight– 2. Responds to obstacles– 3. Operates on rough terrain

• Theorize possible sensor/electronic systems for robot

Available Parts

• The Fisher Price motors and their gearboxes are designed for remote controlled cars for children

• The free speed of this motor is around 24,000 RPM

• Gearboxes reduce RPM to about 126

• This gives a final ratio of 190:1

3 ¼”

Fisher Price Motors

7.5”

top

bottom

Gearboxes from kit

Other Parts

1. 5/8th” keyed aluminum shaft to fit in gearbox

2. Adapter to hold the shaft in

3. Plates to attach drive train to assembly

4. Frame made of 20mm extruded aluminum

Other Parts-cont’d

5. 12” pneumatic wheels from 2004 Kit of Parts

6. #35 Nylon chain

7. Lexan for protecting/sheathing robot

8. Electronic/sensor system to run robot and detect landmines

Drive Train

• The drive train will be able to produce x torque or y watts

• The 5/8th” keyed aluminum shaft will extend from the gearbox to the ball bearings

• A specially CAD-ed adapter (hub) will stabilize the shaft

• These ball bearings will connect to the sprockets

Drive Train-cont’d

• These sprockets rotate the chain which drive a pair of wheels on each side of the tank

• Connected to ball bearing and sprocket

• 14 tooth nylon sprockets all around– No additional reduction

Body Design

• Body of extruded aluminum is:– light– manageable– maneuverable

• The design has the wheels extending beyond the assembly

• This will allow the robot to flip around and change course upon running into a large obstacle

• The curved Lexan is a safety precaution to protect the assembly and to ensure that while flipping over, no obstruction gets in its way

Electronics and Sensors

• One speed controller for each dive assembly• One robot controller to run the autonomous

programming• Sensor: Metal detectors or similar

derivatives are very inaccurate• Sensor: “Millimeter Wave Emission

Detector” is a more ideal sensor for this robot.

• The sensor will be mounted downward upon a weighted axis that rights its direction after the robot flips

MMW Radiometers

Electronics-cont’d

• Built in GPS: – built into the robot for a sense of control– allows robot to record its movements– Allows for a human controller to tell the robot

what areas to cover• All collected data will be stored in a hard

drive• The laptop will download and analyze the

information• Modular design for easy maintenance

Manufacturing

• Easy to make in most factory/lab settings

• Outsourced parts will be put together under a short term contract

• Will need a long term contract for replacement parts

Maintenance

• Tires are easy to replace

• Standard parts available from many manufactures

• Simple to maintain/fix on site once parts arrive

• Electric system is modular and can be easily maintained

Cost

• Initial Building costs– 16 foot extrusion of aluminum: $50– 12 (5/8” ball bearings) times $23.77 = $285.24– Nylon chain: $102– Sprockets: $86– Lexan: $10– 5/8 keyed shaft: $35– 3 foot angled aluminum: $20– Rectangular support bar: $23– 24” keyed stock: $3– Motors, gearboxes, and wheels from Kit of Parts– Total: $600 to $650 (without electronics)

Costs-cont’d

• Maintenance costs– Due to replacement parts

• Because replacement parts are standardized, costs should be high

• Analysis of funds available– Costs can be lowered by changing sensor

type to metal detector

Weight

• Total Weight– 22 pounds without electric parts– Light enough not to set off the mines

Comparison to Army

• Unofficial Army motto: Bigger is better.– Prototype robot to sense landmines weighed

more than 200 lbs– Accuracy was questionable

• WBI 461 Deminer: Simple is success.– Light, maneuverable, versatile– New sensor technologies have lower price

and better accuracy

Drawbacks

• Moisture may be a problem• Clearance is low• Laptop may not be widely available in foreign

nations• The small market may incur high manufacturing

costs• Large tires are needed to ensure stability• There may not be enough power to flip robot

over• However, most issues would be caused by

problems with the sensor

Future Improvements

• Lighter plastic-based frame

• Better sensor technology

• Better strategy to deal with large obstacles

• Wider wheels

• Easier usability such that private persons can map their own land

WBI 461 Commitment

• West Side Boilerinvasion Team #461, WBI 461, is committed to helping its community and the populace at large

• WBI 461 is aware of the great problems landmines are today

• The preceding presentation was WBI 461’s attempt at relieving the problems due to landmines

Top View Front View

Left View Perspective View

Ball Bearing and Wheel

AdapterPerspective View

AdapterPerspective View

MMW Radiometers

• “Soil and metal respond very differently to the high frequency of millimeter waves. Soil has a high emissivity and low reflectivity . . . metal has a low emissivity and strong reflectivityle. Using a millimeter wave radiometer, in the frequency range of 30 to 300 GHz, this contrast could be measured. Studies have been conducted on plastic mines as well, which have lower reflectivity. The detector had to use lower frequencies; however, it was successful. MMW radiometers are simpler devices than GPR [and] they should suffer less from clutter problems.”

http://maic.jmu.edu/dtif/Conferences/Monterey/Macpherson.pdf