Terminal sliding mode control of mobile wheeled inverted pendulum

The mobile wheeled inverted pendulum is widely used in many robotic applications and also paid attention by theorists due to its essentially unstable. The equilibrium control and velocity control of a mobile wheeled inverted pendulum are discussed in this paper. Based on the three-dimensional (3D) dynamic model of this underactuated system running on the flat ground derived by Lagrange's motion equation, a terminal sliding mode control (TSMC) is proposed to ensure the underactuated system can be self-balanced and variables converge to desired states. By using the proposed controller, the system can stay at the equilibrium or track a given yaw angle. Numerical simulations are provided to verify and illustrate the effectiveness of the proposed model and controllers.