Research On Hydrodynamic Performance And Motion Control Of Underwater Vehicle

Autonomous Underwater Vehicle(AUV)is a kind of underwater robot without cable restriction.It has its own power system and intelligent control system to realize autonomous decision and intelligent control.It can replace people to complete high risk and demanding work such as resource detection,water quality monitoring and so on.The application fields are related to the field of marine science,military and economic fields.With the development and progress of the times,people need more abundant marine energy resources.The requirements for the use of AUV are becoming strict,and AUV is developing towards the direction of miniaturization,light and intelligence.When AUV works in the marine environment,the motion is complex,nonlinear and time-varying.The hydrodynamic performance is an important basis for AUV design and is also an indispensable prerequisite for the realization of the AUV motion control.Theoretical calculation,approximate estimation and maneuverability test are the most widely used methods to obtain the hydrodynamic coefficients.Computational Fluid Dynamics(CFD)is developing quickly.Using CFD method to obtain the hydrodynamic coefficients is realized.This method is more convenient and efficient to predict hydrodynamic performance.Numerical simulation results of a standard ellipsoid are compared with approximate estimation results.The results show that numerical simulation method can be used to calculate hydrodynamic coefficients.Through the CFD method and the dynamic grid technology based on the viscous fluid calculation,the direct motion,the oblique navigation,and the plane motion mechanism test are numerically simulated.The main coupling hydrodynamic coefficients of AUV are obtained by approximate estimation,the motion model is established and the effective action process of calculating the propeller and controlling the rudder is discussed.The motion stability in the horizontal and vertical surfaces is evaluated by using the gull discriminant method,the direct and rotary motion are simulated and a double loop integral sliding mode controller is designed to track the motion path of the motion.