Robust Adaptive Asymptotic Control for Heave Motion of Surface Effect Ships

In this paper, a roubst adaptive controller is developed for damping heave motion of surface effect ships in the presence of unknown time-varying environmental disturbance. The disturbance is modeled as the output of a linear exosystem. Further, based on this exosystem, we represent the disturbance as the output of a linear model of canonical form by a linear regression model. The regressor, which is the state vector of such linear regression model, is observed by constructing a disturbance observer. Therefore, the disturbance compensation control for surface effect ships is reduced to a parameter adaptive problem. By employing adaptive backstepping approach, we realize the disturbance compensation and the control design simultaneously. Unlike some existing control scheme for heave motion of surface effect ships, the proposed controller can regulate the heave motion position asymptotically while guaranteeing the uniform ultimate boundedness of all signals in heave motion closed-loop control system. Finally, simulations on a Norway Navy's surface effect ship are carried out to demonstrate the effectiveness of the proposed heave motion robust adaptive controller.