Sliding Mode Nonlinear Observer Design for Underwater Vehicle Control System

The ocean current and cable will affect the ROV(remotely operated vehicle) when ROV is working under the sea. Current velocity and umbilical cable disturbing are hard to measure by sensors, which has to be estimated by observer. In order to improve the precision of observer, we present reasonable models for ocean current and umbilical cable disturbance, and design a sliding mode observer which has the same robustness as sliding mode controller. An upper bound of estimation error is derived by using Lyapunov stability criterion. Performance of the observer is verified using numerical simulation.Algorithm is very easy to complie,could meet the engineering needs.