Research On The Structure Parameter Calibration And Machining Technology Of A 5-UPS PMT

The thesis investigates the issues related to parallel machine tool at home and abroad and focuses on the study and analysis of a series of aspects such as source of structure error, structure parameters calibration, machining etc. of a 5 axis virtual CNC machine tool which is based on a novel 5-DOF(5-UPS) spatial parallel mechanism.The structure and characteristics of the 5-DOF PMT are basically described and the source of structural error is analyzed. Based on the reverse kinematics solutions, the configuration of mobile platform are analyzed and the relation between the structure error and the error of the configuration of mobile platform is established.The kinematic model of constraint limb is developed. According to the kinematic model of constraint limb, one method of structure parameters calibration which adapts to 5-UPS PMT is presented. the method is to practical parameters as unknown are used to reverse kinematics solutions to establish new equations and we make mobile platform move to different pose, So the practical parameters can be figured out according to the reading of 5 sense organs and 5 limbs of 5-PMT. The correctness and effectiveness of the approach are verified by experiment.An example of a marine steamship blade is given, the parametic cubic B curves are used for surface fitting and the concrete algorithm is presented. Thisthesis gives the principle of selecting cutter and the advantages of the flat-end cutter 5-axis NC machining against the ball-end cutter 3-axis NC machining are analyzed. The formulas for cutter location, cutter axis, step length and path interval are proposed and the method of transforming the cutter location and cutter axis in the workpiece coordinate to the pose of the mobile platform .