L2-Gain-Based Practical Stabilization of an Underactuated Surface Vessel

To obtain a stabilizer for an underactuated surface vessel with disturbances, L2-gain design is proposed. Surge, sway, and yaw motions are considered in the dynamics of ship. ob-tain robust adaptive controller, diffeomorphism transformation Lyapunov function employed controller design. Two auxiliary controllers introduced equivalent sys-tem after transformation. Different from commonly used disturbance ob-server-based approach, to suppress random uncertain disturbances ship dynamics. evaluate performance suppressing two error sig-nals defined which variables be stabilized incorporated. Both time-invariant dis-continuous continuous feedback laws proposed control system. Stability analysis simulation results demonstrate validity A comparison sliding mode performed, prove advantage terms faster convergence rate chattering avoidance.