Development of the automatic navigation system for combine harvester based on GNSS

Abstract

An automatic navigation system was developed to realize automatic driving for combine harvester, including the mechanical design, control method and software design. First of all, for the harvester modified with the automatic navigation system, a dynamic calibration method of the rear wheel center position was proposed. The control part included the navigation controller and the steering controller. A variable universe fuzzy controller was designed to the navigation controller, which used fuzzy control to change the fuzzy universe of input and output dynamically, that means, under the condition that the fuzzy rules remain unchanged, the fuzzy universe changes with the change of input, which is an adaptive fuzzy control method and can modify the control strategy in time. To realize the automatic navigation of the harvester, the decision result of the navigation controller based on the variable universe fuzzy control was input into the steering controller, and then the electric steering wheel was controlled to rotate. To test the performance of the designed automatic navigation system, the field experiment was carried out. When the combine harvester was navigating linearly at a speed of 0.8 m/s, the overall root mean square error (RMSE) of the lateral deviation was 5.87 cm. The test results showed that the system was designed could make the combine track the preset path smoothly and stably, and the tracking accuracy was at the centimeter level.