A trajectory planning and tracking control approach for obstacle avoidance of wheeled inverted pendulum vehicles

This paper investigates a trajectory planning and tracking control scheme to implement the autonomous obstacle avoidance for wheeled inverted pendulum (WIP) vehicles, which enable the mobile platform to avoid obstacles rapidly and stabilise the vehicle body simultaneously. In the first place, an obstacle avoidance trajectory planning method suitable for the WIP vehicle is proposed, which, in particular, is capable of planning an obstacle avoidance trajectory with the merits of continuous curvature and approximately zero longitudinal acceleration in vehicle body-fixed frame system. Then, aiming the feature of the each subsystem, a nonsingular terminal sliding mode control and a nested saturation approach are employed to construct the trajectory tracking algorithm for fully actuated steering subsystem and underactuated longitudinal subsystem of the WIP vehicle, respectively. Besides, the closed-loop system's stability and asymptotical convergence of tracking error are proven in the sense of Lyapunov stability theory. In the end, numerical simulations are performed to demonstrate the feasibility and effectiveness of the proposed scheme for obstacle avoidance of WIP vehicles.