Abstract: Aiming at the response time delay problems caused by signal transmission, mechanical clearance and friction of the SBW systems, a 2DOF IMC was designed to improve the angle tracking accuracy. The time delay model and the SBW model were established and combined as the nominal model. In order to avoid non-minimum phase terms, an all-pole approximation method was adopted to linearize the time delay model, so the tracking controller and the anti-interference controller might be solved. Compared with the 2DOF IMC without using a nominal model with time delay and the classical PID control, MATLAB/Simulink simulation results show the influences of time delay on the tracking performance of the three methods. The effects of time delay on the tracking performance of the 2DOF IMC using the all-pole, Taylor and Padé approximation methods were compared respectively. Finally, the bench test results of the SBW systems show that the 2DOF IMC based on the all-pole approximation has higher tracking accuracy and better adaptability to time delay.

Key words: steer-by-wire (SBW), delay, two degree-of-freedom(2DOF), internal model control(IMC), all-pole approximation

摘要： 针对线控转向系统中由于信号传输、机械间隙和摩擦等因素引起的响应延迟问题，设计了二自由度内模控制策略以提高转角跟踪精度。将延迟模型与线控转向系统模型相结合，构建新的名义模型，为避免引入非最小相位项，采用全极点近似方法将延迟环节线性化，求解跟踪控制器和抗干扰控制器。与名义模型不含延迟环节的二自由度内模控制以及经典PID控制相比较，通过MATLAB/Simulink仿真给出了延迟量对三种方法跟踪性能的影响。比较了延迟量对采用全极点近似、Taylor近似和Padé近似的二自由度内模控制跟踪性能的影响。经线控转向台架试验验证，采用全极点近似的二自由度内模控制跟踪精度较高，对延迟的适应性较好。

关键词: 线控转向, 延迟, 二自由度, 内模控制, 全极点近似