Design and verification of automatic navigation control system for large high clearance self-propelled sprayer

An automatic navigation system aiming at improving the accuracy and efficiency of a large high clearance self-propelled sprayer was developed. First, a navigation hydraulic steering system was designed according to the structural characteristics and operation requirements of the sprayer, and a mathematical model of the system was established to describe the working characteristics of the navigation system. The system includes a navigation control strategy, a pure pursuit path tracking algorithm, and a fuzzy adaptive proportional-integral-derivative control method. To verify the performance of the system, a simulation model was developed using MATLAB/Simulink, and the performance of the control methods were compared. Additionally, an actual vehicle test platform was built based on 3WPG-3000 high clearance self-propelled sprayer independently developed by the research group. The simulation results revealed that under the two-wheel steering mode, the lateral position deviation of the vehicle decreases to 0 m in 11 s, and the heading angle deviation decreases to 0 rad in about 11 s; while under four-wheel steering mode, the lateral position deviation of the vehicle decreases to 0 m in 8 s, and the heading angle deviation decreases to 0 rad in 8 s. The field test results revealed that at the speed of 3 km/h, the sprayer tracked the target path in 5.84 s under the two-wheel steering mode and reached stability, and tracked the target path in 4.08 s under the four-wheel steering mode and reached stability; while at the speed of 5 km/h, the spray tracked the target path in 3.75 s under the four-wheel steering mode and reached stability. Altogether, the results of the simulation and field test verify the stability, accuracy, and practicability of the system.