AP Auto-Parking (Autonomous Parallel Parking Car) Prepared by: Abdullah F. F. Shehadeh Abd-Errazzaq Shehadeh Hardware Graduation Project 2010 - 2011
AP • Parallel parking is one of the most complex driving scenarios. AP is system that enables cars to parallel park autonomously. • The car starts by measuring the slots between parked cars until it finds a slot that fits it. The minimum slot required for the car to park in is twice the car length. • If the slot is insufficient, the car continue searching for a suitable one. • Once the car finds a suitable slot it enters the parallel parking mode. By the end of this mode, the car will be parked.
Devices Used: • PIC 18F4550: USB Microcontroller. • SHARP IR sensors (GP2Y0A21YK): three sensors (10-80cm). • H-Bridge (L298N). • 5-V, 9-V voltage regulators (7805, 7809). • Car model. • Two 3.7 rechargeable batteries. • PC power supply. • PCB: Printed Circuit Board.
Distance Sensors Types: • Ultrasonic Sensors: we avoid their usage because of the nature of ultrasonic waves (not directed) that causes many reflections. • IR Sensors: we chose this type because of its simplicity and it covers the ranges we need. We used three (10 – 80 cm) sensors. A longer range exists (up to 1.5 m) can be used when applying the system to real cases.
Sensors Direction • It is preferred to position the sensor such that it is orthogonal with respect to the motion direction.
Mathematical Model • We have derived an equation that describes the car motion in auto-parking mode:
Mathematical Model According to sine rule:
Mathematical Model By substituting (1) in (2): The last equation describes the motion of the car.
Mathematical Model • By substituting the values of r and s: Using MS Excel, we have solved this equation for many values:
Problems we faced! • PCB: It is our first project using printed circuits. We have learned how to work on Eagle program and we have faced many problems making the appropriate routing. • PIC 18F4550: It is a USB microcontroller that requires the use of special bootloaders and programs like MPLAB. We faced many problems in defining it on Windows 7.
Problems we faced! • Mechanical problems: we changed the car model twice, in order to use a small car that can be driven using batteries, but finally we were obliged to use power supply in order to supply the motors with the required current. Another mechanical problem is the rotation angle of the front motor which is much smaller than the real case, what results in the need of doing the parking on many stages.
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