Abstract:Aiming at solving the problems of poor control accuracy, deficient anti-disturbance ability, and weak stability in agricultural drive motor, a sliding mode variable structure control strategy based on variable speed approaching rate was proposed. The motor control accuracy and stability in the motor control process were improved through the sliding mode variable structure control. In view of the problems of slow approaching speed, broad chattering fluctuation, and low control accuracy at the constant speed approaching rate in the convergence process of traditional sliding mode variable structure control, the variable speed approaching rate was studied for optimization and improvement. At the variable speed approaching rate, the problem of approach speed/buffeting fluctuation balance was effectively realized through introducing the system norm in the motor control process, which improved the control efficiency of the agricultural drive motor and ensures stability. In addition, because of the internal mechanical parameters and external load disturbance, which can have a detective influence on the speed control performance of the agricultural motor, an anti-disturbance method based on an extended sliding mode observer was designed to observe and compensate the internal parameters and external load disturbance in the motor control process. Through Matlab/Simulink simulation test and motor platform experiment, it can be proved that the control strategy proposed can complete the starting speed response within 0.1s in the starting process without overshoot, which effectively improved the control accuracy and response speed of agricultural drive motor. The designed disturbance observer improved its anti-interference ability and robustness. When the external load disturbance of 10N·m/-10N·m was received, the speed error can be eliminated within 5%, which effectively improved the stability and safety of the agricultural motor in the operation process.