Research And Development Of The Control System Of The Bus Door Swung Outside

To improve the performance of the bus door swung outside, the new type of control system which include permanent magnet brushless DC motor (BLDCM) and AT89C52 MCU composing a high performance servo system was developed. The hardware design and control software programming and system simulation are finished in this system.The microcontroller unit AT89C52 of ATMEL Corporation and the Application Specific Integrated Circuit (ASIC) MC33035 and MC33039 of MOTOROLA Corporation are used as the main controller in the hardware system. On the basis of the function analysis of AT89C52 and MC33035 and MC33039, the power circuit, the control circuit, the drive on-off circuit and the overcurrent and protection circuit are also given. The anti-disturbance steps are used in the design of hardware circuit, which makes the system work safe and reliable.The modularized design is used in the software system. The design of main program module, the basic program module and the function program module are introduced. First, the function of system is initialization in the main program. Second, the running parameters and the interrupt control are presented in the basic program module. Finally, the starting of motor and forward and reverse of motor are realized, and the speed of motor is adjusted by changing the duty cycle of PWM signals using PID method, this makes system possess high adjustable speed precision in the function program.In the end of dissertation, the classical digital PID control arithmetic are used, and the digital circuit loop and the digital velocity loop are also designed, then the simulation of the motor control system is done with SIMULINK of MATLAB software. The double closed loops are proved to be right and the reliability of the system is good.