Hovering Attitude Control Of Open Shelf ROV Based On Adaptive Robust Algorithm

With the growing human needs, the natural resources on land has been exploitedfor hundreds of years, which is unsufficient for the demand of mankind in the future.There are a lot of natural marine resources under the ocean covering71%of thesuperficial area of the earth, and this natural resource will be the only selection forproviding the energy in the future. So excavating and exploiting the natural marineresources will be the main developmental direction in the future. Because of the smallsize, wide scope of activation, enough power, burden capacity and more convenientoperability, The Remotely Operated Vehicle (ROV) will gradually become the maincarrier to work under the sea.A ROV with8propellers is designed in order to make the ROV move back tothe initial position set by the posture sensor in short time. According to thedistribution of the propellers, six degrees of freedom movement can be realized, twocoordinate systems are established for describing the movement of the ROV, and akind of transformation matrix between them is established. According to thehydrodynamic coefficients of the ROV, six degrees of freedom equations of motion isestablished, and the dynamic equation for describing the movement of the ROV isdetermined. Combined with the property of the ROV, some mathematical model ofsome parameters are simplified, finally mathematical model of the ROV can be get.There are many algorithms for controlling the unmanned underwater vehicles,for example, algorithm based on the model, PID Control, Adaptive Control, RobustControl, Neural Networks Control, Fuzzy Control, Iterative learning Control, VariableStructure Control and Backstepping Control. In all of them, because the adaptivecontrol is based on the Lyapunov function. When the ROV movement existsinterference or the model of ROV is established with deviation, the error will affectthe movement precision of the ROV assignments, because of its additive rationalinterference, the Robust Control can eliminate some interference, but it could not react accordingly to the specific interference. And it is also slightly stiff. The theory ofthe adaptive robust control algorithm is established in this paper, a controller of thehovering attitude of ROV in the underwater is designed, Adaptive Robust Algorithmhas been combined with the attitude control of the ROV.A simulation on the ROV with Matlab/Simulink software is made, and therelation between time and the output value and steady from the mathematics model ofROV The status of the Adaptive Robust Algorithm controller is analyzed, and thestability and reliability of Adaptive Robust Algorithms controller is verified. Throughthe bounded convergence error signal of the ROV, and the graphic comparison of theROV from the different collecting time, the feasibility about the Adaptive RobustAlgorithm is applied to attitude hovering control of the ROV is confirmed.The controller based on Adaptive Robust Algorithm can be applied to the fieldthat hovering attitude control of the open shelf ROV by modeling and simulationanalysis. And the controller is convergent, stable and reliable.