集成主动转向系统的分布式驱动电动汽车纵横向运动综合控制研究

Integrated longitudinal and lateral motion control system can improve the vehicle handling stability and energy efficiency by controlling the drive/brake system and the steering system. For the integrated longitudinal and lateral motion control of distributed EV, there are some problems in the existing researches, such as the control system is incomplete, the accuracy and robustness of the vehicle state estimation is not high enough, the performance index of tire force distribution is not optimal, and the accuracy of inverse tire model is limited. Considering these problems, for the distributed EV integrated with active front steering system, an integrated longitudinal and lateral motion control system will be proposed in order to improve the handling stability and energy efficiency. The key technologies, including vehicle state estimation, optimum tire force distribution and tire force control will be studied. The key vehicle states estimate method such as longitudinal velocity and vehicle sideslip angle will be established by integrating the kinematic and dynamic estimation method, the longitudinal and lateral tire forces allocated method will be established based on the optimization of tire workload and tire energy dissipation respectively. The desired tire forces will be transformed to tire slip ratio and sideslip angle and the longitudinal force and lateral force will be decoupled. A sliding mode controller and a feedforward/feedback combined controller will be established for the control of the tire slip ratio and sideslip angle respectively. The simulation and field test in different operating conditions will be carried out. It will have important theoretical research value and application prospect to improve the vehicle handling stability and energy efficiency.

纵横向运动综合控制技术通过协调纵向的驱动/制动系统与横向的转向系统，综合提高车辆的操纵稳定性及经济性等性能。针对分布式驱动电动汽车纵横向运动综合控制存在的控制体系不够完善、状态估计算法准确性与鲁棒性不高、纵横向力分配算法优化目标单一、轮胎逆模型计算精度较低等问题，提出集成主动转向系统的纵横向运动综合控制方法，对车辆状态估计、纵横向力分配、纵横向力控制等核心问题展开研究。建立融合运动学与动力学状态估计方法的车速和质心侧偏角估计方法；建立基于轮胎负荷率优化和耗散能优化方法的各轮纵横向力优化分配方法；通过轮胎逆模型将纵横向力控制目标转换为轮胎滑移率与侧偏角控制目标，实现纵横向力间的解耦，并建立应用滑模算法的滑移率控制器和基于前馈与反馈组合的侧偏角控制器，实现对轮胎滑移率及侧偏角的控制；搭建仿真与实车试验平台验证理论研究的可行性。对提升汽车的操纵稳定性与经济性具有重要的理论研究价值和工程应用前景。

通过研究，进一步深化了对分布式驱动电动汽车纵横向综合运动的认识，其是一个具有冗余的控制自由度的装配有独立驱动、制动和主动转向等多执行机构的复杂动力系统，包含物理饱和约束和轮胎滑移安全约束等复杂约束，是一个受垂向影响的侧向-纵向复杂耦合的非线性控制系统。项目针对分布式驱动电动汽车系统中驱动、制动、转向等多个执行器间的动作耦合及制约问题，研究了复杂约束下转矩协调优化控制涉及的状态参数观测算法、转矩控制分配方法、转矩分配控制方法等三个核心问题。通过分析分布式驱动电动汽车各驱动电机独立控制及其多信息融合的特征，采用分层式控制分配策略，设计了状态参数观测和转矩协调控制结构；研究了动力学状态参数观测算法，设计了多执行器转矩协调优化控制方法；解耦分布式驱动转矩之间的动力学关系，降低了整体优化策略的系统维数，解决了多个执行器难以协同工作的问题；综合改善了分布式驱动电动汽车的纵向驱动能力和横向稳定性能，实现了“安全-动力-节能”的多目标需求。累计发表论文11篇，申请发明专利5件，毕业硕士研究生4人。产生了良好的经济和社会效益。