Research On Dynamic Characteristics Of The Multi-DOF Underwater Manipulator

With the further development and utilization of marine resources,underwater robot technology,the key technology of underwater space exploration and subsea operation,has broad application prospects.As an important part of underwater vehicle tools in marine development,multi-degree-of-freedom(Muti-DOF)manipulator has vital research significance for improving the quality and efficiency in the underwater operation.The research object of this paper is a six-degree-of-freedom manipulator applied to subsea environment.And the research focuses on the modeling and analysis of its kinematics and dynamics.Firstly,by analyzing the joint parameters of the manipulator,the homogeneous transformation matrix of the linkage coordinate system is obtained based on DenavitHartenberg method,and the kinematics equation of the manipulator has been established and solved.And the correctness of the manipulator model and the forward and inverse kinematics solution has been verified by the simulation in Matlab.The workspace of the six-degree-of-freedom manipulator was also been analyzed by Robotic Toolbox.Secondly,based on the recursive Newton-Euler vector mechanics method,the dynamics equation of the manipulator has been established,and the analytical solutions of the speed,acceleration of the links and the forces and moments on the joints are obtained by computer compilation and iteration.Then the dynamic equation of the sixdegree-of-freedom manipulator considering Morison fluid resistance under hydrostatic condition has been established,and the analytical expression of the hydrodynamic moment of the base joint has been obtained.Finally,under the planned joint angular motion curve,the driving torque and water resistance moment of the base joint for the six-degree-of-freedom manipulator are solved,and the force control manipulator was modeled and simulated by using MATLAB/Simulink.The influence of the control torque and fluid resistance torque on the base joint of the six-degree-of-freedom manipulator was analyzed.