Dsp-based Small Electric Steering Gear Servo Control System

The electric actuator system is a complex electro-mechanical system, at the same time also is a kind of high precision position servo system.It has important influence to body's attitude control. In order to improve the control performance of electric actuator system, on the basis of the characteristics of the electric actuator system, this paper designed a control system by brushless dc motor, and the system control strategy is researched.This paper introduces the structure composition and working principle of the brushless dc motor,and established mathematical model of brushless dc motor.According to the electric actuator system's control process, all parts of the system's simulation models are created through the MATLAB/SIMULINK window,lay the foundation of the system simulation under different controllers.The electric actuator controll system adopts the three-loop control strategy generallly,on currently foundation of keep speed loop and current loop control algorithm invariably, this paper designed the position loop control algorithm:PID controll and fuzzy-PID control.The system's response and tracking performance under different controllers are analysised through the simulation.On the basis of theoretical analysis, this paper takes the TI company Digital Signal Processor (DSP)-TMS320F2812 as the core control chip,and hardware parts and software parts are designed combine CAN bus.The hardware parts includes communication interface circuit design,MOSFET driving circuit design,optoelectric isolation circuit design. The software includes the main program design, initialization subprogram design, the position loop algorithm design and communication interface window design,etc.Finally, the system hardware and software are debug, and response performance experiment and tracking performance experiment are conducted. The simulation and experimental results show that, PID control and fuzzy PID control can be applied to the electric control system, all can achieved the desired objectives,but the fuzzy PID controller's control effect is better than traditional PID controller.