An attempt to relate dynamic tracking error to occurring situation based on additional rectilinear motion for five-axis machine tools

Qicheng Ding,Jing Zhang,Li Du,Jiexiong Ding

doi:10.1177/1687814020967573

Qicheng Ding, Jing Zhang + Show 2 more

Open Access

https://doi.org/10.1177/1687814020967573

Copy DOI

Abstract

During five-axis CNC machining, the dynamic tracking error of the five-axis machine tool caused by imperfect servo dynamic performance is the major factor affecting the accuracy during high-speed and high-precision manufacturing. Rotation tool center point (RTCP) test has become a typical kinematic test for the dynamic tracking error of five-axis machine tools. According to the mechanism and characteristics of dynamic tracking error, during the RTCP test, relating the measured dynamic tracking error to corresponding occurring situation is helpful for the research of calibration or reduction of dynamic tracking error. In this paper, a new method to relate dynamic tracking error to occurring situation based on additional rectilinear motion is attempted. During this method, rectilinear motions are added into the RTCP test process, and the dynamic tracking error and corresponding occurring position can be calculated from the scale of rectilinear motion. By six tests with rectilinear motions in and against X, Y and Z directions, the additional error and uncertainty of the test process can be offset by calculation. This method can be implemented without any addition or modification to the instrument or NC system.

Highlights

Five-axis CNC machine tools are at the core and forefront of the high-end manufacturing industry due to high efficiency and precision
A new method to relate dynamic tracking error to occurring situation based on additional rectilinear motion is attempted
Rectilinear motions are added into the rotation tool center point (RTCP) test process, and the dynamic tracking error and corresponding occurring position can be calculated from the scale of rectilinear motion

Summary

Introduction

Five-axis CNC machine tools are at the core and forefront of the high-end manufacturing industry due to high efficiency and precision. Some researchers chose to measure the tool tip deviation by RTCP device, collect the corresponding axis positions, velocities and accelerations, and build the relationship by time alignment matching,[19] as equation (16) shows: ðDX , DY , DZÞ 0. Corresponding occurring situation are acquired; second, as a contrast, the ordinary RTCP test (without additional rectilinear motions) with the same trajectory and experimental setting was performed, and the dynamic tracking errors were acquired; the tracking errors acquired by the two tests above were compared to verify that the ‘‘error to corresponding occurring situation’’ relating method can be implemented without additional deviation. The experiment was conducted as follows: first, the RTCP test with additional rectilinear motions was performed, and the dynamic tracking errors and (1) If only the rotary axes are set to move, F is defined as the resultant angular velocity of the two rotary angles, as calculated according to equation (29): sffiffiffidffiffiAffiffiffi(ffiffitffi)ffiffiffiffi2ffiffiffiffiffiffiffiffiffiffiffidffiffiffiCffiffiffi(ffiffitffi)ffiffiffiffi2ffiffi.

Experimental results and analysis

Conclusion

21. ISO 10791