一种汽车防抱死制动系统的非线性控制方法

Nonlinear control method for automotive anti-lock braking system

针对具有不连续特性的开关阀防抱死制动系统,本文研究了控制器设计方法.首先讨论了开关阀防抱死制动系统增压、保压、减压三种工作模式的动态特性,给出一种具有滑移率连续动态和执行器不连续动态的开关阀防抱死制动系统的数学描述.在此基础上,考虑到应用性和鲁棒性要求,提出一种以系统状态作为切换规则保证系统稳定性的非线性控制器设计方法,其思想是基于Filippov意义下的Lyapunov方法设计两个切换面,将状态空间划分形式作为切换规则,通过切换面选择保证闭环系统的稳定性.为了避免频繁的模式切换,本文进一步将控制目标调整为平衡区域的收敛控制,并讨论了收敛区域大小对闭环控制性能的影响.仿真与实验结果表明本文给出的方法控制参数少,具有高效和平顺的制动性能.

A controller is designed for anti-lock braking system（ABS） with discontinuous characteristics of on/off valves.Firstly,the dynamic characteristics under Increase,Hold and Decrease modes are discussed,and a math description is given for ABS with on/off valves,including wheel slip continuous dynamics and actuator discontinuous dynamics.Considering the requirement on applicability and robustness,an approach for nonlinear controller design is proposed which uses system state as switching law to guarantee the stability.The idea is to develop two switching surfaces using Lyapunov method in the sense of Filippov,and the state space partition is regarded as the switching law,with the stability ensured via switching surfaces selection.Further,to avoid frequent switches,the control objective is modified to the convergence of an equilibrium set,and the influence of the size about the equilibrium set on the closed-loop system performance is discussed.Simulation and experiment tests illustrate that both high braking efficiency and ride quality are obtained with few control parameters.