Diagnosis of the coupling misalignment of the vertical comprehensive performance test instrument of high precision reducer for industrial robot

Abstract

An instrument with a vertical layout and a cylindrical structure is designed to achieve the comprehensive performance testing of precision reducers. The inevitable coupling misalignment of the instrument can lead to vibration faults. So, it is necessary to diagnose the coupling misalignment while the device is working. The relationship between the misalignment fault and torque ripple are analyzed. A method using the Order spectrum analysis and Power spectrum analysis of the torque signal to diagnose the coupling misaligned fault is proposed. As a comparison, the traditional misalignment fault diagnosis methods have been used in the experiment. Experiment results show that it’s easy to quantitatively analyze the characteristic of misalignment using the amplitude of fr and 2fr frequencies and the power of the additional components of fr, 2fr, 4fr, and 8fr. But it’s hard to diagnose the characteristic of misalignment using the vibration signal because the collected signal is often non-stationary.