A Wavelet-Based Approach for Diagnosis of Internal Leakage in Hydraulic Actuators using On-Line Measurements

Abstract

AbstractPrompt diagnosis of faults associated with hydraulic actuators is important to maintain reliability and performance and to avoid complete loss of functionality. This paper presents new development and evaluation of a wavelet-based method, intended for on-line detection of internal leakage in a valve-controlled hydraulic actuator. This work is built upon the initial study by the authors, in which actuator's internal leakage was detected using limited-duration data on one of the actuator's chamber pressures, in response to a structured input signal and under no load condition. In the present work, the more realistic case of an actuator that is driven in a closed-loop mode to track pseudorandom position references is considered. Additionally, the actuator is subject to loading. Furthermore, limited-duration pressure signals are obtained using a sliding window technique applied to the stream of on-line measurements. It is shown that the root mean square values of level two detail coefficient vectors o...