Stiffness Analysis And Optimization Of A Redundantly Actuated Parallel Module

The situation is that China has great requirement of Friction Stir Weldingequipments for aircraft manufacturing, pipe restoration in water and so on. Under thisbackground, with the fund of National Nature Science Fund committee and TianjinResearch Program of Application Foundation and Advanced Technology, in this thesis,inverse position analysis, general Jacobian matrix and stiffness analysis together withstiffness design optimization of a redundantly actuated parallel module of the hybridwork unit Tricept-IV is investigated. The research achievements are list blow:1Inverse position analysis and general Jacobian matrix. On the basis of specialtopology of the redundantly actuated module and its work principal, vectormethod is used to carry out inverse position analysis of the module. By meansof screw theory, the general Jacobian matrix including actuation Jacobianmatrix and constraint Jacobian matrix is derived.2Stiffness modeling. The actuation stiffness matrix and constraint stiffnessmatrix with clear physical meaning are obtained by using screw theory andredefinition of the unit force wrench and unit motion torque. Finite elementanalysis in typical configuration, with consideration of stiffness of bearings andhinges of the module, verifies the analytical stiffness model. Based on thestiffness model, stiffness evaluation of the module is carried out in this thesis.3Stiffness design optimization. Based on four global stiffness indices andanalytical stiffness matrix, sensitivity analysis is applied to reveal the influenceof section parameters of key components to the module’s stiffness. The fourglobal stiffness indices are selected as objective function and a modified geneticalgorithm is used to optimal design important section parameters withengineering constraints. According to the optimal result, virtual prototype of themodule is reconstructed and then imported into finite element analysis softwarefor static structural analysis. The result verified the validity of the optimal design and its value for engineering reference.