Task-Priority Coordination Planning And Adaptive Sliding Mode Trajectory Tracking Control For Underwater Vehicle-Manipulator System

The underwater vehicle-manipulator system(UVMS)needs the coordination between the vehicle and the manipulator to accomplish the specified underwater maneuvering tasks.The coordinated control technology of the underwater vehicle-manipulator system(UVMS)is the core technology to solve the coordinated motion between the vehicle and the manipulator,which includes the coordinated motion planning between the underwater vehicle and the manipulator and the joint space trajectory tracking control of the UVMS.However,the strong coupling and high nonlinearity between the underwater vehicle and the manipulator make the already complex cooperative operation of the underwater vehicle and the manipulator more complicated and difficult to control.Therefore,how to realize the efficient and high-precision coordinated control between the underwater vehicle and the manipulator has become the research focus of this dissertation to promote its wide application in practical underwater autonomous manipulation.The main work of this dissertation is as follows:The structure of the UVMS experimental prototype is designed,and its kinematics and dynamics models are deduced.The hydrodynamic coefficient of UVMS is calculated by the modified empirical formula method,and the additional mass and damping terms calculated by the modified empirical formula method are verified based on CFD technology.The simulation verification platform of UVMS is built to verify the correctness of the established kinematics and dynamics models.To solve the problems of high motion redundancy,kinematic singularity and inconsistent dynamic response of each subsystem in UVMS motion planning,a coordinated motion planning method of UVMS dexterity preservation and sweep optimization based on task-priority redundancy resolution scheme is proposed.The method realizes the full use of the redundant degrees of freedom of UVMS to solve other moving targets other than the main task,and plans the joint space motion trajectory that meets the requirements of the task,which improves the coordination,flexibility and efficiency of UVMS.For the problems of joint space trajectory tracking control of UVMS under large comprehensive uncertainties,an adaptive fractional-order sliding mode control method is proposed,which solves the problem that the fixed switching gain cannot effectively balance the control accuracy and chattering,and the tracking performance is obviously degraded under external interference.On this basis,an adaptive fractional sliding mode control method based on nonlinear disturbance observer is proposed,which further improves the system control performance and ensures the underwater maneuvering accuracy of UVMS.Combined with the proposed coordinated motion planning method and the traj ectory tracking control method,coordinated control experiments for performing uniform sweeping tasks and performing underwater capture tasks are carried out.The feasibility of the overall coordinated control of the UVMS is verified,and it is proved that the UVMS can accurately complete the underwater continuous manipulation task under the blessing of the proposed coordinated control scheme.