Design And Analysis Of A Spatial Translational Parallel Mechanism For Polishing Machine

With the rapid development of industrial technology and the increasingly high requirements for processing precision of manufacturing-related industries, the research direction of ultra-precision machining is being formed. As a significant part in the ultra-precision manufacturing, polishing can improve the accuracy by several orders of magnitudes and meet the requirements of industrial design in order to guarantee the rapid development of aerospace, weapons and other precision equipment industry.A three DOF translational paralleled mechanism according to the processing requirements is designed. Based on the stereo geometry method and the closed loop vector method, the forward and inverse kinematics models of the mechanism are established. By differentiating the inverse kinematics model, Jacobi matrix is calculated.The correctness of the kinematics model is verified by MATLAB and ADAMS simulation. According to the geometric constraints and assembly conditions of the mechanism, the constraint relation of structural geometric parameters is established by applying the theory of design space.The static model based on the principle of virtual work is studied and set up the stiffness index by mechanism stiffness matrix, which provides bases for stiffness analysis. The geometric parameters influence pattern on mechanism stiffness is studied by applying MATLAB numerical simulation.The dynamic model based on the principle of virtual work is studied. A simplified dynamic model is established by using the mass distribution coefficient method under the condition of light weight. The feasibility of the simplified model is verified by numerical simulation and analysis. The dynamic performance index is established, and the mechanism is analyzed by numerical simulation, which provides a theoretical basis for control.According to the error index D-H, error modeling method is studied and the influence of geometric parameters on the mechanism is analyzed. The identification model for mechanism error parameters is established based on the minimization of the maximum absolute value of the residuals. The output to be identified is solved by group search method, which provides the basis for error compensation.