Fault Degradation Assessment of Water Hydraulic Components by Noise Signal with Wavelet Packet Analysis

Abstract

Abstract Vibration analysis contains the important information for the working condition of the mechanical system. It is the major method used in condition monitoring and fault diagnosis of machinery. However, noise is widely recognized as one of the more characteristic aspects of hydraulic power system. The flow ripple generated primarily by motor/pump is the main source of acoustic signal. The characteristics of the noise from water hydraulic system have a close relation to the fault degradation of the pistons inside the water hydraulic motor. This paper studies the fault degradation of the piston in the water hydraulic motor by noise in the vibration signal. The fault degradation of the piston in the water hydraulic motor is introduced to acquire the vibration signal of the water hydraulic motor under different pressures. Wavelet packet analysis is applied to analyze the vibration signal to obtain the noise from the vibration signal of the water hydraulic motor. Continuous wavelet transform is used to analyze the noise within the specific frequencies. The results show that the noise of the water hydraulic motor has the different feature values under different fault degradations.