汽车电动助力转向系统回正特性控制逻辑分析

Analysis of Control Logic for Return-to-center Performance Of an Electric Power Steering System

以汽车转向系转向特性为研究对象和目标,为了探讨汽车转向回正特性对汽车行驶安全和操纵稳定性的影响,降低驾驶员施加于方向盘的转向力矩,并使驾驶员获得良好的路感,改善汽车转向系的回正特性,提出了一种电动助力转向系统回正控制算法以提高转向盘的回正特性,开发了一种基于转向盘转角估计的PID控制策略.为了分析获得汽车转向回正特性和回正控制逻辑,通过分析和物理模型简化建立了电动助力转向系统的动力学模型,并根据建立的模型,对提出的控制策略进行了仿真分析,结果表明此控制策略可提高转向盘的回正特性和稳定性,利于提高汽车行驶的安全性和操纵稳定性.

Based on some analyses o[ the structure and opcrating principle of an electric power steering system （EPS）, this paper conducts a strategic study of the dynamic model of EPS and its control logic for reduction in steering torque and for return-to-center performance. In order to prove that this EPS improves steering characteristics and realizes good steering feelings, the paper also develops a simulation system that can implement an actual load torque delivered to the steering column. With the proposed EPS logic, the driver can turn the steering wheel with a torque whose magnitude is determined from a torque map independent of load torques Ihat tend to vary with the driving conditions. Results from simulation and experiments show that the proposed control schemes can reduce the steering torque and improve the return-to-center performance.