1998 Volume 60 Issue 2 Pages 89-96
Trajectory control method of implements mounted on autonomous agricultural vehicles which are equipped with four-wheel-steering mechanism have been studied. This method was developed based on the fact that lateral moving speed and yaw angular velocity can be controlled individually in four-wheel-steering vehicles. The required condition for tracking was derived from simplified equations of motion with assumptions which include no tire skidding, steady state motion and a flat and level surface. A method for calculating steering angle which fulfills the tracking condition was also proposed. Simulations of 90 degree turns indicated that while the proposed control method make a mounted implement move on a given path preciously, the required steering angle was strongly dependent on the shape of the paths. After comparing three shapes of paths (square corner, circular arc and clothoid curve), it was concluded that the clothoid path is most suitable among the compared path functions.
