Design And Analysis Of Underwater Hydraulic Manipulator

Underwater manipulator can be operated in the seabed.with Remotely Operated Vehicle(ROV)as the carrier.On the basis of fully draw lessons from foreign manipulators,this paper designed a five functions underwater hydraulic manipulator.At the same time,through the theoretical analysis and numerical simulation method,the kinematics,workspace dynamics and hydrodynamics of the manipulator was analyzed and studied.Firstly,according to the design index of underwater manipulator confirmed overall design scheme completed the hydraulic system and the structure design of the manipulator.Comparing several groups of data of the critical dimension parameters of the gripper and hydraulic cylinder of the manipulator,we find suitable parameters.In addition,the seal of the wrist of the manipulator was designed.Using Solidworks Simulation software,the key spare parts of the manipulator were completed by FEA(finite element analysis).Secondly,underwater hydraulic manipulator with five functions as the research object,the coordinate system was established with D-H method.According to the transformational matrix of each link,we established the mathematical model of the direct kinematics of the manipulators.According to the mathematical model of the direct kinematics,we derived out the relevant inverse kinematics equations.In addition,kinematics simulation was completed by using Robotics Toolbox,the correctness of mathematical model was validated.Then,on the basis of the kinematics of the manipulator,the workspace was analyed.According to the range of motion of each joint of the manipulator,horizontal operation space and pitch operation space were drawn by using the analytic method,the Monte Carlo method and the simulation method.In this paper,three different methods for drawing the workspace were compared,the simulation method is best,the conclusion is more completely,rapidly and accurately.Finally,using the Newton-Euler equation,the dynamic model of the manipulator in the air environment was established,and the recurrence equations of the joint torques were obtained.Considering that the working environment is in the deep sea,the influence of buoyancy forces,water drag and added mass on the joint torque of the manipulator is mainly considered,the hydrodynamic model of the manipulator is established by using the Morison equation.In order to study the dynamic characteristics of the manipulator in the air and water,using the linear interpolation method of parabolic transition,the trajectory planning of various joints of the manipulator is carried out.the joint torques of the manipulator in the air environment and in the water are studied by the methods of numerical simulation and quantitative analysis.