Dynamic Positioning of Dredgers Based on Disturbances Compensating

In order to deal with the control difficulties of the dredger's dynamic positioning system under large disturbances caused by dredging operation, a disturbances compensating dynamic surface control method is proposed to be used in the dredger's dynamic positioning system. Disturbances can be measured and compensated by the adding forces sensors. The proposed robust controller guarantees the semi-globally asymptotical stability of the closed-loop system, and output asymptotic track to desired trajectory. The addition of low pass filters in backstepping design process allows the dynamic surface control technique to be implemented without differentiating any model nonlinearities, which could simplify the design significantly. This scheme is verified by the comprehensive simulation results in typical operation scenarios. The simulation results show that the proposed controller has desired position tracking transient performance and robustness to the disturbances caused by dredging forces.