عنوان مقاله [English]
In this study, a three wheel dynamic model refer to a field tractor with an implement was developed to control the tractor in the field accurately. Main difference between a tractor and in-road vehicles is implements connected to the tractor. These implements exert lateral and draft force to the tractor. In order to investigate these kinds of forces, behavior of implements was simulated like a tire. The study was supposed that side slip angle, steering angle and traction of left wheels of tractor are as same as right wheels. In addition a torque was made by draft force moved to the center of gravity of implement. So six wheels traditional model was simplified to three wheels model. The model was simulated by MATLAB software. Results showed that the lateral force and the draft force of implements had effect on the yaw rate and the side slip angle. In addition, controllability of the model was surveyed and results showed that the model have capability of predicting different states of motion in a finite interval of time.