Gain self-adjusting single neuron PID control method and experiments for longitudinal relative position of harvester and transport vehicle

To accurately control the longitudinal relative position of a harvester and transport vehicle, such that grain in the harvester can be accurately unloaded into the transport vehicle's granary, this study established a master–slave collaborative harvesting system. Furthermore, this study proposed a calculation method for the longitudinal deviation of two vehicles, analyzed the structure and mathematical model of the hydraulic stepless transmission, identified the proposed stem transfer function of the hydraulic stepless transmission speed, analyzed incremental proportional–integral–derivative (PID), and developed self-adjusting–single-neuron PID control methods. Simulations and field experiments were performed to test the applicability of the proposed system. The experimental results indicated that the maximum overshoot of the longitudinal deviation between the harvester and the transport vehicle did not exceed 0.25 m, the steady-state mean absolute deviation did not exceed 0.08 m, the steady-state maximum deviation did not exceed 0.26 m, and the steady-state standard deviation did not exceed 0.09 m, when the harvester speed was 0.6, 0.8, and 1 m/s. Field-harvesting application experiments showed that the settling time during the alignment process was 13.2 s, and the steady-state maximum deviation was 0.253 m. The grain can be accurately unloaded into the granary of the transport vehicle. These results indicate that the control method and the master–slave collaborative harvesting system proposed in this study can meet the needs of precise collaborative unloading between the harvester and transport vehicle.