Observer based finite-time switched controller of an underactuated surface vessel

In this work, a switched control law is proposed to make the desired set point of an underactuated surface vessel finite-time stabilization. The control law is separated into three actions. Each action makes the system have a double integrator subsystem and we use a finite-time controller to achieve a certain objective. In order to overcome the difficulties of measuring the linear and angular velocities of underactuated surface vessels, in the condition that only the position and orientation are measurable, we present second-order sliding-mode observers of the velocity u, v, and r for the vessels. Simulation results show that the control law is effective.