Study Of Column Electric Power Steering Based On Current Tracking Control

Electric Power Steering is the fourth generation in intelligent automobile power steering system domain after the Electric Hydraulic Power Steering. It could dynamic adjust the motor working status that used output a appropriate steering torque through inducing driver steering torque and vehicle speed in real-time. Electric Power Steering is in line with the modern cars for the low-carbon, environment protection, safety requirements, and reflects the module, intelligent, simple design concept of the future automobile, it owns a huge market prospects.In this paper, we select the Column- Electric Power Steering(C-EPS) as the research object. For the problem that the assist motor between actual output torque and the target output existed deviation, the fuzzy PID control strategy is adopted to control the actual current of the motor tracking precisely the target current. Compared to the conventional PID control strategy, it got a good tracking result.Through analyzing the structure and mechanics of the C-EPS system, and combining the vehicle dynamic characteristics, we established a two degrees freedom simplified C-EPS model which included driver model, torque sensor model, electronic control unit model and mechanical steering system model. On the basis of fuzzy PID control strategy for the motor current tracking, the simulation analyzed the steering lightly and the"road feel"aspects which are owned C-EPS important system performance. Furthermore, the current damping compensated control in motor current to suppressing road surface disturbance to the steering wheel is adopted.To making C-EPS system simulation model has an intuitionistic display, we also through using MATLAB graphical user interface toolbox, and with the C-EPS system SIMULINK model, compiling a simple simulation system. In the human-computer interactive simulation aspect we have made some attempts.Finally, to achieving C-EPS system hardware test environment, we designed electronic control unit module. TMS320F2812 DSP with high-performance chip as the main control system, AD sampling part of the system and test bench serial communication module had a detailed designed.