田间管理机路径跟踪系统设计及试验

Design and experiment of path tracking system for field management machine

为了解决田间管理机前轮转向时内轮差造成的农作物损失问题,本研究提出了一种基于四轮转向田间管理机的路径跟踪算法。以3WPZ-750田间管理机样机为研究对象,设计了一套路径跟踪控制系统,阐述了该田间管理机转向支腿机械结构设计和自动液压转向系统原理,概述了在原有控制系统基础上路径跟踪上位机控制系统的技术路线;基于四轮转向模型,进行纯追踪算法车轮转向角控制研究;基于微软集成开发环境(visual studio)编写了路径跟踪控制界面;并分别于水泥路面和南方水田环境下进行直线路径跟踪试验与曲线路径跟踪试验。结果表明:在0.5 m/s的车速下,田间管理机在水泥路面上的路径跟踪误差均值为6.92 cm,标准差为4.84 cm;定曲率曲线路径跟踪误差均值为12.49 cm,标准差为9.16 cm。在0.2 m/s车速下,在南方水田环境下的路径跟踪误差均值为2.25 cm,标准差为1.35 cm;定曲率曲线路径跟踪误差均值为8.72 cm,标准差为5.59 cm。说明本研究设计的路径跟踪系统能够满足田间管理机行驶以及田间作业需要,为农业机械自动驾驶提供了一定依据。

In order to solve the problem of crop loss caused by the internal wheel difference when the front wheels of the field management machine were turned,this study proposed a path tracking algorithm based on the four-wheel steering field management machine.Taking the 3 WPZ-750 field management machine as the research object,a set of path tracking control system was designed.First,the mechanical structure design of the research subject’s steering outriggers and the principle of the automatic steering hydraulic system were explained.Second,the technical route of the path tracking host computer control system based on the original control system was outlined.Then,based on the four-wheel steering model,a pure tracking algorithm was used for wheel steering angle control research.Finally,the path tracking control interface was written based on Microsoft integrated development environment(visual studio).Through its experimental platform,the straight path tracking and curved path tracking experiments were carried out on the cement pavement and the southern paddy field environment,respectively.The results showed that at the speed of 0.5 m/s,the field management machine had a path tracking error of 6.92 cm on the cement pavement,and its standard deviation was 4.84 cm;while the mean value of the path tracking error of the fixed curvature curve was 12.49 cm,and its standard deviation was 9.16 cm.At the speed of 0.2 m/s,on the southern paddy field,the mean value of the path tracking error was 2.25 cm,and its standard deviation was 1.35 cm;while the mean tracking error of the fixed curvature curve was 8.72 cm,and its standard deviation was 5.59 cm.The above results indicate that the path tracking algorithm proposed in this study can meet the needs of field management machines and field operations,and provide a basis for automatic driving of agricultural machinery.