Tractor-implement dynamic trajectory model for automated navigation applications

The determination of dynamic response of tractor trajectory to a steering action is essential for achieving accurate guidance of agricultural tractors. This research investigated the dynamic response of a tractor-implement system via a dynamic model of the system. To provide sufficient details without loss of generality, this model, implemented in the MATLAB® environment, consists of a tractor bicycle model and a pulling-wheel implement model based on a John Deere 7700 tractor and a pulling cultivator. The simulation results obtained from this model was validated in field tests. The cornering stiffness of the wheels was found to be the critical system parameter in this model. The values of the cornering stiffness were determined by conducting a series of circling tests at different speeds on the testing fields. Field validation test results indicated that the developed tractor system dynamic trajectory model could accurately estimate the trajectories of a tractor-implement system at various traveling speeds.