Research On Control Of Ventilated Supercavitating Vehicles Based On Water Tunnel Experiment

As the high speed vehicles in a cruise phase, the viscous resistance on the surface will grow rapidly with the speed increases, which is the main factor that limits the speed. In recent years, the rapidly development of supercavitation drag reduction technology has proven to be a good solution for this problem. Supercavities can be devided into two types, one is nature supercavity and the other is ventilation supercavity. It can not form a complete nature vacuoles when the vehicles is at a low speed relative to the water flow. So in this water tunnel experiments, we will mainly study for the characteristics of ventilation supercavity. Then we will design a backstepping LPV controller and make a simulation to verify. The main contents are as follows:Firstly, a body coordinate system is established with its origin fixed at the nose of the vehicle body. Under this frame forces and respective moments, including the gravity, the cavitator force, the planning force and the moments corresponding to the force are analysed.Based on the previous forces and moments analysis, nonlinear motion equations and dynamical equations are established for the longitudinal motion of a supercavitating vehicle in an ideal case.Secondly, the gravity water tunnel experimental platform is constructed, the vehicles model and controller programming are completed. Which include supercavitation vehicles model manufacturing,servo control system installation and debugging,totaly construction of hardware devices, such as pneumatic compression, flow and pressure testing. Upper computer programming running of the servo drives and controller. Which can Pull supercavitation vehicles moving stably according to the given pulse command. And high speed camera will record the whole change process of vacuoles morphology.Thirdly, we will make improvements against the originally theoretical model according to the experimental data of water tunnel experiments. Then design a controller for this model.By modeling the planing force as the product of a time-varying parameter and the state variable,the original system is translated to an LPV model whose system matrix depends affinely on the time-varying parameter. We consider combining backstepping control algorithm of LPV and they will be given in LMI form, which can be easily sovled.Finally, make a simulation verification in Matlab environment. Then make a futher discussions combining with the simulation and experimental results.