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Automatic Valet Parking

Automatic Valet Parking

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Automatic Valet Parking

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  1. Automatic Valet Parking Senior Design Project Spring 2009 MajidHasan Andrew Muehlfeld David Sheridan

  2. Outline • Introduction • Design & Test • Keychain • GPS Chips • Wireless System • Car • Sensors • Navigation • MSP430 • Car Control • Conclusion

  3. Outline • Introduction • Design & Test • Keychain • GPS Chips • Wireless System • Car • Sensors • Navigation • MSP430 • Car Control • Conclusion

  4. Introduction • Automatic Valet Parking • “Unparking” • Car & Keychain

  5. Outline • Introduction • Design & Test • Keychain • GPS Chips • Wireless System • Car • Sensors • Navigation • MSP430 • Car Control • Conclusion

  6. Design – High Level Diagram

  7. Outline • Introduction • Design & Test • Keychain • GPS Chips • Wireless System • Car • Sensors • Navigation • MSP430 • Car Control • Conclusion

  8. Design - Keychain

  9. Design - Keychain

  10. Outline • Introduction • Design & Test • Keychain • GPS Chips • Wireless System • Car • Sensors • Navigation • MSP430 • Car Control • Conclusion

  11. GPS Chips • Garmin 15H • RS232 Interface – to MAX 232 • MAX 232 to Wireless Transmitter • Same message from Keychain and Car • Parsed in microcontroller on Car • Checksum computation & comparison

  12. GPS Testing Distance Between Final Resting Place and Target Distance Between Two Chips at Same Point

  13. GPS Challenges & Successes • Only works outside • Only updates once per second • RS232 – T.T.L. Conversion • Slow fix • Programming • Preferred Message • Slower Bit Rate

  14. GPS - Recommendations • Use SiRF Chips • Faster update rate • Faster initial fix • Use 3.3V Chip

  15. Outline • Introduction • Design & Test • Keychain • GPS Chips • Wireless System • Car • Sensors • Navigation • MSP430 • Car Control • Conclusion

  16. Wireless System • Linx Chips • Linx HP Series • Linx LR Series • Linx LT Series

  17. Wireless System - Testing • Distance Testing • Max Distance: 18m • Min Time: 4s • Spectrum Analyzer • Oscilloscope

  18. Wireless System - Challenges • Three CompEs learning to use antennas • Linx High Performance • 900 MHz • Max Range: 5m • Linx Long Range • 418 MHz • Max Range: 18m • Thanks James Doran

  19. Wireless System - Challenges • Impedance Matching Antennas • Broken Chip • Replaced with LT (Transceiver) • Thanks Again James Doran • Ground Plane Design • Thanks Professor Makela • Bit Errors • Reduce Data Rate on GPS Chip

  20. Wireless System - Recommendations • Use Linx Long Range series

  21. Outline • Introduction • Design & Test • Keychain • GPS Chips • Wireless System • Car • Sensors • Navigation • MSP430 • Car Control • Conclusion

  22. Design - Car

  23. Design - Car

  24. Outline • Introduction • Design & Test • Keychain • GPS Chips • Wireless System • Car • Sensors • Navigation • MSP430 • Car Control • Conclusion

  25. Sensors • Implementation • Testing • Challenges & Successes • Recommendations

  26. Sensors – Implementation • Three sensors mounted on front • Sensor-based navigation may override GPS-based navigation • Analog voltages go to ADC on MSP430 • Sampled ten times per second

  27. Sensors – Testing • Policy tested through debugger with motor disconnected • Integration tested through actual field test and debug LEDs • Determined actual range of sensors compared with theoretical range

  28. Sensors – Testing

  29. Sensors – Challenges • Optimizing false alarms vs. false misses • Proper sensor placement Image from maxbotix.com

  30. Sensors – Recommendations • Three rear sensors for rear obstacle detection • Permits safe reversing

  31. Outline • Introduction • Design & Test • Keychain • GPS Chips • Wireless System • Car • Sensors • Navigation • MSP430 • Car Control • Conclusion

  32. Navigation • Implementation • Testing • Challenges & Successes • Recommendations

  33. Navigation - Implementation • The car moves according to GPS information unless it finds an obstacle • The car stops moving within five meters of its target • Proportional control is used to steer car toward its heading

  34. Navigation - Implementation

  35. Navigation – Testing • GPS Navigation • Proportional control (originally PID) needed tuning to avoid instability and reduce oscillation via field testing • Sensor Navigation • Made sure car returned to GPS navigation when sensors not obstructed

  36. Navigation – Challenges • Avoiding proportional control instability • Eliminating initial condition instability • Minimizing proportional control oscillations

  37. Navigation – Recommendations • Add derivative control • Needs to be suspended occasionally to avoid instability • Decrease stopping range • Optimal distance could be further tuned

  38. Outline • Introduction • Design & Test • Keychain • GPS Chips • Wireless System • Car • Sensors • Navigation • MSP430 • Car Control • Conclusion

  39. Microcontroller

  40. Microcontroller – Implementation • The “brain” of the car • Reads GPS coordinates and sensor data • Determines the speed and direction • Features • USART serial communication • Analog-Digital Converter • Pulse Width Modulation

  41. Microcontroller - Testing • Simulations • Model realistic behavior • Determine if input corresponds to appropriate output • JTAG Debug Interface • Allows realtime debugging • LED Array • Easily monitor current state of MCU

  42. Microcontroller - Challenges • Obtaining hardware • Debug board required, expensive • Code size limit • Software quickly exceeded trial limitation • Obtained non-limited software from TI • Interfacing with devices • Configuration can be tedious • TI provides user guide and code examples

  43. Microcontroller - Recommendations • Would use this type of MCU again • Feature-rich • Fast • Relatively easy to use • Good documentation

  44. Outline • Introduction • Design & Test • Keychain • GPS Chips • Wireless System • Car • Sensors • Navigation • MSP430 • Car Control • Conclusion

  45. Car Control - Implementation • Steering Servo • Sets car direction based on pulses from MCU • Pulse width determines degree of turn • Electronic Speed Control • Controls motor speed by setting duty cycle • Amplifies voltage from MSP signal

  46. Car Control

  47. Car Control - Testing • Steering Servo • Wrote MCU software to test range of motion • Checked that wheels fully turn • Electronic Speed Control • Wrote software to test range of duty cycle • Monitored behavior on oscilloscope

  48. Car Control - Challenges • Steering Servo • Original servo on car did not work • Replaced servo, worked perfectly • Electronic Speed Control • Original Speed control also did not work • Purchased RC car ESC, impossible to program • Replaced with simple motor control circuit

  49. Car Control - Recommendations • Steering Servo • This unit works perfectly • Electronic Speed Control • Modify unit specifically for RC car control • Car speed is sporadic • Due to uneven surface, draining battery • Monitor current speed and adjust duty cycle

  50. Outline • Introduction • Design & Test • Keychain • GPS Chips • Wireless System • Car • Sensors • Navigation • MSP430 • Car Control • Conclusion