System Development And Attitude Control Of Intervention AUV

Autonomous underwater vehicles(AUVs)tend to be lighter,more autonomous and capable of multiple tasks.They are generally used as platforms for surveillance,inspection,and obser-vation while lacking manipulation capabilities.An AUV with manipulation functions is called intervention AUV(IAUV).In this thesis,an IAUV is developed to carry different underwater devices for diversified tasks.It also has versatile movement patterns by adopting configurable propelling solutions to meet requirements of diversified tasks.The mechanical design of the IAUV is detailed in the thesis.The IAUV is a nonlinear cou-pling system under non-structural disturbances.A CMAC neural network robust adaptive con-troller is developed to control the posture of this underwater vehicle.It is proved that this control scheme achieve the stability through Lyapunov function.By comparing the different controllers,it is verified that the methods can not only adapt to the system's non-structural variation quickly but also control the posture stably.The IAUV may work at different depth in water.It will be energy consuming if propellers are used to control the depth all the time.Therefore,it is necessary to develop a buoyancy adjustment module(BAM).In the thesis,a novel hydraulic BAM is proposed.The mechanical design and dynamics model of the BAM are discussed.A time-optimal Bang-Bang control law is presented to achieve accurate depth control.It is investigated that the switching sequence exists through maximum principle.Further,a varying structure controller is developed which combines the PD and the time optimal control.It is not only time-saving in large scale depth but also accurate when nearing the target depth.