拖挂式大载荷特种车辆导航控制系统设计与试验

针对拖挂式大载荷特种车辆作业自动化以及高精度安全作业需求,以大载荷牵引车为对象,设计了一套拖挂式机组自主导航控制系统。车载程控系统采用模块化分布式系统,通过CAN总线实现系统内各模块间通信,远程运管平台与车载程控终端之间采用TCP协议进行数据通信,实现远程运管平台与车载程控系统间信息交互。建立拖挂式特种车辆的运动学模型,分析牵引作业时被牵引机具的牵引状态和最小转弯半径。针对传统纯追踪算法中固定前视距离缺陷,本文根据当前牵引车实时速度、追踪路径曲率、航向等信息动态计算前视距离,将固定前视距离改进为动态前视距离追踪,由单参数变为多参数进行优化控制参数,显著提高了轨迹追踪精度;使用随机森林算法对轨迹追踪数据进行特征提取,根据各个特征重要性指标权重,修改算法参数。在试验场地为水平倾斜度最大为2°的空旷的水泥跑道上,牵引车质量2t,被牵引机具质量10t、长22m,且牵引机组设计要求最大行驶速度为6km/h、最大横向偏差为50cm。根据复杂路径试验与数据分析,系统纠偏响应时延最大为84ms,牵引机组绝对横向误差最大为37.14cm,平均绝对误差为14.91cm,满足大载荷拖挂作业中的实际应用要求。

Design and Experiment of Navigation Control System for Trailer Special Vehicle

Aiming at the operation automation and high-precision safety operation requirements of trailer-type large-load special vehicles, a set of trailer-type unit autonomous navigation control system was designed for the large-load tractor. The vehicle-mounted program control system adopted a modular distributed system, and the communication between the modules in the system was realized through the CAN bus. The TCP protocol was used for data communication between the remote operation and management platform and the vehicle-mounted program control terminal, so as to realize the information exchange between the remote operation and management platform and the vehicle-mounted program control system. The kinematic model of the trailer-type special vehicle was established, and the towing state and the minimum turning radius of the towed machine were analyzed during the towing operation. Aiming at the defect of fixed foresight distance in the traditional pure pursuit algorithm, the foresight distance was dynamically calculated based on the current real time speed of the tractor, tracking path curvature, heading and other information, and the fixed foresight distance into dynamic foresight distance tracking was improved. The control parameters were optimized for multiple parameters, which significantly improved the accuracy of trajectory tracking;the random forest algorithm was used to extract the features of the trajectory tracking data, and the algorithm parameters were modified according to the weight of each feature importance index. On an open concrete runway with a maximum horizontal inclination of 2° on the test site, the mass of the tractor was 2t, the mass of the towed machine was 10t, and the length was 22m, and the design of the traction unit required a maximum running speed of 6km/h and a maximum lateral deviation of 50cm. According to the long and complex path test and data analysis, the maximum delay of the system correction response was 84ms, the maximum absolute lateral error of the traction unit was 37.14cm, and the average absolute error was 14.91cm, which met the practical application requirements in large-load towing operations.