Diving autopilot design for underwater vehicles using multi-objective control synthesis

This paper presents the mathematical modeling, guidance and robust control synthesis of a highly maneuverable submersible vehicle (or underwater vehicle) when performing st specific mission at shallow submergence conditions. First, the vertical plane motions (heave and pitch) of the vehicle are modeled by a set of maneuvering equations. After model simplification, a state space model is compactly obtained. Then a state-feedback controller is proposed for the accurate depth-keeping and pitch motion controls of the vehicle. The control actions to the generalized plant can be provided by the mixed H-2/H-infinity optimal synthesis as well as closed-loop pole constraint with LMIs. The feasibility of the guidance and control approach is verified with direct numerical simulations. The proposed approach ensures reasonable depth-keeping and minimal pitch motions, even under a given uncertainty condition.