电动车辆ABS的改进线性二次型最优控制

为充分利用轮毂电机控制精确和响应迅速的优势,提高电动车辆制动防抱死控制的稳定性,提出一种用于轮毂电机电动车辆制动防抱死系统(ABS)协调控制的改进线性二次型最优控制方法.建立电动车辆纵向动力学模型;结合复合制动系统的协调控制策略,分析现有线性二次型最优控制算法无法用于防抱死控制器设计的原因,提出一种通过构造虚拟阻尼量以及无穷小量来建立黎卡提方程的改进型线性二次型最优控制算法,并据此设计了防抱死控制器.在高附着路面、中附着路面和低附着路面3种不同行驶工况,对分别安装有改进线性二次型最优防抱死控制器和滑模防抱死控制器的电动车辆的紧急制动性能进行了仿真分析.结果表明:在不同附着系数路面行驶工况下,改进线性二次型最优控制算法能够有效提高电动汽车防抱死控制系统的控制精度和响应速度.

Improved linear quadratic optimal control of ABS for an electric vehicle

To make the most of control accuracy and fast response of in-wheel motors and improve the stability of anti-lock brake system (ABS) of in-wheel motor driven electric vehicle, a design method of anti-lock controller based on the improved linear quadratic optimal control algorithm was proposed. A vehicle longitudinal dynamics model was established. The coordinated control strategy of composite braking system was applied in examining the reason for the failure of the general linear quadratic optimal control algorithm in the design of anti-lock controller. An improved linear quadratic optimal control algorithm was proposed to design the anti-lock controller through adding some virtual damping and infinitely small terms in the design process of Riccati function, based on which a anti-lock brake was subsequently designed. The control result of the proposed controller was compared with the control result of general sliding mode controller under three different road conditions with low, middle and high adhesive coefficients. Results showed that the proposed improved linear quadratic optimal control algorithm can achieve not only outstanding control accuracy but also fast response.