Optimal output feedback disturbance rejection for underactuated autonomous underwater in vertical plane

This paper addresses the motion control problem of underactuated autonomous underwater vehicles (AUV) in vehicle plane affected by disturbances. Firstly, a six degrees-of-freedom AUV model with its body-fixed coordinate system is decoupled, simplified, and linear zed, and the depth control model and the wave model are obtained; Then a optimal output feedback disturbances rejection control law is proposed with a higher mean-square convergence rate, which is derived from a Riccati equation and Sylvester matrix equation according to the quadratic performance indexes. The proposed controller consists of a feedforward disturbance rejection item and an optimal output feedback item. Finally, the controller is applied to the dive plane control of AUV with wave force disturbances, and simulation results are presented to verify the effectiveness of the methods.