基于电动伺服系统的转向试验台阻力加载策略的研究

A Research on the Resistance Loading Strategy for Steering Test Bench Based on Motor Servo System

以电动伺服缸为核心的转向台架加载系统在加载过程中受减速丝杠内部摩擦、阻尼和惯量等非线性因素影响,电机电磁转矩与缸体端部实际加载阻力并非简单的减速比关系,同时被测转向系统的位移扰动产生的多余力也对阻力加载精度产生较大影响。针对这些问题,本文中首先建立转向台架的传递函数,采用PID力闭环控制和串联校正方法来提高阻力加载系统的稳定裕度和加载精度,在此基础上利用结构不变性原理和速度补偿控制对多余力进行抑制。仿真和台架试验结果表明,提出的阻力加载控制策略可有效提高加载精度和减小扰动下多余力的影响。

In the loading system of steering test bench with motor servo cylinder as its core,it is not really a simple relationship of reduction gear ratio between the electro-magnetic torque of motor and the resistance actually loaded at cylinder end due to the effects of some nonlinear factors such as friction,damping and inertia in ball-screw pair during loading. In addition,the redundant force generated by the displacement disturbance of tested steering system also has rather significant effects on resistance loading accuracy. In view of these problems,firstly the transfer functions of steering test bench are built,and PID force closed-loop control and series correction are adopted to enhance the stability margin and loading accuracy of resistance loading system. Then on this basis,the structure invariance theory and speed compensation control are applied to the restraint of redundant force. The results of simulation and bench test show that the control strategy proposed for resistance loading can effectively raise the loading accuracy and reduce the effects of redundant force under disturbance.