Robust Adaptive Path Tracking Control of Agricultural Machines Based on Cascaded Control Strategy

Yaw rate dynamics of agricultural machines will change under the influence of implement loads and external disturbances, and thus the path tracking performance of position error-based control methods deteriorates. For this reason, a robust adaptive path tracking control method based on cascaded control strategy is proposed. By this method, the path tracking control task is decomposed into two cascaded control tasks which are the lateral position control task and the yaw rate control task. In the former task, the desired yaw rate of the agricultural machine is determined by utilizing fuzzy adaptive pure pursuit model according to the lateral position error and the heading error. In the latter one, a robust adaptive control method is developed to guarantee that yaw rate has the desired response performance even if the agricultural machine suffers from the implement load variations and the external disturbances. The effectiveness and the superiority of the proposed method are verified by a series of simulation experiments and actual agricultural machine experiments.