Visual Image Based Dynamical Positioning Using Control Laws with Multipurpose Structure

Dynamic positioning systems are widely used now to support marine operations of various types. In this paper the problem of dynamic positioning using nonlinear visual feedback control with special multipurpose structure is considered. The control objective is to stabilize the difference between given and actual position of the observed visual points in the image plane. The additional complexity of the problem is determined by presence of external disturbances, such as waves and wind. In this paper joint mathematical model of a ship and screen image dynamic is obtained. Using special unified multipurpose structure of control law, mentioned problem is decoupled into particular separated problems. The resulting nonlinear controller provides asymptotic stability and desirable dynamic properties of the closed-loop system regarding external disturbances