Adaptive Sliding Mode Control for Trajectory Tracking in Four-Wheeled Mobile Robots Under Uncertainties and External Disturbances

In this paper, we propose an adaptive sliding mode control (SMC) design technique to track the desired trajectory of the skid-steering mobile robots in the presence of model uncertainties and perturbations. To enhance the stability of the robot and ensure accurate trajectory tracking, adaptive rules have been employed to estimate the upper bound of perturbations. This estimation, in turn, serves to stabilize the robot and guarantee the desired trajectory. Moreover, we analyze and calculate the convergence time of the sliding surface, ensuring its convergence within finite time. Additionally, efforts have been made to minimize the chattering phenomenon by smoothing the discontinuity of the sliding surface. Simulation results validate the efficacy of the proposed controller, demonstrating its ability to deliver acceptable performance in diverse scenarios.