车辆稳定控制中的合力计算与分配

Force calculation and distribution in vehicle stability control

中文关键词  车辆运动稳定控制  合力可行域  轮胎力分配

英文关键词  vehicle stability control  feasible region of resultant force  tires force distribution

中文摘要

      控制地面作用于车辆的纵侧向合力与横摆转矩并将其分配到4个车轮, 是车辆平面运动稳定控制的方法之一. 路面的附着极限决定了合力与横摆转矩的可行域, 是该方法的约束条件. 本文分析了轮胎的受力特点, 在摩擦椭圆理论的基础上, 给出了简化的纵侧向力耦合关系. 利用非线性规划方法和大量的数值计算, 解决纵向合力与横摆转矩可行域的实时估计问题. 构造了一种控制结构, 外环控制器计算可行的纵向合力与横摆转矩; 内环控制器首先将纵向合力优化分配到4个车轮, 然后通过调节前轮转角使横摆转矩跟踪期望值. 仿真结果表明, 采用本文提出的方法对车辆进行控制, 能够实现横摆角速度的快速准确跟踪, 并使车辆具有良好的操纵稳定性.

英文摘要

      Calculating the resultant longitudinal/lateral force and the yaw moment, then distributing them to tires is one of the vehicle planar motion stability control methods. The road adhesion limits the feasible region of the resultant force and the yaw moment, which is a constraint of this strategy. The tire dynamical characteristics are analyzed and a simplified longitudinal/lateral force coupling relationship is proposed based on the Friction Ellipse Theorem. A real time estimation method of the longitudinal force and the yaw moment feasible region using the nonlinear programming and the numerical calculations is presented. Finally, control structure is established. The outer loop controller calculates the feasible longitudinal resultant force and the yaw moment; while the inner loop distributes the longitudinal resultant force to the tires optimally, then the real yaw moment is controlled to follow the expected value by adjusting front-wheels’ steering angles. As shown in the simulations, utilizing the proposed technique in this paper to control the vehicle leads to a rapid and accurate tracking performance of the yaw rate, good handling stability.