Composite SOSM controller for path tracking control of agricultural tractors subject to wheel slip

• Published in: ISA transactions Vol. 130; pp. 389 - 398
• Main Authors: Ding, Chen, Ding, Shihong, Wei, Xinhua, Mei, Keqi
• Format: Journal Article
• Language: English
• Published: United States Elsevier Ltd 01.11.2022
• Subjects: Agricultural tractors; Disturbance observer; Path tracking; Precision agriculture; Sliding mode; Precision agriculture; Disturbance observer; Path tracking; Agricultural tractors; Sliding mode
• ISSN: 0019-0578; 1879-2022; 1879-2022
• DOI: 10.1016/j.isatra.2022.03.019

In the work, the path tracking control methods are developed for autonomous agricultural tractors subject to wheel slip constraints by using second-order sliding mode (SOSM) and finite-time disturbance observer (FDOB) techniques. First of all, the path tracking error dynamics derived from the kinematic model is given and applied to controller design. In order to deal with the inevitable chattering problem existing in the conventional first-order sliding mode (FOSM) controller, a SOSM controller is constructed by regarding the controller derivative as the new control law, which means that the practical control law can be seen as an integration of the SOSM controller. Through a combination of the FDOB and the designed SOSM controller, the composite path tracking controller is further constructed to avoid high control gains in the designed SOSM controller. The strict Lyapunov stability analysis is carried out to ensure that the sliding variable can be finite-time stabilized to the origin under the proposed control algorithms. Finally, the comparative simulation results confirm that the developed guidance laws can achieve good tracking performance and strong robustness even in the presence of slipping effects. •The second-order sliding mode (SOSM) controller is designed to solve the path tracking control problem of agricultural tractors.•The composite control method is proposed to avoid high gains in the designed SOSM controller.•The slipping effects and unknown external disturbances are simultaneously considered in the controller design.