Disturbance compensated adaptive backstepping control for an unmanned seaplane

A disturbance compensated adaptive backstepping controller is presented for a class of nonlinear systems with external disturbances. We develop a disturbance observer, with which the problem of disturbance compensation can be transformed into an adaptive control problem. Command filtered adaptive backstepping method is then used to design the control law to track the desired trajectory. In order to analyze the property of the controller, the overall close-loop error system is built. Using the Lyapunov approach, we prove that the proposed controller provides the uniformly asymptotic stability for the considered system and achieves perfect disturbance compensation. Finally, the developed method is applied to an unmanned seaplane system in the presence of large external disturbances. Simulation results show that the controller has good performance for the unmanned seaplane in different wave conditions.