Research On Robust Variable Gain Control For Underwater Hign Speed Vehicle Based On LPV

It is of great significance for speed increasing of vehicle underwater to reduce resistance sharply and effectively.In Comparing with traditional means such as the increase of thrust or the optimizing of structure to achieve the high speed of vehicle,the supercavitation technology is drawing the attention of a large number of countries and regions,which can make the most even entire surface of the vehicle enclosed to achieve the super high speed easily through a sharp decrease of resistance underwater.It is vital to build the precise modle and design the effective controller in the process of the supervehicle's designing.What should be pointed out is that,the sharp decrease and constant variation of the effective area between vehicle and water brings great difficulties to the force and its moment analysis acurately.On the other hand,the super high speed and the complex environment make buliding the accurate modle and designing the effective controller of the supervehicle face serious challenges,what's more,which contains great theoretical and practical significance.Thus,the mathematical model of the vertical vehicle plane can be given through the analysis of forces and moments in this paper,based which the control methods are designed and the similation verification for the closed-loop system is given in the last.Firstly,the mathematical model of vertical vehicle plane is bulided.The body coordinate system of the vehicle is established,through which the forces and their moments caused by cavitation,stern rudder,gravityand sliding between water and cehicle surforce are analyzed.The important nonlinear sliding force caused between the vehicle surforce and water is given detailed analysis,thus,the noninear mathematical model of vertical vehicle plane is achieved.Secondly,the variable gain state feedback robust controller based on LPV is designed.As the nonlinear sliding force has a deep relationship with vertical speed in the system,the LPV description of the system can be gotten if we transform the nonlinear sliding force properly and rewrite the benchmark model.The state feedback controller can be achieved through the building and resolving of the LMIs.In the end,the effect of the controller and the robustness againest interference outside should be verified through similation.Thirdly,the variable gain output feedback robust controller based on LPV is designed.We can get the polytopic augmented description of the system through the introduction of weignted functions based on LPV description,and then the output feedback controller can be achieved through the building and resolving of the LMIs.Simulations are also conducted to evaluate the effectiveness and robustness of the controller designed.At last,the variable gain slack variable robust controller based on LPV is designed.In the process of controller designing,the Lyapunov function and the system matrix can be decoupled with slack variable introduced through the proper tranformtion of LMI,by which we can apply different Lyapunov functions on the different polytopic points,and then the conservative brought by using a polic Lyapunov function in the scope of variable parameters.Simulations are conducted to evaluate its robustness under the situation that the system faces noise disturbance,and then compare the control performance of the resulting controller and that of the previous one.