Research On UUV Docking On A Mobile Underwater Recovery System

The technology of Unmanned Underwater Vehicle（UUV）has a great development in thepast ten years. UUV can be used for marine resources detection and military missions.To be areal automatic vehicle, it is necessary for UUV to have the ability of independent homing anddocking. There two kinds of underwater recovery platform for UUV to dock，stick platformand moving platform. The moving underwater recovery platform is more flexible and hiddenthan the static one.In this paper，the research is about the trajectory planning and tracing for UUV dockingon a moving piggyback recovery platform. Firstly we design a recovery strategy and theforbidden area of the recovery platform which UUV can no be in. Then study about themathematical model of UUV.Secondly we design a new method to eliminate the chattering of state feedback slidingmode control (SMC) law for the mobile control of an UUV which is nonlinear and suffersfrom unknown disturbances system.To dissipate the well-known chattering of SMC, theswitching manifold is proposed by presetting a Hurwitz matrix which is deducted from thestate feedback matrix. Meanwhile, the best switching surface is achieved by use ofeigenvalues of the Hurwitz matrix. The state feedback control parameters are not only appliedto control the states of UUV but also connected with coefficients of switching surface. Theconvergence of the proposed control law is verified by Lyapunov function and the robustcharacter is validated by the Matlab platform of one UUV model.Thirdly we design two kinds of methods for UUV to plan the recovery trajectory. Thefirst one is dynamic potential field approach. It can solved the solved the problem of localminima in some situation. The second approach is Navigation Function. The NavigationFunction only have a global minima（the target）and does not have the problem of localminima. The results of simulation show that both of the approach can be used for planning theUUV recovery trajectory.