基于改进切换函数的电动轮汽车ABS滑模控制

ABS sliding mode control for electric-wheel vehicle based on improved switching function

虽然滑模变结构控制策略的快速性和鲁棒性能够满足紧急制动时车辆的控制要求,但控制器的切换作用使系统出现奇异点,为最佳滑移率的在线辨识带来了困难.针对这一问题,提出一种改进切换函数的滑模变结构控制策略,利用车轮工作状态与滑移率变化趋势之间的关系,动态优化控制器的切换函数,使滑模面逼近最佳滑移率.仿真结果以及硬件在环实验表明,该方案可有效提高车辆的制动性能,并对路面变化引起的严重非线性具有良好的自适应能力.

Although the rapidty and robustness of sliding mode variable structure control strategy can well satisfy the control requirement during the emergency braking of vehicle, the singularity of system which is caused by the switching effect of controller brings the difficulty for the online identification of optimal slip ratio. To solve the above-mentioned problem, an sliding mode variable structure control stratagy with the improved switching function was proposed. With the relationship between the operating status of wheel and the change trend of slip ratio, the switching function of controller was dynamically optimized, which made the sliding surface approximate to the optimal slip ratio. The simulated results and hardware-in-loop experiments show that the proposed scheme can efficiently improve the braking performance of vehicle, and has good adaptive ability to severe nonlinearity caused by the change of road condition.