为克服道路条件变化与汽车载质量、制动器效能因数和胎压等参数摄动及因忽略系统非线性因素而出现的未建模动态特性给汽车制动防抱死系统(ABS)控制带来的不良影响,提高其鲁棒性和控制精度,运用汽车动力学理论,建立了ABS系统的数学模型并进行了适当简化。采用混合灵敏度方法设计了基于滑移率控制的ABS系统日。鲁棒控制器。利用Matlab/Simulink对所设计的鲁棒控制系统进行了仿真,并与传统PID控制作了对比分析。结果表明,ABS鲁棒控制器在控制精度、鲁棒稳定性及响应时间等方面都优于传统PID控制;在汽车载质量、制动效能因数和道路条件等发生变化的情况下,ABS鲁棒控制器均能承受参数变化的不确定性,并将车轮滑移率有效地控制在期望值附近,明显提高了整车的制动性能。
In order to overcome the adverse effects on the antilock braking system (ABS) control of vehicle, caused by the change of road conditions and the perturbation of such parameters as load, braking efficiency factor and tire pressure, as well as unmodeled dynamic characteristics usually due to neglecting the nonlinear factors in ABS models, and to improve the robustness and accuracy of ABS control system, an ABS model is built and simplified with vehicle dynamics theory. By using mixed sensitivity method, an H∞ robust controller based on slip ratio control is designed, and on which a simulation with Matlab/Simulink is performed and a comparative analysis with traditional PID control is made. The results show that the designed controller is superior to PID control in control accuracy, robust stability and response time, and can accept the uncertainty in model parameters of load, braking efficiency factor and road conditions, and effectively keep the tire slip ratio around the desired value, obviously improving the braking performance of vehicle.