Research On Attitude Control Strategies Of Unmanned Underwater Vehicle

Unmanned Underwater Vehicle is a strong visual and perceptual system, can use theremote control or independent operation mode completed some specific tasks in Underwatermoving, It is a small self-propelled carrier, use UUV can complete deep sea exploration,Marine resources development and military Marine combat mission, etc. This requires UUVhave a high degree of autonomy, precise control and strong tracking ability, because of theUUV itself6dof strong coupling nonlinear characteristics, It is difficult to obtain theaccurate fluid power coefficient, complex water in the uncertainty of bring externaldisturbance and the load and the change of the homework caused by the influence ofperturbation. This makes the general controller is difficult to achieve the mission control,Therefore, we design has the strong robust controller is designed UUV independent sailingof the key.In this paper, we research on attitude control strategies of Unmanned UnderwaterVehicle, and the specific research work are listed as follows:Firstly, we set up UUV kinematics space motion coordinate system with investigate therigid body motion characteristics, through the coordinate conversion between UUV isdeduced the kinematics equations; analysis the rigid body dynamics, according to themomentum and solve dynamical problems derived dynamic equation theorem, the UUVestablishment of the mathematical model, the view of mathematics model contains strongnonlinear coupling, go against control model, and then the UUV mathematical modelaccording to the movement for decoupling simplified plane longitudinal and lateral motionmodel movement model.Secondly, we analysis fuzzy controller, sliding mode controller and their combinationof the control strategies, in order to improve the control performance, the improved fuzzycontroller membership functions of the method of improving the design of fuzzy slidingmode controller is proposed, in view of the fuzzy control output is difficult to determine theproportion of factor, the adaptive fuzzy sliding mode controller design to optimize scalingfactor, then the simulation experiment, this paper analyses these a few kinds of controllercontrol performance and robustness. Simulation experiments show that the improved fuzzysliding mode control and adaptive fuzzy sliding mode controller is steady-state error, smallovershoots, short setting time, and has strong anti-jamming ability, has good robustness.Thirdly, the fuzzy sliding mode control strategies on UUV control model of thelongitudinal motion is studied, and the underwater vehicle depth and elevation Angleprospective sliding mode control, traditional fuzzy sliding mode control, improved fuzzy sliding mode control and adaptive fuzzy control control performance and robustness; Lateralmovement of the course Angle control of the improved fuzzy sliding mode controlalgorithm, it is using sliding mode with width threshold size to judge the reaching lawsliding mode control and fuzzy sliding mode control, and finally obtain satisfactory controleffect.Fourthly, because of the axial movement control plays an important role in UUVprecise control, it mainly including the speed and position tracking control. Established inthe axial movement the state of the model equations, state variables for shaft to velocity andpropeller has speed, input of the motor torque applied for, the propeller thrust and torque foroutput, and we analysis axial flow speed use nonlinear observer and adaptive sliding modecontrol algorithm, finally we achieve the position and speed of accurate tracking control.Finally, we use these strategies for Unmanned Underwater Vehicle navigation attitudecontrol, through The simulation experiment, we obtained satisfactory control effect,indicates that the control strategies are feasible and effective, with high controlperformance.