| In order to track the desired front wheel angle accurately and rapidly, a steering system model was established and a steering control algorithm was designed for the agricultural vehicle. In the system, the master node (an on-board computer) communicated with four slave nodes (front wheel angle measure node, speed measure node, steering motor control node, driving speed control mode) by CAN -Bus communication network. According to the relationship between the input and output of the steering system, a second-order model was built. And an optimal PD controller based on the ITAE (integral time absolute error) performance index was designed to enhance steering performance. The tests were discussed when the vehicle was driving on the farmland and the cement road at the speed of 0.3 m/s, 0.5 m/s, 0.7 m/s respectively. Test results showed that the steering system tracked the desired front wheel angle smoothly under the desired input signals (依20毅of the front wheel angle). The adjusting time was within 0.35 s and the steady-state error was less than 0.5. |
