拖拉机机组无人作业协同控制系统设计与试验

Design and Experiment of Unmanned Operation Cooperative Control System for Tractor Operating Unit

为提高拖拉机作业机组无人作业的智能化水平,实现机组横向运动、纵向运动和机具提升作业的协同控制,设计了无人作业协同控制系统。以播种作业机组为研究对象,将拖拉机机组无人作业协同控制系统划分为规划层、决策层和执行层。规划层结合播种农艺要求和机组运动学特性,采用经/纬度坐标规划作业路径,为了同时满足直线作业区域与转向曲线区域的路径跟踪,提出自适应预瞄路径跟踪控制算法。决策层制定了拖拉机机组无人作业联合控制策略,实现拖拉机播种机联合作业精准控制。执行层对拖拉机转向机构、机具提升机构、油门踏板、制动器、离合器等机构进行硬件线控设计。在此基础上,分别开展无人播种作业仿真与田间试验,仿真结果验证了拖拉机播种机组无人作业协同控制系统的可行性。田间试验表明:拖拉机转向器、油门踏板、离合器、制动器、机具提升机构严格根据规划层与决策层制定的控制指令协同动作。试验过程车轮转向平均误差0.45°,直线段横向误差均值为0.035 m,转向段横向误差最大值为0.11 m;机具提升响应时间为1.2 s、机具提升转角超调量小于1.5°;油门踏板、制动器、离合器均根据决策指令完成操纵动作。无人作业协同控制系统满足拖拉机机组无人作业的需求,可为无人农场提供技术支撑。

In order to improve the intelligent level of unmanned operation of tractor operating unit and realize the cooperative control of lateral movement,longitudinal movement and tool lifting operation of tractor operating unit,a cooperative control system for unmanned operation was designed.Taking the seeding operation unit as the research object,the unmanned operation cooperative control system of tractor unit was divided into planning layer,decision layer and execution layer.In combination with the agronomic requirements of seeding and the kinematics characteristics of the tractor operating unit,the planning layer used longitude/latitude coordinates to plan the operation path.In order to meet the path tracking of both the straight line segments operation area and the turning curve area,an adaptive preview path tracking control algorithm was proposed.Decision layer formulated the unmanned operation joint control strategy of tractor operating unit to realize the precise control of tractor-planter joint operation.Execution layer was used for hardware control design to the tractor steering,lifting,throttle,brake,clutch and other mechanisms.On this basis,the unmanned seeding operation simulation and field experiments were carried out respectively,and the simulation results verified the feasibility of the unmanned operation cooperative control system for tractor seeding unit.Field experiments showed that the steering,throttle,clutch,brake and tool lifting of the tractor worked together strictly according to the control instructions made by the planning layer and the decision layer.In the experiment process,the average error of steering control was 0.45°,the mean of lateral error of straight line segments was 0.035 m,and the maximum of lateral error of turning section was 0.11 m.The lifting response time was 1.2 s,and the overshoot of lifting angle was less than 1.5°.Throttle,brake and clutch were all operated according to the decision instruction.Unmanned operation cooperative control system met the requirement of unmanned operation of tractor unit and provided technical support for unmanned farm.