面向分体式飞行汽车自主对接的自动驾驶底盘运动规划方法研究

Motion Planning Method of Autonomous Driving Chassis for Autonomous Docking of the Split-type Flying Vehicle

飞行汽车是引领汽车行业未来技术发展的战略新兴方向,分体式飞行汽车作为飞行汽车的主流构型之一,由自动驾驶底盘、智能操控座舱和垂直起降飞行器三部分组成,为完成各部分的自主对接和组合,自动驾驶底盘需要沿规划的路径精确行驶至起飞行器正下方。当前运动规划方法缺乏对来自传感器、控制器和执行器等诸多不确定因素的考虑,导致路径跟踪过程中底盘行驶轨迹偏离规划轨迹,难以精确行驶至预定位置,完成对接。为解决这一问题,提出一种基于长短期记忆网络(Long short-term memory,LSTM)车辆模型的自动驾驶底盘轨迹规划方法。采用LSTM网络表征自动驾驶底盘的运动学特性,在此基础上建立车辆运动学模型。基于该模型,构建模型预测控制架构下的滚动时域优化问题。进而采用基于向量加权平均值的优化方法求解该非线性优化问题,得到符合底盘运动学特性的行驶轨迹。基于团队研制的分体式飞行汽车样机,将提出的规划方法进行试验验证。在转弯场景中,采用提出的方法的底盘平均纵向位置偏差、最大纵向位置偏差与传统模型预测控制(Model predictive control,MPC)方法相比分别下降了78.89%、79.64%和86.67%。

Flying vehicles are a strategic emerging direction leading the future technological development of the automotive field.As one of the mainstream configurations of flying vehicles,split-type flying vehicles are composed of three parts:an autonomous driving chassis,an intelligent cockpit,and a vertical takeoff and landing aircraft.To complete the autonomous docking of the two parts,the autonomous driving chassis needs to track accurately along the planned path to the right below the aircraft.The current motion planning methods lack consideration for many uncertain factors such as sensors,controllers,and actuators,resulting in the chassis trajectory deviating from the planned trajectory during path tracking,making it difficult to accurately travel to the predetermined position and complete docking.To address this issue,an autonomous driving chassis trajectory planning method based on long short-term memory(LSTM)vehicle models is proposed.Using LSTM network to characterize the kinematic characteristics of the autonomous driving chassis of a split-type flying vehicle,a vehicle kinematic model is established based on this.Based on this model,a rolling horizon optimization problem under the model predictive control architecture is constructed.Furthermore,an optimization method based on weighted mean of vectors is used to solve the nonlinear optimization problem and obtain a driving trajectory that conforms to the kinematic characteristics of the chassis.Based on the split-type flying vehicle developed by the team,the proposed planning method is experimentally validated.In the turning scenario,the average longitudinal position deviation,maximum longitudinal position deviation,and longitudinal position docking deviation of the chassis using the proposed method are reduced by 78.89%,79.64%,and 86.67%compared to traditional MPC methods,respectively.