Control of a Torpedo-Shaped AUV with Partial Actuator Failure

In this paper, we present a robust super-twisting sliding mode controller in the presence of partial actuator failure for a coupled nonlinear 6-degree of freedom torpedo-shaped autonomous underwater vehicle. We develop the appropriate sliding surfaces and control laws to effectively regulate the vehicle's speed, depth, and steering motion. The system's stability is proven, and the appropriate gain is determined using the Lyapunov approach. Furthermore, range analysis is performed to determine an allowable range for the partial actuator failure cases corresponding to the thruster, rudder, and stern actuators. The proposed control laws are validated using simulation, and results are presented.