Application of the discrete wavelet transform to fault detection of angular measuring system of a precision servo turntable

The angular measuring system is the most important component of servo turntables in inertia test equipments, its function and precision determine the turntable´s function and precision. The angular measuring system of a precision servo turntable is investigated in this paper. One phase input voltage amplitude of an inductosyn becomes discontinuous because of circuit faults, which results in the system error exceeding the allowable error and reduces the system accuracy, so the discontinuity point needs to be detected. The discrete wavelet transform is presented as a signal processing technique; it analyses the signal in angular and frequency-domains. Thus the useful information in the error signal is obtained from the multi-level discrete wavelet transform decomposition. The experimental result shows it is practical and effective to detect the faults.