Research On Close Relative Motion For UUV Based On Model Predictive Control

As human's exploration of the ocean gradually deeply, the applications of UUV in civil and military fields are increasingly widespread. In order to download data and supply energy,UUV is needed to dock after the job is completed. In recent years,further taking into account the hidden and safety factors, the way of UUV recovery mode is gradually changing into autonomous recovery mode from the way of human intervention,so the accuracy of motion control of UUV are more demanding in the recovery process. In this paper, with the background of the recovery of UUV through underwater mother ship piggybacking, the research on close-hydrodynamic interference and the Model Predictive Control algorithm used in the diving motion and tracking motion of UUV in this recovery process are carried out,This article mainly studied from the following points:First, the fixed coordinate system and the hull coordinate system are established, the kinematics equations of UUV are also established combined with the motion characteristics of UUV; The force analysis of UUV is done including hydrodynamic,hydrostatic,actuators and interference, then the six degrees of freedom motion equations are given out binding kinetics knowledge; Some simulation experiments of the basic movement of UUV are designed to verify the accuracy of the established model.Secondly, a brief overview of autonomous recovery mode using motion mother ship piggybacking combined with practical engineering of UUV recovery is given. The program of simulation through computational fluid dynamics software Fluent is designed according to the recovery mode of underwater mother ship piggybacking UUV, then analyze the data and summarize the law of UUV suffered hydrodynamic interference in such recovery mode.Finally UUV model for vertical motion and pitch motion are revised according to the law of hydrodynamic interference, and summarize constraints in the close relative motion of this recovery progress.Thirdly, the predictive model of UUV for diving control is given through vertical model processed; The algorithm of model predictive control which can be optimized online is used taking into account hydrodynamic force in the relative movement in this way of underwater mother ship piggybacking. A controller is designed based on model predictive control with artificial bee colony algorithm, wherein the artificial bee colony optimization algorithm to solve the main problem of the QP; The stability of controller designed above is proved based on Lyapunov stability theory; Finally, the simulation experiments are design to verify the designed controller performance.Finally, the predictive model of UUV for tracking control is given through level model processed; The accuracy of the model may reduce when the continuous nonlinear system is discrete, so a controller of model predictive control is designed based on continuous nonlinear model taking into account this; The stability of the controller designed above is proved by introducing a virtual feedback mechanism combining Lyapunov stability theory; Finally, the simulation experiments are design to verify the designed controller performance.