Dynamic measurement of the positioning accuracy of redundantly actuated parallel machine tool

A 5-DOF 5-UPS/PRPU parallel machine tool (PMT) is introduced. Redundant actuation is adopted in order to improve the positional accuracy and dynamic performance. A method for the measurement of positioning accuracy of PMT under dynamic condition is described in detail. It is based on Agilent 5529A dual-frequency laser interferometer which is capable of performing dynamic calibration. Based on the working principle of laser interferometer, the positional data of the moving platform are collected and the positional error data in accordance with ISO 230-2 standard of each virtual axis are obtained in high resolution. Meanwhile, the positioning accuracy of each axis is also descried with visual graphics. In order to investigate the influence of redundant actuation on the positioning accuracy of the machine, the linear positional error of X-Axis are both tested under the redundant actuation case as well as its corresponding non-redundant counterpart. These positional error data can be used for the positional error compensation model of machine tool.