非线性ABS系统全局滑模控制律设计

传统的ABS系统等速趋近律滑模控制器存在滑移率抖振和鲁棒性差的问题，本研究提出了一种改进的指数趋近律，即通过增加自然对数函数项，使系统的滑模运动在制动过程开始时即位于滑模面或贴近滑模面。应用Lyapunov稳定性判据证明了新设计控制器的稳定性。仿真验证结果表明，所提出的非线性全局滑模控制方案，其车轮滑移率保持在理想值附近，消除了抖振现象，提高了控制系统的鲁棒性和车辆的制动性能。

DESIGN OF GLOBAL SLIDING MODE CONTROL LAW FOR NONLINEAR ABS SYSTEM

The traditional sliding mode controller of constant speed approach law of ABS system has the problems of sliding rate chattering and poor robustness. Therefore, an improved exponential approach law is proposed, that is, by adding the natural logarithm function term, the sliding mode motion of the system is located on the sliding film surface or close to the sliding mode surface at the beginning of the braking process. Lyapunov stability criterion is applied to prove the stability of the new controller. The simulation results show that the proposed nonlinear global sliding mode control scheme keeps the wheel slip rate near the ideal value, eliminates the chattering phenomenon, and improves the robustness of the control system and the braking performance of the vehicle.