中文摘要：

通过对电动助力转向系统的研究，分别建立了折线型助力特性曲线、动力学仿真模型、包含基本助力、PID、PWM组成的EPS控制器模型，仿真分析了目标电流的跟踪特性、验证分析了助力特性，分析了EPS系统的转向轻便性和路感特性。仿真表明，实际电流对目标电流跟踪效果较好，转向轻便性得到改善，车速提高后，驾驶员获得了较强的路感，车速越高助力电动机提供的助力转矩越小，控制策略合理有效。

英文摘要：

In this paper,the assist characteristic curve with fold linear control for EPS were built,the EPS dynamicmathematical models were established.On the basis of the analysis of the mathematical model for each departments,thewhole simulation model were constructed,The EPS control model including the assist characteristic curve、PID and PWMcontrol method.The tracking performance characteristics of the actual current to the target current,verifying and analyzingthe assist characteristic and the steering portability and road feeling characteristics for EPS were accomplished and analyzedby simulation.The results show that the tracking performance is effective.The steering portability was enhancedcorrespondingly with EPS,the driver has a stronger road feeling with the speed increasing.Under the same steering wheelpower,the higher the vehicle speed,the lower torque of the power assisted motor was.In short,it was proved that thecontrol strategies is effective.