ROV trajectory tracking control based on disturbance observer and combinatorial reaching law of sliding mode

To ensure that underwater remotely operated vehicles have the ability to complete trajectory tracking in the presence of external disturbances and model parameter uncertainties, this paper proposes a double-closed-loop integrative sliding mode ROV tracking control based on the nonlinear expansion state observer. Firstly, to address the issue of oscillatory vibrations in the stable state of the dual closed-loop sliding mode structure, the inner loop control adopts a combinatorial reaching rate that leverages both exponential and variable convergence rates. Secondly, addressing the impact of external disturbances and model parameter uncertainties on the ROV, this paper proposes a novel nonlinear disturbance observer inspired by active disturbance rejection control principles. The stability of the complete closed-loop cascaded system is substantiated. Simulation outcomes demonstrate that the presented scheme significantly enhances the control system's transient response, disturbance rejection capacity, and ability to suppress jitter vibrations within sliding mode control, thereby proving the robustness, viability, and effectiveness of the control strategy outlined herein.