车辆驱动电气化背景下的轮胎力协调控制理论关键问题的研究

Integrated vehicle dynamic control is the key approach to optimally managing the multiple chassis control subsystems, i.e. avoiding conflicts and coordinating subsystems to achieve the best performance of vehicle dynamics. However, with energy efficiency being of the highest interest, dynamic controller designers for electric vehicles are facing a new challenge: how to give attention to both energy efficiency and dynamics performance? There are still many unclear points in the current research findings on this topic. This proposal is to answer parts of this challenge, with the main focus on the coordination control theory and algorithm in electric vehicles. The prototype has active controlled braking, active steering, and independently driven hub motors in wheels. Firstly, by theoretical analysis, CarSim co-simulation and road tests, the mechanisms of control conflict among hub motor driving, motor regenerative braking, hydraulic braking and active steering, are provided and discussed. Based on this, the coordination strategy is derived and provided for system coordination assessment. Secondly, by taking the weighted cost function including both dynamics performance and energy efficiency, and adopting an adaptive fuzzy decision method and nonlinear global optimization theory, a novel tyre force coordination control design methodology is formulated. One most important advantage is that it can self-adaptively re-assign weights to different system actuators. This re-configurability feature owes to the previously designed potential assessment module, which is based on precise subsystem and vehicle models. Thirdly, the coordination control algorithm is refined to be more computing efficient, thus allowing real time application. The fundamental and key rule adopted in this research is to replace fully online optimization computing with combined optimization, i.e. offline optimization and online pattern matching and synthesis. Finally, the proposed control methodology is to be validated and improved through soft-in-loop and rapid control prototyping approach. The research findings of this project may provide some theoretical guidelines and insights for the R&D of dynamic control systems for future electric vehicles.

随着汽车底盘电控系统数目的急剧增加，集成控制是避免子系统冲突、统一协调控制动作的重要途径。而以能效为重要指标的电动车辆，在其动力学控制开发方面则面对着新的挑战：如何兼顾节能性和运动性能？对此问题的研究，学界和业界仍存在着或多或少的缺陷和不足。项目以装备有独立驱动、独立制动以及主动转向等多执行器系统的未来先进电动车辆为对象，通过理论分析、仿真和试验研究，阐明独立电机驱动及再生制动与液压制动、转向执行器间的基本冲突机理，提出可行的总体协调策略。以运动控制性能、节能性综合最优为目标，采用自适应模糊决策和非线性全局优化理论，提出一种能根据执行器控制潜力自适应、实现控制重构的轮胎力协调控制设计方法。采用离线优化、在线匹配的方法，在保证精度前提下提高了控制算法的实时性，并用软件在环仿真和快速原型试验手段进行验证完善。研究成果可为今后电动车辆运动控制系统的设计研发提供理论依据与借鉴思路。

安全、节能、舒适是汽车先进技术的三大指标。项目以装备有独立驱动、独立制动、主动转向、车轮外倾主动控制等多执行器系统的未来先进车辆为对象，通过理论分析、仿真和试验研究，开展了三部分研究内容，即：车辆纵向和侧向子系统冲突机理和冲突协调机制、车辆轮胎力协调控制策略和方法、算法改进和验证。研究表明：.(1)整车动力学的耦合，尤其轮胎力学的耦合，是转向、驱动、制动、悬架等系统冲突的根源，也是实现多系统动力学协调控制的立足点。.(2)驱动、制动和转向的冲突主要体现在轮胎力耦合、横摆力矩耦合、能量回收等三个方面，协调控制算法应综合考虑经济性、操纵稳定性、舒适性、安全性等多目标。.(3)驾驶员转向意图辨识结果有利于改善稳定性控制的性能，可降低驾驶员的心理和生理负荷，提高驾驶员-车辆整体系统的稳定性。.(4)电机再生制动回收能量的效率与初始速度、制动强度、电池-电容SOC等状态条件紧密相关，再生制动及其与其他子系统的协调控制需要解决瞬态性强、约束条件复杂的难点。将再生制动作为操纵稳定性主动控制执行器时，应特别注意考虑其不同工况下的动态响应特性对算法效果的影响，注意保证控制算法的工况适应性和鲁棒性。.(5)对城市用小型电动车辆而言，车轮外倾主动控制有望成为重要的动力学控制执行器之一。协调控制设计时应综合考虑最大可变角度、性能提升潜力、占用空间、能耗、轮胎偏磨等多目标的权衡。..研究成果可为今后新能源车辆整车控制系统的设计研发提供理论依据与借鉴思路。.