@article{title="A terminal sliding mode based torque distribution control for an individual-wheel-drive vehicle",
author="Pan Song, Chang-fu Zong, Masayoshi Tomizuka",
journal="Journal of Zhejiang University Science A",
volume="15",
number="9",
pages="681-693",
year="2014",
publisher="Zhejiang University Press & Springer",
doi="10.1631/jzus.A1400101"
}
Abstract: This paper presents a torque distribution method for an individual-wheel drive vehicle, in which each wheel is controlled individually by its own electric motor. The terminal sliding mode technique is employed for the motion control so as to track the desired vehicle motion obtained by interpreting the driver’s commands. Thus, finite-time convergence of the system’s dynamic errors can be achieved on the terminal sliding manifolds, as compared to the well-used linear sliding surface. By considering nonlinear constraints of the tire adhesive limits, a simple yet effective distribution strategy is introduced to allocate the motion control efforts to each of the four wheels. Through the use of a high-fidelity CarSim full-vehicle model, vehicle stability and handling performance of the proposed controller is evaluated in both open- and closed-loop simulations.
基于终端滑模控制的四轮独立驱动汽车转矩分配方法
研究目的：四轮独立驱动汽车四个车轮的电机转矩可以正、反向输出，有必要对其底盘集成控制系统进行针对性设计以保证各车轮间的协调运作。集成控制系统一般可以分为上层运动控制器和下层力分配器。对于运动控制器的设计，同类研究一般采用滑模控制方法来处理汽车运动的非线性特征，其中终端滑模控制因具有高的稳态精度和有限时间收敛的特点而成为研究热点。对于力分配器的设计，通常方法不能在保证运算效率的同时考虑到执行器的约束，从而很难应用于实际。本文采用终端滑模控制方法来设计运动控制器，通过分析驾驶员操作行为从而更好地追踪理想的车辆运动目标；并提出一种简单有效的转矩分配控制策略，通过考虑轮胎附着极限从而将运动总力分配至四个车轮上。
创新要点：本文创新性地将终端滑模控制应用到底盘集成控制系统以实现车辆纵向、侧向及横摆运动的联合控制；本文提出了一种新颖的转矩分配控制策略，将复杂的有约束控制分配问题分解至若干个简单的无约束分配子问题。
研究方法：本文采用分层式协调控制方案（图1），应用非奇异和全局快速终端滑模控制方法设计运动控制器，提出一种基于伪逆矩阵的有约束转矩分配策略，应用驾驶员最优预瞄加速度模型来描述和分析人-车闭环系统的运动响应，通过MATLAB/Simulink和CarSim的联合仿真对所设计的四轮独立驱动汽车转矩分配方法进行对比验证。所设定的三个仿真工况包括：开环方向盘角阶跃输入（图6、7及表2）、闭环双移线工况（图8-10）和闭环对开路面制动（图11-15），分别用以测试车辆横摆、侧向及纵向方向上的动力学响应。
重要结论：本文提出的基于终端滑模控制的四轮独立驱动汽车转矩分配方法将车辆的稳态转向特性由不足转向转变为中性转向，驾驶员从而能更容易地操纵车辆而不需要对汽车的非线性响应做出额外的转向补偿。与此同时，该分配方法在不影响车辆侧向稳定性的前提下可以准确地响应驾驶员的加速/制动意图。仿真结果表明终端滑模控制器相比传统滑模控制方法在车辆纵向、侧向、横摆方向上的运动控制效果均有一定程度地提高，而有约束的力分配器更可以明显地提高车辆的操纵性和稳定性。综合评价表明，所提出的基于终端滑模控制的四轮独立驱动汽车转矩分配方法获得了最佳的控制性能，符合设计要求。
汽车动力学；底盘集成控制；驾驶员模型；终端滑模控制；控制分配
Darkslateblue:Affiliate; Royal Blue:Author; Turquoise:Article
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