集成电动助力转向功能的汽车主动前轮转向系统机理研究

On the basis of automobile active front steering (AFS) system, a novel AFS system has been developed by integrating the technology of electric power-assisted steering (EPS). It can not only perfectly integrate steering road feel and steering portability, but also can satisfactorily harmonize the contradictory relationship between security performance and agility capability. Therefore, it will be the main developing direction of automotive power steering technology in a certain period of the future..Firstly, the dynamic models for the novel AFS and vehicle are built. Secondly, analyzing coupling relationships between the displacement transfer characteristic and the force transfer characteristic, the force-displacement coupling control strategy for the novel AFS system is studied. Then, due to the problem of parameter perturbation and sensor failure, a integrality robust fault-tolerant control strategy for the uncertainty system to the sensor failure1 is researched. Finally, on the basis of analyzing the matching relation of the novel AFS system, the structure parameters and force-displacement transfer characteristics of the system are optimized by using multidisciplinary optimization method. The aspects of man-machine engineering, mechanical engineering and automobile active safety are considered during the optimization. Researching the problems mentioned above, a theoretical basis can be provided for the novel AFS system integrated with the functions of AFS and EPS.

在汽车主动前轮转向系统基础上，集成电动助力转向技术，开发一种新型主动前轮转向系统，使其同时融合主动转向和电动助力转向功能，不仅能实现汽车转向路感和轻便性的协调统一完美结合，而且还能使汽车的安全性和灵活性完美结合，将是未来一定时期内汽车动力转向技术的主要发展方向。.建立新型主动前轮转向及整车系统动力学模型；分析系统位移传递特性与力传递特性的耦合关系，研究新型主动前轮转向系统力与位移耦合控制策略；针对系统存在的参数摄动和传感器失效问题，研究不确定性系统对传感器失效具有完整性的鲁棒容错控制规律；研究新型主动前轮转向系统的匹配关系，从人机工程学、机械工程学、汽车主动安全性等方面入手，运用多学科协同优化方法对系统的结构参数、力与位移传递特性进行优化。.通过研究上述问题，为同时具有主动转向和电动助力转向功能的新型主动前轮转向系统的开发与设计提供理论基础。

新型主动前轮转向系统将是未来一定时间内汽车动力转向系统的应用和发展方向。本项目开发了汽车新型主动前轮转向系统，将与驾驶员神经肌肉动力学特性相关的转向操作行为纳入了闭环系统，建立了涵盖驾驶员前视预瞄特征和神经肌肉动力学特性的人-车-路闭环系统动力学模型；考虑各个系统之间的耦合因素，研究了基于层次分解理论的系统多学科优化设计方法；分析了转向传动比对汽车转向特性的影响，设计了汽车在不同工况下的变传动比规律；考虑汽车行驶时路面附着系数变化、轮胎非线性特性和外界干扰，基于H2/H∞混合鲁棒控制理论设计了车辆稳定性控制策略；研究了驾驶员路感的产生机理及理想转向盘力矩的影响因素，分析了主动前轮转向系统位移特性对力特性的影响，研究了变传动比规律下的驾驶员路感变化关系，设计了转向盘力矩前馈补偿策略；研究了传感器、控制器和电机容错控制之间的优先级及协调关系，提出了主动前轮转向系统鲁棒容错控制策略。本项目的研究工作为前轮主动转向系统的设计与开发提供了理论基础。