基于LQG-PID的EPS系统最优控制

Based on LQG-PID Optimal Control of EPS System

汽车电动助力转向(EPS)系统因受系统本身模型参数不确定性、路面随机激励和转矩传感器的测量噪声等干扰因素的影响,使用传统PID控制方法已不能满足对其精确控制的要求。通过构建EPS系统的数学模型,并加入随机干扰信号,建立系统的状态空间表达式,在PID控制的基础上设计线性二次型高斯(LQG)状态反馈控制器,即优化的LQG-PID控制。以能耗最小为目标函数,运用Matlab/Simulink对EPS系统进行仿真分析。仿真曲线表明:应用LQGPID控制方法能有效减小系统受到的随机干扰,使能耗及电动机的实际助力电流与目标电流的误差最小,提高了EPS系统的鲁棒性。

Due to the system itself uncertainty of model parameters, road random excitation and torque sensor measurement noise and other factors interference, using traditional PID control methods cannot meet the precise control of the Electric Power Steering （EPS） system. By building a mathematical model of the EPS system and adding random noise signal, we created a system of state space expres- sion and designed linear quadratic Gaussian on the basis of PID control （LQG） state feedback control- ler that was optimized LQG-PID control. With minimum energy consumption as objective function, u- sing Matlab/Simulink simulation analysis of EPS system, the resulting simulation curves show： appli- cation of LQG-PID control method can effectively reduce the system subject to random disturbances, the error of the actual energy consumption and electric motor assist current and target current mini- mum, which improves the robustness of the EPS system.