汽车EPS动力学模型分析及控制系统设计

ANALYSIS OF DYNAMIC MODEL OF ELECTRIC POWER STEERING SYSTEM OF AUTOMOBILE AND THE DESIGN OF ITS CONTROL SYSTEM

与传统的转向系统相比较,汽车电动助力转向系统(EPS)结构简单,灵活性好,能充分满足汽车转向性能的要求,在操作的舒适性、安全性和节能、环保等方面显示出显著的优越性。介绍了汽车电动助力转向系统的结构和工作原理,以方向盘转角为输入、输入轴扭矩为输出,推导出系统的传递函数和频率特性,定量地分析了参数对转向轻便性、稳态误差和跟踪性的影响。结果显示,在一定范围内选择不同的比例增益、积分增益和微分增益,可以使幅频特性和相频特性发生变化,达到优化转向系统的助力作用、控制助力稳态误差和提高响应的灵敏度的目的。同时给出了系统的控制电路图。

Comparing with traditional steering system the electric power steering (EPS) system of the automobiles is simpler in structure, more flexible; and can fully meet the requirements of steering performances. EPS also has prominent advantages in the comfortableness and security of steering, energy saving, and environmental protection. An introduction of the structure of EPS and its working principle were described in this paper. The transfer function and frequency characteristic of the system, in which the steering angle was regarded as the input and the torque of steering axle was regarded as the output, was established, and the influence of all the parameters of the system on the handiness, steady state error and track of the steering system was discussed. The results showed that in order to optimize the effects of steering performances, control the steady error, and improve the sensitivity of the response, characteristic of amplitudefrequency and phasefrequency should be altered by choosing different proportion gain, integral gain, and differential gain. The detailed hardware control design was also given.