电动轮驱动汽车动载冲击下空间失稳能量转化机制与馈能回稳控制方法

In-wheel motors drive electric vehicle has the advantages of excellent dynamic stability control, however the unsprung dynamic load is too large in the transient steering with driving/braking on uneven roads. In these situations, the wheels might be easily lead to jump and the tires will lose adhesion, which makes the vehicle occur spatial instability. The applicant has revealed the evolution mechanism of this process and put forward an anti-rollover control method based on the drive/braking torque distribution, but the control effect is limited by the drive systems power and the energy consumption is obvious, which difficult to meet the safety and energy saving demands of the vehicle. For the purpose of resolving the above problems, the project will explore the vehicle safety control method based on the vibration and braking energy feedback. The following research will be done in this project. The effects of different suspension configurations, performance parameters and non-suspension mass ratio on the vehicle space stability is analyzed, and the integrated design and optimization design of the energy-regenerative suspensions in the in-wheel motors drive vehicle is carried out. The vehicle multi-coupled nonlinear dynamic model and bond graph model that coverers the models of uneven road, electric wheels, energy-regenerative suspensions and flexible body is established, which is used to accurate describe the mechanism of the transformation between kinetic energy and potential energy and the energy dissipation in the overall process from plane instability to spatial instability. The vehicle stabilization control method is proposed and verified by combining the in-wheel motors regenerative brake, the suspensions regenerative energy and attenuation vibration and supplementing the front wheels angle active control. This project strives to make an innovative breakthrough in constructing the theoretical system of the space stability decoupling control of in-wheel motors drive vehicle based on the integration of in-wheel motors, energy-regenerative suspensions and active steering system.

电动轮驱动汽车具有优越的动力学控制功能，但其在不平路面瞬态转向过程中簧下动载冲击过大，车轮跳动和路面附着力骤变极易引致整车空间失稳。申请人已对这一过程的演化机理进行了理论揭示并提出了基于驱/制动力矩分配的防侧翻控制方法，但该控制效果有限且耗费电能，难满足整车安全节能诉求。为解决此问题，本项目将探索基于振动和制动能量回馈的整车安全性控制方法，首先分析不同悬架构型、性能参数及非悬挂质量占比对车辆空间稳定性的影响，实现馈能悬架在电动轮驱动汽车上的集成设计与优化设计；建立涵盖不平路面-电动轮-馈能悬架-柔性车身的多重耦合非线性动力学模型和键合图模型，精确描述整车空间失稳全过程的动/势能转换与能量耗散机制；提出并验证结合轮毂电机回馈制动与悬架馈能减振并辅以前轮转角主动调控的整车回稳控制方法。本项目力争在基于轮毂电机、馈能悬架与主动转向系统协同的电动轮驱动汽车空间稳定性解耦控制理论方面取得创新性突破。

电动轮驱动汽车具有优越的动力学控制功能，采用轮毂电机直接驱动车轮是其代表构型，但过大的簧下质量会在不平路面上产生明显的动载冲击，从而引起车轮跳动和路面附着力骤降，还会造成驱动系统损伤甚至失效，上述现象在车辆瞬态转向过程中极易引致整车空间失稳。为解决此问题，本项目从电动轮驱动汽车整车集成设计与空间稳定性控制、单侧驱动系统失效安全控制以及电动轮驱动系统创新设计等多个方面进行了深入研究。为了降低电动轮驱动汽车不平路面上的动载冲击，分析了不同悬架构型、性能参数及非悬挂质量占比对车辆空间稳定性的影响，开展了馈能悬架优化集成设计，有效提升了车辆的稳定性和平顺性，并具备了振动能量回馈能力；建立了涵盖不平路面-电动轮-馈能悬架-柔性车身的多重耦合非线性动力学模型和能量转化模型，揭示了多层次耦合作用下电动轮驱动汽车空间失稳演化机理和能量转化机制，提出了其由平面失稳向空间失稳进行动/势能转化的可控域判据，将电动轮驱动汽车的稳定性分析从平面维度拓展到了空间维度；提出并验证了结合轮毂电机回馈制动与悬架馈能减振并辅以前轮主动转向的整车回稳控制方法，在动/势能转化可控域内通过底盘协同控制改变能量传递路径，有效提高了瞬态转向工况车辆空间稳定性；针对电动轮驱动汽车单侧驱动系统失效导致的失稳问题，提出并验证了基于正常驱动系统转矩协调和制动系统制动压力主动补偿的协同控制方法，保证了驱/制动工况车辆的方向稳定性和制动效能；为了保证单侧电动轮驱动系统失效后车辆的持续高速行驶能力，发明了集中式/分布式耦合纯电和混合动力驱动系统乃至所用新型同步器，对系统构型和控制策略进行了优化，保证了模式切换的平顺性和混联驱动的高效性。项目在电动轮驱动汽车底盘协同空间稳定性控制和集中式/分布式耦合驱动技术创新应用上取得了可喜的理论成果，从结构和控制两方面着手突破了阻碍电动轮驱动系统应用的技术瓶颈，为推动其大规模产业化奠定了理论基础。