Longitudinal Motion Control of an AUV Using Disturbance Estimator-Based Sliding Mode Controller

This paper addresses the longitudinal motion control challenges faced by an autonomous underwater vehicle (AUV) operating in a demanding underwater environment characterized by hydrodynamic parameter variations and disturbances. To tackle these challenges, we introduce a disturbance estimator-based sliding mode control (DE-SMC) law specifically designed for controlling the AUV’s longitudinal motion. To ensure smooth control without chattering effects, we have carefully crafted the disturbance estimator (DE) to exhibit exponential convergence to an unknown disturbance. The feedback-switching gain is also designed to converge to the origin exponentially. Comprehensive validation tests are conducted to evaluate the effectiveness and robustness of the proposed DE-SMC law, including scenarios involving parametric uncertainties and underwater disturbances. The simulation results presented in this paper serve as compelling evidence supporting the efficacy of our control law design.