Research on Path Tracking of Rice Direct Seeder Based on Improved Sliding Mode Control
In order to improve the accuracy and stability of path tracking during automatic operation of rice direct seeder,a sliding mode path tracking control method based on a new nonlinear sliding mode surface and an improved fast variable power reaching law is proposed.Firstly,the path tracking kinematics model of the direct seeding machine in the Frenet coordinate system is established.Then,in order to ensure the global convergence of the lateral deviation and the heading deviation in the path tracking process,the hyperbolic tangent function is used to design the sliding surface.Finally,a vari-able exponential power term is designed based on the fast power approach rate,which improves the system reaching speed and effectively suppresses chattering.The model is built on Simulink for simulation.Compared with the sliding mode con-trol methods based on fast power reaching law and exponential reaching law,the tracking error convergence time of the im-proved sliding mode control method in this paper is the shortest without chattering.When the direct seeding machine uses the algorithm in this paper to operate automatically in paddy field at the speed of 0.8 m/s,the mean absolute deviation of lateral deviation and heading deviation is 0.016 9 m and 1.099 9 °,and the standard deviation is 0.021 5 m and 1.4992 °,which improves the accuracy and stability of path tracking and meets the actual operation requirements.
rice direct seederpath trackingsliding mode controlreaching law
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