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Personal Rapid Transit Scale Model. Advanced Transit Association Annual Technical Meeting January 21, 2012 College Park, Maryland Robert Johnson R. E. Johnson Consulting Rockville, Maryland www.REJConsult.com. Model of PRT Vehicle that Steers Itself on a Flat Surface. ULTra
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Personal Rapid Transit Scale Model Advanced Transit Association Annual Technical Meeting January 21, 2012 College Park, Maryland Robert Johnson R. E. Johnson ConsultingRockville, Marylandwww.REJConsult.com
Model of PRT Vehicle that Steers Itself on a Flat Surface • ULTra • 2getthere Masdar Vehicle www.REJConsult.com
Why Use Scale Model to Develop Control Software? • More realistic than pure simulation • Avoids assumptions that are not physically possible • Can demonstrate system operation • Suitable for computer vision based control, which is independent of scale • Modern electronics are small enough to fit inside scale model www.REJConsult.com
Model Uses Distributed Control System • Fully autonomous vehicles • Three computer systems • Central control • On-board computer vision system • On-board microcontroller www.REJConsult.com
Central Control • Like taxi dispatcher, not safety related • Radio link to vehicles • Handles empty vehicle routing • Supports operator monitoring of system and operator intervention if necessary • Could be Windows or Linux PC • Scale Model uses C# program on Windows PC www.REJConsult.com
On-board Computer Vision System • Detects vehicles ahead in same lane • Detects vehicles at merges and in stations • Detects trespassers / foreign objects on roadway • Could provide lateral guidance • “Soft” real time system • Probably would use Linux as operating system www.REJConsult.com
On-board Microcontroller • Operates steering, drive motor, brakes, doors, etc. • Monitors computer vision system • Microcontroller is a vital system • Scale model uses 32-bit ARM Cortex M made by NXP Semiconductors www.REJConsult.com
Updates Since Last Year’s Technix • Changed scale from 1/9 to 1/12 • Currently have two operating vehicles • Vehicles can drive themselves around test loop www.REJConsult.com
Change to 1/12 Scale • Vehicle is 12.5 inches (32 cm) long • Can still hold new, smaller computer-vision processors that have recently become available • More convenient size, especially test track www.REJConsult.com
Last Year -- 1/9 Scale Vehicle www.REJConsult.com
1/12 Scale Vehicle -- Right Side www.REJConsult.com
1/12 Scale VehicleElevated View of Front www.REJConsult.com
1/12 Scale Vehicle – Left Side www.REJConsult.com
1/12 Scale Vehicle -- Left Front www.REJConsult.com
1/12 Scale Vehicle on Half Loop www.REJConsult.com
Future Work • Refine and complete existing vehicles • Computer vision • Vehicle following • Merging • Station operations www.REJConsult.com