Design And Analysis Of Multi-joint Manipulators For Underwater Welding Robots

With the development of nuclear energy,nuclear power plant construction,nuclear leakage and other safety accidents have received more and more attention and attention.Among them,the leakage of spent fuel pool and refueling pool is a typical nuclear power accident.While traditional manual maintenance methods are time consuming and labor intensive,it is important to develop a robot for underwater maintenance.This project combines the actual needs of the project to develop a lightweight multi-degree-of-freedom welding robot arm mounted on a frame-type underwater ROV.Firstly,the underwater welding process,the loading space and the working space were analyzed,and the five-degree-of-freedom configuration of the arm and the arm size parameters were determined.The general plug seal is used as the dynamic seal at the output shaft of the motor,and the aluminum alloy is used as the main material of the manipulator.Considering the effect of fluid-solid coupling,the selection and structure design of the motor are completed.Using ANSYS,the topology optimization design of the key components of the manipulator is completed.On the basis of guaranteeing the strength and stiffness of the components,the mass is reduced.The three-dimensional modeling of the manipulator is completed in SolidWorks.Then,the dynamic equation is modeled based on Lagrange method,and the hydrodynamic analysis is completed based on Merson method.The control moments under ground and underwater conditions are compared by Adams simulation,the rationality and reliability of the design are verified,and the influence of each joint of the manipulator on the ROV body is analyzed.Finally,the joint watertightness test was completed,the test platform of the underwater welding robot was built,and the single joint control test and the trajectory tracking test were completed to verify the rationality and reliability of the underwater welding robot designed in this paper.The accuracy of the hydrodynamic model is verified by collecting the underwater motion data of the manipulator with ATI six-axis force sensor.