Five-degrees-of-freedom error motion measurement method of precision rotary table based on BMPES

Abstract

It is essential to obtain the 5-DOF errors motion of the rotary table for reconstruct-ing the real trajectory of the rotating shaft, but there are many error coupling prob-lems when measuring the error motions of the rotary table. In order to improve the measurement accuracy of the 5-DOF error motion of the rotary table, a method of measuring 5-DOF error motions based on BMPES (Bidirectional Multi-Point Error Separation ) is proposed. Firstly, by analyzing the motion characteristics of the ro-tary table with multiple degrees of freedom error during the rotation, a detection system with double-layer structure probe arrangement is designed. Then, the three-point method is used in the radial direction to separate the roundness error of the measuring disk, which improves the measurement accuracy of radial error. Finally, the coupling relationship between the mixing errors collected by the axial probes is researched, and a face-four-point error separation method is proposed, which can separate the flatness error of the lower surface of the measuring disk complete the decoupling of the tilt error and the axial runout error. Simulation results show that for the measurement of radial, tilt and axial errors, the measurement errors of the BMPES method proposed in this paper are reduced by 97.89%, 68.40% and 99.99%, respectively, compared with the five-point method, and when eccentricity errors exist, the measurement errors of radial and tilt errors are reduced by 99.06% and 85.67%, which verifies that the method can accurately obtain the five degrees of freedom motion of the rotary table errors.