Design And Experiment Of Autonomous Navigation Operation Control System For Rape Direct Seeding Unit

With the improvement of agricultural machinery intelligence level,unmanned farm becomes an important development direction of future digital agricultural production mode,and unmanned agricultural machinery operation is a key technology for its development.Aiming at the problems of high labor intensity and low operational efficiency of manual driving operation in rape sowing process in the rice and oil rotation area in the middle reaches of Yangtze River,this paper explores the key technology of unmanned operation of rape direct seeding unit,based on the requirements of rape field sowing and unmanned operation,takes rape direct seeding unit as the test platform,designs the autonomous navigation operation control system of rape direct seeding unit,carries out the simulation and field test to verify the functionality and stability,the main research contents are as follows.(1)The autonomous navigation operation control system of the oilseed rape direct seeding unit was built.The hardware platform of the system mainly consists of a fully electronically controlled tractor,rape direct seeding machine,information acquisition module,actuator and control module,with the industrial control computer as the main controller,and the position information of rape direct seeding unit is acquired through Beidou RTK positioning system and angle sensor.And the live broadcast unit was modified automatically,and the electric steering wheel was used to control the steering of the live broadcast unit,and the CAN bus-based walking and operation control module was built.(2)Designed the rape direct seeding unit set row operation path and navigation operation control strategy.Based on the boundary information of the convex polygon field,the operation characteristics and optimal operation direction of the live rape unit,the global set operation path was generated by combining the bow-shaped field head change method,and the set path planning algorithm simulation test was carried out.The navigation operation behavior of the direct seeding unit was divided into deviation,speed,suspension and PTO control,and the control strategy of unmanned seeding operation of the direct seeding unit was formulated according to the deviation and set row path information.(3)The pure tracking control method based on fuzzy rules and PD steering control algorithm were designed for the soil sticky weight in rice board field and the row requirement of oilseed rape sowing.In order to adapt to the complex steering control in the sowing process,the concavity of the field surface and the navigation control under different speeds,fuzzy rules were formulated to output the forward-looking distance to the pure tracking control algorithm.Simulation tests proved that the method reduced the overshoot by 5.34% and the stabilization time by 4.1s compared with the conventional pure tracking control method,which effectively improved the robustness and convergence speed of the algorithm.(4)Experiments on the autonomous navigation system of rape direct seeding units were carried out.The test results show that the maximum lateral deviation of set-row tracking on concrete road is less than 3.93 cm and the average absolute lateral deviation is less than 1.78 cm in the speed range [0.8m/s,1.8m/s];the maximum deviation of straight-line tracking in rice board field is 5.73 cm and the average absolute lateral deviation is 1.55 cm.The average absolute lateral deviation of the set-row sowing path is less than 7.43 cm.The test platform can complete the sowing operation independently according to the planned set-row operation path,and the navigation operation control effect is stable.