Sliding Mode Variable Structure Based Path Following Control of Agricultural Robots with Differential Drive

Abstract

It is difficult to establish the precise mathematical model of agricultural wheeled robots with differential drive for path tracking control, due to characteristics of nonlinear, strong coupling and multivariable. Here, path tracking control is studied for agricultural wheeled robot with differential drive based on sliding mode variable structure. Firstly, the motion model of agricultural wheeled robots with differential drive is established and control goal is determined for path tracking. Then, sliding mode variable structure is applied to design the controller. Finally, tracking simulations were conducted with circle and sine curves to verify the controller’s performance, and further real tests were carried out on a circle with a radius of 7 m at a test field. The simulations show that the robot can asymptotically stabilize the given trajectory when there is external interference, and the real tests indicate a good tracking performance with a maximum tracking of 0.21 m. The effectiveness of sliding mode controller is verified for trajectory tracking control of agricultural wheeled robots with differential drive.