Coordinated Control Research Of AUV Recovery Based On Fuzzy Theory

The ocean has abundant biological resources and mineral resources, with the development of marine science and technology, autonomous underwater vehicle has been an important tool for ocean development, and its recovery is an unavoidable problem. AUV underwater recovery has incomparable advantages. The 6DOF dynamic control system of AUV is very complex for its strongly nonlinear and strong coupling. This thesis aims to find an effective control strategy and a control method for AUV recovery process. A variety of industry control methods is applied to the dynamic control of AUV, but the results are not satisfactory. According to the relationships between events and the features of AUV recovery, the whole process was analyzed based on the Hybird theory. One recovery strategy is proposed using the Petri net. AUV recovery control system is designed based on fuzzy theory. And finally the autonomous control of AUV recovery is realized.Firstly, the coupling of AUV recovery is analyzed based on the established mathematical model of it. The coordinate systems and the coordinate conversion are introduced, with the help of force analysis, the translational motion equations and rotation movement equations are got, the 6DOF mathematical model of AUV is got. And the model of the ocean current disturbance is established. Get the characteristics and coupling of manipulating by simulation. And then the reasons of the coupling are analyzed to set the controller parameters.Secondly, the hierarchical architecture framework of AUV recovery control system is designed based on the supervisory theory of discrete event dynamic system, including mission level, task level and behavior level. AUV recovery movement both have the continuous dynamic and the discrete events, and decompose it into a series of action combination, it is very important to clarify the relationship between events. The Petri net has incomparable advantage in dealing with concurrency and conflict. One AUV recovery control strategy is proposed, the mission level and task level models of the control system are given using the Petri net.Thirdly, the behavior level of AUV recovery control system is designed based on fuzzy theory. The hardware constitution of the AUV recovery system is given. Using fuzzy controller designing principle and method, appropriate subjection function and control rules are selected, Single DOF fuzzy controller of AUV is designed. One decoupling control method is proposed for the coupling of the AUV recovery process.Finally, using the distributed digital simulation platform, the simulation is designed to test the effect of the control system. We give the methods of setting parameters of the controller and the effects of them combined with the characteristics of AUV. The tests of basic control unit and decoupling control unit are given. The test of AUV horizontal control system is given. The test of AUV recovery control system having the currents'disturbances or not are given.