多轴商用车抗侧倾液压互联悬架与车轮转向系统的协同控制研究

Interconnected suspensions (ISs) provide distinct advantages with regard to body control, and have become effective solution to improve handling performances. However, the conundrum of collaborative control between IS and other chassis active safety systems is the bottleneck that hinders its development. When tire couples vertical and lateral forces yielded by IS and wheel steering, mismatched control strategies would affect control performances, or even aggravate vehicle instability in severe case. This project chooses multi-axle commercial vehicle as a medium to investigate the coordination control strategies between hydraulically interconnected suspension (HIS) and wheel steering systems. It is firstly to study the mechanism of roll instability of vehicle with HIS, and analyse mechanism of lateral instability subject to load transfer among axles. The multi-dimension unstable boundary model is established, and thus the warning mechanisms of roll and lateral instability are developed. Hierarchical collaborative control allocation (HCCA) method is then proposed for stability control of roll and lateral motions in order to extend stability margin realized by independently control of each actuator’s pressure and wheel steering angle. Finally, mathematical simulation and rapid controller prototyping test are employed to evaluate the effectiveness and robust of the HCCA and pressure tracking methods for full vehicle and actuator, respectively. The proposed theory and method for collaborative control of HIS and wheel steering of multi-axle commercial vehicle are of great significance to improving the collaborative control theory and method of chassis’ active safety system.

互联悬架在车体姿态控制方面具有独特优点，已成为提升操稳性能的有效手段，但互联悬架与底盘其他主动安全系统协调控制难题是阻碍其发展的瓶颈。当轮胎将互联悬架与车轮转向各自产生的垂向和侧向力耦合时，失配的控制策略轻则影响控制性能，重则加剧车辆失稳。项目以多轴商用车为载体，研究抗侧倾液压互联悬架和车轮转向系统协同控制策略。首先，研究装有液压互联悬架车辆的侧倾失稳机理，同时分析具有轴间载荷转移的车辆横向失稳机理，建立多维失稳边界模型，提出侧倾和横向失稳预警机制；其次，建立侧倾和横向运动稳定性的分层协同控制分配策略，利用各作动器腔内压力和车轮转角独立可控，实现车辆侧倾和横向稳定裕扩展；最后，采用数值仿真和快速控制原型实验，分别验证整车控制策略和作动器压力跟踪方法的有效性和可靠性。本项目建立的多轴商用车液压互联悬架和车轮转向主动协同控制理论和方法，对完善底盘主动安全系统的协同控制理论和方法具有重要意义。

液压互联悬架在多轴商用车车体控制方面具有独特优点，其与转向系统协同控制对扩展侧倾和横向运动稳定裕度具有重要意义。本项目研究了质量不确定性、钢板弹簧迟滞非线性、轮胎侧偏刚度非线性、非对称液压作动缸过驱动、恶意网络攻击等对协同控制稳定裕度的影响。建立了多轴商用车机械液压耦合动力学模型，结合附加运动模式刚度和阻尼剖析液压互联悬架系统提升稳定性机理。针对迟滞非线性板簧悬架系统，提出了系统状态与路面扰动的同步估计方法。借助自适应力触发机制、设计升降压转换器电流调节与超级电容可变终端电压阈值融合技术，实现了车体振动低能耗控制与轮侧振动高效馈能。发展了悬架与转向分层协同控制策略，设计了障碍李雅普诺夫反演控制、天棚阻尼控制、静动态输出反馈控制等上层目标力控制器设计实现车体水平运动控制、提高隔振性能、改善垂向振动舒适性、跟踪动态避障轨迹等功能，提出了时变非线性液压系统的多电磁阀开度预测协同调节管理、投影自适应反演等下层力跟踪控制策略。此外，为增强网络化液压互联悬架与转向协同控制系统抵御有害攻击的安全性，提出了容忍有限能量网络攻击与提高控制指令网络传输效率的弹性触发控制策略。研究成果对液压互联悬架推广应用、提高车载控制系统网络安全性具有重要意义。