Personal Rapid Transit Scale Model

Control System for Scale Model PRT VehicleAdvanced Transit Association Annual Technical MeetingJanuary 13, 2013College Park, Maryland

Robert Johnson

R. E. Johnson ConsultingRockville, Marylandwww.REJConsult.com1Model of PRT Vehicle that Steers Itself on a Flat SurfaceUltra

2getthere Masdar Vehiclewww.REJConsult.com2

Why Use Scale Model to Develop Control Software?More realistic than pure simulationAvoids assumptions that are not physically possibleCan demonstrate system operationSuitable for computer vision based control, which is independent of scaleModern electronics are small enough to fit inside 1/12th scale model 12.5 in (32 cm) longwww.REJConsult.com3PRT Scale Model Right Sidewww.REJConsult.com4

PRT Scale Model Showing Lateral Sensor Ahead of Front Wheelwww.REJConsult.com5

External Appearancewww.REJConsult.com6

Autonomous Vehicle with Three Levels of Computer Control Central control (like taxi dispatcher, not safety related)On-board computer vision system running Linux -- provides longitudinal controlOn-board microcontroller (only vital system)Monitors vision computer Provides lateral control by using sensor to measure distance to sidewallControls steering, drive motor, brakes, etc.www.REJConsult.com7Lateral Control Demonstrationwww.REJConsult.com8

Updates Since Last Years TechnixFinalized vehicle design except vision systemElectro/mechanical aspects of vision system complete (power supply, etc.)Achieved basic vehicle following using netbook as vision computer

www.REJConsult.com9Small, Inexpensive, Low-Power ARM Computers for Vision Processingwww.REJConsult.com10

Small Multi-Core ARM Computers for Less Than $200 with Linux SupportPandaboard Texas Instruments4.5x4.0 (114x102 mm)

i.MX6 Q Sabre LiteFreescale Semiconductor3.3x3.3 (83x83 mm)www.REJConsult.com11

Current Status of Vision-Based Longitudinal ControlOpenCV vision software operational on x86 PC running Ubuntu LinuxWebcam support not an issue for x86 UbuntuBasic vehicle following using color tracking of target on rear of lead vehicleAs temporary measure, communicate with microcontroller by changing brightness of portion of PC displaywww.REJConsult.com12Vehicle Followingwww.REJConsult.com13

Future Work Requires Mostly OpenCV and Linux SkillsPort existing software to small ARM computerEstablish suitable communications link between vision computer and microcontrollerMergingStation operationswww.REJConsult.com14