A modified LOS path following control for underactuated AUVs in the presence of ocean currents

In order to solve the curved-path path following problem for underactuated autonomous underwater vehicle (AUV) in the presence of ocean currents, this paper proposes a modified Line-of-Sight (LOS) path following control strategy. The guidance law is derived based on a new path-following error kinematic model with relative velocities of the vehicle in the Serret-Frenet frame, which makes the AUV produce a variable sideslip angle to compensate for the drift force. Dynamic controllers built on Lyapunov theory and backstepping technique stabilize the yaw and relative surge velocity simultaneously. Stability analysis shows that the stronger stability property of uniform local exponential stability (ULES) is achieved for the whole control system. In the end, simulations are carried out to validate the effectiveness of the proposed control method.