多轴分布式驱动无人车辆极限操纵状态整车集成控制方法

Integrated Control Method of Multi-axle Distributed Driving Unmanned Ground Vehicle in Handling Limit

包络线控制起源于航空航天工业,它提供了飞行状态的安全保障和机动边界,为飞行器控制带来了良好效果。基于8×8多轴分布式驱动无人车辆和包络线方法核心思想,提出一种将车辆推向极限的整车动力学控制器。通过建立轮胎滑移圆提出一种新的方法以用于评估车辆驱动力状态,并将轮胎滑移状态与车辆“g-g”图相结合,用来实现无人驾驶状态下逼近车辆操纵能力极限,发挥车辆动力性能与灵活性能,同时确保在轨迹跟踪时的跟踪精度,精准高效地完成平台任务。考虑外界环境不确定扰动与因素变化对极限状态下车辆稳定性影响,基于车辆横向动力学模型的稳定特性分析,获得不同条件下稳定域相平面,并探索其变化机理、归纳数学描述表达式。通过对车辆稳定相平面的分析,提出以车辆横摆力矩为输出的稳定保持控制器。针对上层控制器驱动力与横摆力矩的输出,设计下层转矩分配控制策略,通过冗余执行器的最优分配实现整车性能发挥。整车集成控制策略部署于一辆8×8原型试验车辆,在越野路面上进行多项科目测试,试验结果表明:在高速条件下,无人车在轨迹跟踪中具有更好的动力性能和安全性能。

Envelope control originated in the aerospace industry,which provides the safety guarantees and movement limit and brings a better performance in aircraft control.A vehicle dynamics controller,which pushes the vehicle in handling limit,is proposed based on 8×8 distributed driving unmanned ground vehicle and the core idea of envelope method.Firstly,a novel method is proposed to evaluate the driving force status of vehicle by establishing a tire slip circle.The tire slip status and“g-g”diagram are combined to achieve approaching the vehicle handling limit under autonomous driving,and to perform the vehicle's mobility and maneuverability.On the other hand,the controller is used to insure the tracking accuracy during trajectory tracking which can complete tasks more accurately and efficiently.Subsequently,in considering the impact of external environmental uncertainties on the stability of vehicles in extreme states,the stability phase planes under different conditions are obtained based on the analysis of stability characteristics of vehicle lateral dynamics model,and the mathematical expressions of them are summarized according to change mechanism.A stability maintaining controller with yaw moment output is proposed by analyzing the stability phase plane.Finally,based on the output of the upper-level controller,a lower-level torque distribution control strategy is designed to achieve full performance through the optimal allocation of actuators.The integrated control strategy is deployed on an 8×8 prototype vehicle and was tested with multiple subjects under the condition of off-road.The test results show that the vehicle has better dynamic performance and safety in trajectory tracking under high-speed condition.