Disturbance Observer-Based Double-Loop Sliding-Mode Control for Trajectory Tracking of Work-Class ROVs

The open-frame structure of work-class ROVs results in significant model uncertainties, and its motion is strongly disturbed by the umbilical cable. To address these problems, this article developed a nonlinear disturbance observer-based super-twisting double-loop sliding-mode control (NDO-STDSMC) method to achieve trajectory tracking with system uncertainties external disturbances. First, new outer-loop controller novel reaching law designed increase convergence rate compared existing (DSMC). Second, an inner-loop that combines advantages scheme proposed guarantee error converges zero finite time. Then, observer estimate compensate for stability overall proven Lyapunov approach. Finally, comprehensive simulation studies on are provided demonstrate efficiency NDO-STDSMC superiority over DSMC STDSMC methods.