Optimization And Experimental Research On Flexible Joint Structure Of Nuclear Power Underwater Inspection Robot

As an important part of the clean energy system,nuclear power has the advantages of high productivity and low environmental pollution.At present,nuclear power accounts for an increasing proportion in the national energy system.Due to the particularity of its working environment,most of the nuclear power equipment are in a high radiation environment,and many detection and maintenance work need to be carried out underwater.The quality detection work in some key positions cannot be realized by manpower.Therefore,the nuclear power detection robot is of great significance to the daily maintenance of the nuclear power plant.For nuclear power detection robot,how to ensure that the detected surface will not be damaged in the detection process is one of the problems to be considered in the design process.Taking the 6-DOF manipulator as the research object,this paper studies the structural design of the flexible joint of the manipulator,and analyzes and designs the elastomer topology in the joint compliance module,which provides a certain reference for the application of underwater flexible joint.This paper designs a flexible joint with body compliance and torque output control ability for underwater manipulator,and designs the driving module,transmission module and compliance output module of the flexible joint.The kinematics and dynamics of the manipulator are calculated to verify the rationality of the joint selection,and the joint torque meeting the requirements of the contact force between the detection probe and the detected surface is calculated by using Monte Carlo method and force Jacobian matrix.The calculated joint torque is used as the design basis of the elastomer load in the flexible joint.The topological structure of the elastomer,the key component of the flexible joint compliance output module,is analyzed.A spiral topological structure in the form of circular arc connection is adopted to preliminarily meet the stiffness design requirements and torque bearing capacity of the elastomer.The finite element analysis of the elastomer structure is carried out by using the experimental design method(DOE),and the stiffness and bending stress of the elastomer under different structural dimensions are obtained.The optimization function model is established for the topology of elastomer.The variance of the difference between the stiffness and the target stiffness under different loads is taken as the optimization objective,and the objective function of the optimization model is taken as the reference basis for iterative solution to obtain the topology parameters that meet the design requirements.An elastomer deflection parallel and tooth embedded connection output structure is proposed.Aiming at the inconsistency between the elastomer output torque and the actual output torque of the joint caused by the friction of the rotating sealing structure in the underwater flexible joint,a linear dynamic control model is established for the joint on the premise of considering the friction of the rotating sealing structure,so as to provide a reference for the actual control of the flexible joint.Carry out the stiffness test of the elastomer to verify whether the linearity between the shape variable and the load and the actual moment bearing capacity of the elastomer meet the requirements.The flexible joint is tested to prove its torque output ability and the stability of bidirectional torque output,and further verify the rationality of the flexible joint structure.