Strong iISS Target Tracking Controller Design for an Unmanned Surface Vehicle with Uncertain Follower Dynamics and Target Dynamics

This paper presents a strong integral input-to-state stable (iISS) controller design for target tracking of an unmanned surface vehicle (USV) with uncertain kinematics due to time-varying ocean current as well as unknown kinetics due to model uncertainties and external ocean disturbances. The target vehicle moves in the sea with an arbitrary velocity which is unavailable to the follower USV. First, the unknown relative dynamics and kinetics are estimated by the RESOs. Next, based on the recovered information through the extended state observers, a saturated target tracking law is constructed. Finally, the cascade target tracking system is analyzed to be strong iISS. The primary characteristics of the presented strong iISS target tracking controller are as follows. First, the developed strong iISS target tracking control method does not need the velocity of target vehicle in advance and the relative LOS distance and angle are required only. Second, the presented strong iISS target tracking control method can obtain the threshold of the cascade system. Simulations confirm the efficacy of the presented strong iISS target tracking control method for an USV with uncertain target kinematics as well as follower dynamics.