Simulation and Experimental Research on Speed Control of Electric Threshing Drum in Combine Harvester Based on Fonssmo-Mpc Control Strategy

In response to the issues faced by conventional combine harvesters' threshing drums, such as the difficulty in maintaining stable speed in the face of load fluctuations, resulting in increased entrainment loss, as well as the difficulty in adjusting the speed over a wide range when facing changes in crop varieties and properties, an electric threshing drum (ETD) for combine harvester is proposed in this study. A motor control strategy based on fractional-order non-singular sliding mode observer (FONSSMO) and model predictive control (MPC) is designed to achieve precise speed control of the ETD under load fluctuations and disturbances, and its parameters are optimized by applying genetic algorithm. The simulation results indicate that, the ETD can achieve rapid and accurate speed regulation, and in the presence of torque interference and load transients, the proposed control method can reduce the RMS value of the speed error of the threshing drum by 73.96% and the maximum speed error by 75.10%, significantly improving the robustness of the threshing system. The bench test further proved the effectiveness and feasibility of its control strategy. In addition, the field test results of rice harvest indicate that the combine harvester equipped with the ETD can reduce entrainment loss rate under changes in vehicle speed and load compared with the conventional one. When the vehicle speed is 2m/s, it can reduce entrainment loss by 19.43%, which can effectively improve the efficiency of harvesting.