ADS Adaptive Backstepping Sliding Mode Depth Controller with Time-Varying Disturbance Observer

The Atmospheric Diving Suit (ADS) depth movement control have some problems caused by model uncertainty, unknown disturbance. To address these problems, this paper introduces a sliding mode backstepping and time-varying observer disturbance observer with adaptive law. The time-varying disturbance observer can track disturbance on ADS move, and the adaptive sliding mode backstepping controller controls the vertical movement of ADS, thus the tracking error can be controlled to approximately zero. In the paper, to test the controller's stability and proving the controller can track the error caused by model uncertainty and disturbance, the Lyapunov method is used. Simulation proves the controller's performance in overcoming uncertainties and disturbances with good robustness, stability and error-tracking convergence.