An efficient method for identification of motion error sources from circular test results in NC machines

Abstract

This paper proposes an efficient method for the identification of motion error sources involved in NC machines by the circular test, which is often used in estimating the motion accuracy of NC machines. The motion error signal from the circular test is classified into two fundamental patterns: a nondirectional error pattern (the mean of the clockwise and counterclockwise test signals); and a directional error pattern (deviation of clockwise or counterclockwise test signals from a nondirectional error pattern). The present paper proposes two identification schemes: the frequency analysis method and the weighted residual method. The frequency analysis method is used for identifying error sources of the nondirectional error pattern and the weighted residual method is used for identifying error sources of the directional error pattern. A menu-driven, user-oriented computer program is written to realize the entire proposed identification procedure. The proposed identification method is applied to two typical circular test results in order to verify its effectiveness.