1. BSAC ©2003 Fall IAB. Confidential Information. Not to be made public without permission from UC Regents. Localization for Off-the-Shelf Distributed Robots (CotsBots) Sarah Bergbreiter Kris Pister September 9, 2003

2. BSAC ©2003 Fall IAB. Confidential Information. Not to be made public without permission from UC Regents. History of CotsBots – Building More of Less Solar Cell Array CCRs XL CMOS IC

3. BSAC ©2003 Fall IAB. Confidential Information. Not to be made public without permission from UC Regents. Similar Robot Platforms Khepera II –> $2500 each Robomote (USC) –custom hardware Millibots (CMU) –custom hardware CotsBots (UCB) –standard hardware and software platform –~$200

4. BSAC ©2003 Fall IAB. Confidential Information. Not to be made public without permission from UC Regents. CotsBots: Hardware Atmel ATMEGA103 –4 Mhz 8-bit CPU –4KB RAM –128KB Program Memory RFM TR1000 radio –50 kb/s – ASK –Focused hardware acceleration Network programming Atmel ATmega8L –1-8MHz CPU –8KB Program Memory –1KB RAM 2 Discrete H-Bridge Circuits –Speed and Direction Control of Motors –up to 4A, 30V load Same 51-pin bus Mica Mote MotorBoard Kyosho Mini-Z RC Car Platform Additional sensor boards available including ADXL202e, magnetometer, light, temp, sound, etc.

5. BSAC ©2003 Fall IAB. Confidential Information. Not to be made public without permission from UC Regents. CotsBots: Software Use Open-Source NesC language and code provided by TinyOS group (available on SourceForge) Abstract as much as possible from the application writer (developer should focus on algorithms) Remain flexible by keeping component-based design Robot Application ClockRobot Motor Packet Motor Software Motor Packet MZ, Tank,... Motor1MZServo ADC

6. BSAC ©2003 Fall IAB. Confidential Information. Not to be made public without permission from UC Regents. CotsBots Sample Application: Robot Diffusion T -------- z - 1 K T -------- z - 1 K 30... ROBOT MOTOR + _ + _ + DISTANCE/ LOCATION SENSOR _ FEEDBACK AND CONTROL LOOP Conceptual Vision of Robot Diffusion – could be used for mapping or maximal sensor network coverage Controller designed for diffusion along 1DOF – only tested in simulation thus far

7. BSAC ©2003 Fall IAB. Confidential Information. Not to be made public without permission from UC Regents. Fisheye Lens High Power LED PhotoBeacon IC Localization: PhotoBeacon Concept Triangulation v. Trilateration Use light/lens/detector system on each robot to determine relative angles Design an IC with ~1 o resolution and 5-10m ranges with conventional off- the-shelf LEDs IC should be computationally simple Additional benefits of optical communication and obstacle detection    d

8. BSAC ©2003 Fall IAB. Confidential Information. Not to be made public without permission from UC Regents. PhotoBeacon: System Architecture 256x1 Analog Mux....... Programmable Gain Amplifier (KSJP20) Photodiodes in circular array 3-wire bus Differential Analog Output 190 o field-of- view lens 5o5o Lens LED Low divergence, high power LEDs PhotoBeacon IC (detector)

9. BSAC ©2003 Fall IAB. Confidential Information. Not to be made public without permission from UC Regents. PhotoBeacon IC: Final Layout PhotoDiodes 3-wire bus block 1Mbps Optical Receiver ~4mm

10. BSAC ©2003 Fall IAB. Confidential Information. Not to be made public without permission from UC Regents. PhotoBeacon IC: Preliminary Results Tested ¼ ring PhotoBeacon IC All blocks are functional, including optical receiver, multiplexer, and 3-wire bus 3-D manipulator used to position fisheye lens over IC Difficulty in focusing results in an intensity graph instead of binary output Laser Lens+IC LabView DAQ Box

11. BSAC ©2003 Fall IAB. Confidential Information. Not to be made public without permission from UC Regents. Conclusions and Future Work Continue testing PhotoBeacon localization system Apply lessons learned to new PhotoBeacon IC utilizing latest optical receiver from Brian Liebowitz and the SALT project in KSJP20 Investigate algorithms for PhotoBeacon system based on Lance Doherty’s work in Convex Position Estimation in Wireless Sensor Networks. Infocom 2001 Integrate PhotoBeacon system with CotsBots’ hardware and software