Optimal steering stabilization of an autonomous underwater vehicle using nonlinear output feedback control

This research addresses the AUV's Optimal stabilization problem in steering plane. This control problem is formulated considering an AUV model with six Degree of Freedom. This model is then decoupled into steering plane. Feedback linearizable Normal form of steering plane model of AUV is then derived. An optimal nonlinear controller is proposed based on inverse optimal methodology with Control Lyapunov Function existence and use of minor varied Sontag's formula. The nonlinear optimal control is then extended to High Gain Observer (HGO) based nonlinear output feedback control. Lyapunov stability analysis and graphical results are included to validate the designed controller performance.