| At present,unmanned farm has been paid more and more attention at home and abroad.The research on unmanned operation of tractor operating units provides technical support for the development of unmanned farm.In order to improve the intelligent level of unmanned operation of tractor operating units and realize the joint control of unmanned operation of tractor operating units,a cooperative control system for unmanned operation of tractor operating units was designed.According to the requirements of unmanned operation,the unmanned operation cooperative control scheme is formulated,which is mainly divided into planning layer,decision-making layer and execution layer.The seeder unit is taken as the research object,the planning layer,the decision-making layer and the executive layer are designed respectively,and the unmanned operation test platform of the tractor operating unit is built,and the collaborative control system is verified through simulation analysis and field experiment.The main research contents are as follows:(1)planning combined with agronomic requirements and kinematics characteristic,tractor unit operation path can be divided into straight line operation area and resident area of turning,based on the mathematical model of the line segment operation path planning method for units and curve section of path planning,is obtained by "line escapement" method to integrate the global operation path.In order to satisfy the path tracking of the working area and the turning curve area of the straight line section,an adaptive preview path tracking control algorithm is proposed to improve the path tracking control precision.(2)Conducted hardware wire control modification and control principle analysis for the steering system,throttle system,clutch system,braking system and lifting system of the operating unit,designed the controller and unit circuit,and designed the CAN bus according to the requirements of the vehicle communication.According to the operational requirements of seeding agriculture,the cooperative control strategy of unmanned seeding operation of the operating unit was formulated.The actions of unmanned seeding operation of the operating unit were analyzed,and the cooperative control logic of unmanned seeding operation of the operating unit was obtained by judging the position of mark points in the path.(3)Unmanned operation simulation and field test were carried out,and the simulation results verified the feasibility of the cooperative control system for unmanned operation of tractor operating units.Field tests show that the steering,throttle,clutch,brake and tool lifting of tractor units work together in strict accordance with the established control strategy.In the test process,the average error of steering control is 0.45°,the mean of lateral error of straight line section is 0.035 m,and the maximum of lateral error of turning section is 0.28 m.The lifting response time of the machine and tools is 1.2s,and the overshoot of the lifting Angle is less than 1.5°.Unmanned operation cooperative control system meets the requirements of unmanned operation of tractor units and provides technical support for unmanned farm. |
