Curtis Gittens Daniel Goundar Daniel Law Johannes Minor

Curtis Gittens Daniel Goundar Daniel Law Johannes Minor April 14 th 2008

The Team l Curtis Gittens ¡ ¡ l Dan Law ¡ ¡ l Electronics Parts Selection & Purchasing Johannes Minor ¡ ¡ l Electronics Microcontroller Programming Solid. Works Controller Design Daniel Goundar ¡ ¡ Solid. Works Adhesives & Passive Pre-loading

Outline Motivation l System Overview l Design & Implementation l ¡ ¡ ¡ Structural/Mechanical Design Electronics Subsystem Control System Timeline and Finances l Future Development l ¡ Market Outlook/Research Opportunities What we have learnt as a Team l Conclusion l ¡ ¡ Acknowledgements Questions

Motivation l Useful in hostile & inaccessible environments l Can substitute robots where human safety would be at risk l Diverse applications (inspections, research, maintenance) l Large increase in research into highly mobile robots, capable of navigating both natural and artificial terrain l Rapidly growing field of research, little product development

Solution l Small robots that can navigate man made environments, without being impeded by walls and corners l Light-weight, durable, and autonomous l Wall scaling using passive adhesives l Mobility in two dimensions on horizontal and vertical surfaces l Inexpensive commercial wall-climbers

System Overview l Functional Requirement Summary ¡ ¡ Diverse mobility Scalability

Design & Implementation: Module Design Iterations First Iteration: • • • Drive Belt System Motor Mounted in Center Optical Encoder shaft passes through axle Spring loaded front axle Spindly chassis supports Weight: 45 g Second Iteration: • • • Motor attached directly to wheel More integrated optical encoder Improved strength in spring axle More robust chassis Reduced wheel-channel depth Weight: 41 g Final Iteration: • • Light-weight dual potentiometer design Identical front end Substantial weight savings Weight: 31 g

Design & Implementation: Single Module Design

Design & Implementation: Single Module Design GM 14 a Gear Motor Track Belt Drive Wheel Two rotary Potentiometers, 180 degrees out of phase Spring-loaded front axle to keep track belt in tension

Design & Implementation: Inter-Module Connections

Design & Implementation: Tail Design

Design & Implementation: Adhesive Selection l Used a variety of household adhesives l Varying results (scotch & carpet tape, foam, rubber cement) l Issues with adhesive separating from belts l Carpet tape was the final choice of adhesive

Design & Implementation: Electronic

Design & Implementation: Electronic

Design & Implementation: Electronic Component Selection l Microcontroller- TI MSP 430 F 169 ¡ ¡ ¡ l Analog Multiplexers - DG 408 ¡ l Just your standard 8 x 1 Analog Mux H-bridges - L 293 D ¡ l Hardware timers for motor drive and input sampling 12 bit ADC Hardware multiplier Quad Channel Push button remote

Design & Implementation: Software l Interrupt driven l Scalable l Digital filtering of potentiometer feedback l Fixed point signal processing

Design & Implementation: Single Module Speed Control

Design & Implementation: Smooth Turning Algorithm

Design & Implementation: Smooth Turning Algorithm

Timeline

Budget Description Budg et e d C o st Total Cost C fo o r st 6 M o d ul es Power Supply $30. 0 $0. 75 $0. 00 0 Microcontroller $60. 0 0 Misc. Electronic Components $20. 0 $85. 0 $45. 0 0 Motors and Actuators $300. 00 $263. 60 $123. 96 Rapid Prototyping $300. 00 $315. 75 $106. 75 $151. $47. 0 50 0

Funding Description Budgeted Amount Engineering Science Student Endowment Fund Actual Amount $250. 00 $470. 00 $50. 00 $40. 00 Group Funding $225. 00 $106. 43 Sponsorship from Dr. Carlo Menon $300. 00 $415. 97 $825. 00 $1, 032. 40 Departmental Funding Total

Market Outlook/ Research Opportunities l Nuclear power plant inspection l Space research l Maintenance on tall structures

Future Development l Autonomous control l Active pre-loading l Advanced Adhesives

What We Have Learnt l Difficult to design in parallel when electronics and mechanical designs require integration from the start l Signal noise manages to creep into most everything l Shipping inflates total cost of components l Budgeting for time improves with experience l Debugging and tweaking takes bulk of development time

Acknowledgements l Dr. Carlo Menon ¡ l Gary Houghton ¡ l Input and feedback on design choices Rapid prototyping of plastics ESSEF Endowment Fund ¡ Funding ($470. 00)

Questions l Videos and Demonstration

Appendix Performance Summary l Technical Information: Results l Financial Details l

Performance Summary Performance Prototype Specifications Measured MTTF 2 minutes > 5 minutes Max Speed 1 cm/s Turning Radius 75 cm 5. 7 cm/s 75 cm 90° transition 2 x 2 3 x 2

Technical Information: Results

Technical Information: Results

Technical Information: Results

Description Quantity Unit Price Power Supply Cost $0. 75 discarded batteries 10 $0. 00 battery clip (2 x AA) 1 $0. 75 Microcontroller $151. 50 MSP 430 F 169 3 $30. 00 $90. 00 Multiplexers 2 $2. 50 $5. 00 H-Bridges 3 $4. 50 $13. 50 Programming Cable 1 $25. 00 Voltage Regulator 6 $3. 00 $18. 00 Misc. Electronic Components $85. 00 Parts from Fred $35. 00 Headers/Sockets $50. 00 Motors and Actuators $263. 60 GM 12 a 1 $15. 00 GM 14 a 9 $15. 00 $135. 00 Belts, pulley, U-joint Springs 34 $100. 00 $0. 40 $13. 60

Description Rapid Prototyping Quantity Unit Price $315. 75 $300. 00 Aluminum Bars Adhesive Various tapes and glues Sensors 7 $15. 75 $30. 00 $135. 80 30 $55. 80 $20. 00 $60. 00 10 Contact Encoders $1. 86 3 Optical Encoders Contingency $2. 25 Rotary Potentiometers Light/IR sensor Cost $0. 50 $5. 00 $15. 00 $50. 00 Total $1, 032. 40

Cost for 6 Modules Description Power Supply Quantity Unit Price discarded batteries Microcontroller 10 MSP 430 F 169 $0. 00 $47. 00 $30. 00 $2. 50 $5. 00 2 $4. 50 $9. 00 1 Voltage Regulator Headers/Sockets $0. 00 2 H-Bridges Parts from Fred $0. 00 1 Multiplexers Misc. Electronic Components Cost $3. 00 $45. 00 $35. 00 $10. 00

Description Motors and Actuators Quantity Unit Price GM 14 a Rotary Potentiometers $6. 00 $30. 00 $0. 33 $3. 96 $106. 75 $100. 00 3 Carpet Tape Sensors $90. 00 12 Aluminum Bars Adhesive $15. 00 5 Springs Rapid Prototyping $123. 96 6 Belts Rapid Prototyping Cost $2. 25 1 $5. 00 12 $6. 75 $5. 00 $22. 32 $1. 86 $22. 32 Total $350. 03

Sample Second Order Filter Output