An actuator failure tolerant robust control approach for an underwater Remotely Operated Vehicle

This paper proposes an actuator failure tolerant robust control scheme for underwater Remotely Operated Vehicles (ROVs). A reduced order observer has been introduced first, for estimating the ROV velocities. In order to solve the control problem for the ROV positions, a sliding mode control law has been developed using the available position measurements and the velocity estimates provided by the observer. A thruster failure is shown to be detectable simply checking the presence of any deviation of the observed sliding surfaces. Moreover, an isolation policy for the failed thruster is proposed. Finally, control reconfiguration is performed exploiting the inherent redundancy of actuators. An extensive simulation study has been performed, supporting the effectiveness of the proposed approach.