Research On Course Motion Control Of Underwater High Speed Vehicle

Research on longitudinal control of supercavity vehicle is a developed area, however, theheading control technique is still in initial stage, few related literatures can be found.The difficulty of the heading control of supercavity is that, firstly, the stress environmentof the vehicle is complicated. The vehicle produces cavity during navigation to reduce theresistance and raise the speed. However, the changing of the running state could haveinfluence on the morphology of the cavity, or even break them up andl affect the stress of thetail which is not helpful to the stability control. Secondly, the coupling among pitch motion,roll motion and course motion are too high to use conventional method to control and analyzeit. In this paper, the dynamic model of underwater vehicle is transformed into linear model,and two sorts of controller are designed and simulated. The summary is as follows:The supercavity theory is studied based on related literatures, including the productionconditions, maintenance method and deformation theory of supercavity, in addition, theempirical formula of size and shape is figured out. The configuration scheme, that is, thecoordinated control between tail rudder and double freedom cavitator is proposed. The furthermechanical analysis of supercavity vehicle is done, and the formula for tail rudder andcavitator is given. The non-linear dynamic model of supercavity vehicle is figured out byanalyzing the vector effect among tail planning force, gravity and thrust.Taking the processing method of dynamic model in longitudinal control as reference,based on small perturbation theory, the equilibrium point is appropriately choose to overcomethe roll motion effect. Taking the coupling between pitch motion and course motion as smallperturbation, the state space expression of the coupling dynamic model is obtained. Therelated characteristics of the system are analyzed.LQR controller and mixed sensitivity double-loop robust controller are designed throughanalyzing the linear dynamic model of supercavity vehicle in course motion. The system issimulated under both controllers, the result shows that, the cavitator plays a key role in coursemotion, and the effect of tail rubber is not significant. Therefore, in engineering practice,thrust vector method is suggested rather than tail rubber to control the suptercavity vehicle.