The Theory Analyse And Research Of 2-RRUR/2-RPUR Asymmetric Parallel Machanism

With the development of parallel mechanism research, technology and application,the spatial imperfect-DOF parallel mechanism has received more and more considerableattention of the scholars all over the world and has a broad perspective in industryproduction and other fields for the advantage of simple mechanism, easy control and lowcost, compared with the traditional six-DOF parallel mechanism. Most of the traditionalimperfect-DOF parallel mechanisms have identical branch, symmetric construction andisotropy, while the unsymmetrical imperfect-DOF parallel mechanism becomes a newresearch focus because of its special working occasion. In this dissertation, on the basis ofanalysis the current situation of the theoretical research and application of imperfect-DOFparallel robot home and abroad，the theoretical research relating to this new type of2-RRUR/2-RPUR unsymmetrical 4-DOF parallel mechanism is analysed and researched.Firstly, on the basis of the analysis of kinematic characteristics, use the D-H methodto get the institutional position negative solution expression, and specific values to verifythe correctness of the expression. Then based on the methods of screw theory, analyze therationality of two sets of input selects of parallel mechanism, and compare the pros andcons of these two sets of reasonable input selects in order to get the most reasonablecombination of input.Secondly, on the basis of the space limit boundary value search method, analyze theworkspaces of this new type of parallel mechanism, considering the limit and influence ofthe rod length and the turning vice corner. And draw the shape of the workspace by 3Dsimulation software, and then analyze the singularity form.Finally, establish the dynamic model of parallel institutions with the method of theLagrangian, including the dynamic calculations of the moving components. And using theADAMS simulation software for kinematics and dynamics simulation，map out thekinematics and dynamics performance curve.The research of this thesis establishes theoretical basis for the further research anddevelopment of this 2-RRUR/2-RPUR unsymmetrical 4-DOF parallel mechanism, and it has some significance in other similar analysis of the spatial imperfect-DOF mechanisms.