基于Matlab的EPS系统转向特性研究及仿真分析

Study and Simulation Analysis on Steering Characteristics of EPS System Based on Matlab

汽车的转向操控特性主要取决于电动助力转向(EPS)系统的机械结构特性和电气控制特性,从EPS系统的机械结构方面来看,提升其转向特性的空间不大,但EPS系统的控制策略和电气控制方面还是有很大的提升空间。基于EPS系统的工作原理,分析了其力矩传递函数,结合EPS系统转向的动态特性要求,建立了EPS电机的电流控制方程。在Matlab中建立了相应的动态仿真模型,并对EPS系统的转向特性进行了仿真分析。研究了K_P、K_i、K_d参数对EPS系统转向特性响应输出的影响规律,为EPS系统的控制优化提供了技术支持。

The steering characteristics of a vehicle are mainly depending upon the mechanical and electrical control properties of EPS system, however,its steering characteristics could be hardly improved from view of mechanical structure of EPS system, but it is possible to be improved from its control strategy and electrical structure property. Based on the principle of EPS, the transfer function of torque of EPS is analyzed, and current control function of EPS motor is established combining with requirement of dynamic characteristic of EPS system. The dynamic simulation model is also set up in the Matlab, and the steering characteristics of EPS system is analyzed and discussed. The effect of parameter Kp, Ki, Kd of PID controller on steering characteristics output of EPS is studied. The simulation results can be used for optimization in EPS design.