Fixed-time integral sliding mode tracking control of a wheeled mobile robot

This paper presents a fixed-time integral sliding mode control scheme for a nonholonomic wheeled mobile robot (WMR). To achieve the trajectory tracking mission, the dynamic model of a WMR is first transformed into a second-order attitude subsystem and a third-order position subsystem. Two novel continuous fixed-time disturbance observers are proposed to estimate the external disturbances of the two subsystems, respectively. Then, trajectory tracking controllers are designed for two subsystems by utilizing the reconstructed information obtained from the disturbance observers. Additionally, an auxiliary variable that incorporates the Gaussian error function is introduced to address the chattering problem of the control system. Finally, the proposed control scheme is validated by a wheeled mobile robotic experimental platform.