The Research Of Autocontrol Technique Of Balance System Used To Variable Mass Autonomous Underwater Vehicles

Autonomous Underwater Vehicles(AUV) are applied to civil and military affairs extensively,for example, oceanography, alert and attack on the sea. At present,AUV develops toward to long voyage,large depth and more functions. Variable mass AUV is a special AUV,whose dynamic system hybrid thermal power and electric power combination, and it schleps load for its assignment.With fule consumed and load released and the density change of navigable waters,Variable mass AUV loses in static balance.In this case,the prejudice of AUV’s security, economy and secret.The paper analyses variable mass AUV’s dynamics and kinematics characteristic according as its collectivity design,then establishs the equation of variable mass AUV motion with six freedoms.In order to maintain the static balance of variable mass AUV,The paper designs the automated balance system.It consists of the central ballast system, fore-and-aft balance system,load weight compensating balance system and emergency ballast system.Then the paper establishs the mathematical model of the automated balance system according to its operation principe.A simulation model of the automated balance system of the variable mass AUV is built in Matlab/Simulink. Mathematical simulation is done in the cruise state, emergency state and load releasing state of the variable mass AUV. By analyzing the simulation data, we find that the automated balance system can make the variable mass AUV cruising safely, economically and covertly. When it encounters an emergency case, like passing a freshwater area, by increasing its speed properly,the automated balance system can make the AUV escaping from the danger. The variable AUV must speed itself up before load releasing, and the automated balance system can ensure the AUV’s and the load’s safety during this process.According to the mathematical simulation result of the variable mass AUV, and combining with the analysis about other AUV’s real cruising test data, we can make the mathematical simulation of the AUV under the simulation real cruising condition more accurately. Under the real cruising condition, because of the wave and ocean current disturbance, AUV’s helm angles and attitude angles seesaweds slightly in the quasi-steady-state.The paper uses the fuzzy theory and designs fuzzy controller to simulate the variable mass AUV under the real cruising condition. By analyzing the simulation data, we can find that using fuzzy theory to design the automated balance system can make the variable AUV cruising more securely, economically and secretly.The paper provides a theoretical basis for the system design and component selection of the project design of the variable mass AUV’s automated balance system,according to the mathematical simulation result in ideal condition and real cruising condition.Finally,the paper provides the key technology and research method of the project design of the variable mass AUV’s automated balance system.