电液耦合的商用车新型智能转向系统机理研究

A new intelligent electro-hydraulic coupling steering system for commercial vehicle is researched and developed. This kind of steering system integrates with electric power steering and hydraulic power steering, and provides a kind of energy-saving steering system by the electro-hydraulic coupled control. It can achieve functionalities with alterable assist effort, active return ability, self-parking, lane keeping and intelligent driving. To realize all the above functionalities this project will analyze the matching relation of this steering system and the vehicle, establish the whole car dynamic models coupling with the steering system, and then study the effect of the system parameters on the steering performance according to the electro-hydraulic coupled control mechanism. Considering the traffic environment and vehicle state information, the human-machine collaborative decision-making model and its realizing method on the premise of the priority decision of the drivers for the intelligent steering system will be researched. Furthermore, aiming at the following two different working modes, the design and the track feature of the assist characteristic and the motor coordination control is developed at the conventional power mode. Also, the expectation path planning and the hierarchical control structure are focused on at the intelligent steering mode. In conclusion, the study on these issues will provide the basic theories for the design and application of the intelligent steering system for the commercial vehicle integrating of electric power steering and hydraulic power steering.

研究一种电液耦合的商用车新型智能转向技术，该转向系统集成有电动助力转向和液压助力转向，通过电液耦合控制技术，为商用车提供一种节能型转向系统，实现随速变助力特性，并具有主动回正、自动泊车、道路保持和智能驾驶等功能。围绕该转向系统电液耦合控制机理，分析该系统与整车的匹配关系，建立电液耦合作用下的整车及转向系统动力学模型，研究系统参数对转向性能的影响。考虑交通环境、车辆状态等信息，研究驾驶员优先决策下的智能转向系统的人机协同决策模型及其实现方法。针对该转向系统常规助力和智能转向两种工作模式，研究常规助力模式下的助力特性设计与跟踪、电机协调控制，以及智能转向模式下的期望路径规划与分层控制等问题。通过研究上述问题，为同时具有电动助力转向和液压助力转向的商用车智能转向系统的开发与设计提供理论基础。

本项目针对集成电动助力转向和液压助力转向的电液转向系统，研究了该新型智能转向系统的分层控制，分析了该系统与整车的匹配关系与协调机理，为了进一步提高车辆的操纵稳定性、安全性和驾驶员的舒适性，考虑了“人-车-路”耦合作用下的整车-道路动力学及驾驶员行为模型，研究了人机协同作用下系统参数对转向性能的影响。基于驾驶员干预度信息判断驾驶员的转向意图，将转向模式分为常规助力和智能驾驶，并利用以上信息规划轨迹从而得到期望路径。基于分层控制的方法控制转向系统，上层控制通过前馈-反馈控制得到期望的前轮转角，利用滑模控制设计反馈环节；下层控制通过PID控制实现对前轮转角位置的闭环控制，分别利用电流闭环控制电动助力装置，双闭环控制实现对转向执行机构的位置控制。基于人机协同分层控制能够实现的高效节能、助力可变以及车道保持等辅助驾驶功能，对我国汽车的智能化发展具有重要意义。