| Intelligent agricultural equipment has been listed as one of the development fields in the made in China 2025 plan,and unmanned driving technology is a hot issue in the research of intelligent agricultural equipment.The driverless technology of transplanter can improve work efficiency,effectively avoid missed work and heavy work,and reduce the labor intensity of operators,but the relatively complex working conditions,high cost and accuracy requirements restrict its wide range of application.In order to solve the problems of high precision and low intelligence of transplanter,this paper refits the transplanter automatically,and studies the global coverage path planning and path tracking control algorithm of driverless technology.The main research contents are as follows:(1)Set up the hardware platform of the unmanned transplanter.In order to solve the problem of low intelligence of traditional transplanter,Jing guan pz60 transplanter was used as the experimental platform to refit the transplanter automatically by installing electric steering wheel,GPS receiver,angle sensor,etc.(2)Static global coverage path planning for the target parcel.A path planning method is proposed to maximize the proportion of effective job paths.Firstly,the boundary coordinates of the target plot are obtained by GPS instrument,and the plot boundary coordinates are transformed into plane coordinates by Gauss projection;secondly,the turning form and operation direction of the transplanter are determined,the interior area of the plot is divided,and the path planning of the straight line section and the turning section is completed;finally,the control sequence which is convenient for the identification of the transplanter is generated,and the control sequence is imported into the upper computer software In order to complete the path planning system.(3)Aiming at the problem of path tracking of the transplanter driverless,a combined control algorithm is proposed.Firstly,the requirements of path tracking in straight-line segment are analyzed.According to the characteristics of fuzzy control and pure tracking model,an improved pure tracking model is designed.Based on the fuzzy control principle,the controller is designed.The input speed and lateral deviation,and the forward-looking distance are output,so as to dynamically adjust the pure tracking model.Secondly,aiming at the problem of path tracking in turning segment,a fuzzy PID based pure tracking model is proposed According to the principle of fuzzy control,the PID control parameters can be adjusted on line by inputting the lateral deviation and deviation change rate.The simulation results of the combined control algorithm show that the maximum lateral deviation is 6.8cm,the average value is 2.7cm,and it oscillates greatly at the turning,and the overall tracking effect is good.(4)The control system of transplanter driverless was tested and verified.The self-driving test was carried out on the flat cement road and paddy field with the modified well closed transplanter as the test platform.Test results: when the transplanter is running on the straight section of the cement road,the maximum value of the transverse deviation is 4.9cm,the average value is 2.6cm;when the transplanter is running on the straight section of the paddy field,the maximum value of the transverse deviation is 6.4cm,the average value is 4.3cm.It is verified that the designed driverless control system can track the predefined path accurately. |
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