Study On Assessment Method Of The Hydraulic Pump Health Condition

With the development of Chinese manufacturing equipment, the more advancedequipments are ,the higher demand for the degree and level of automation. If the giant andkey equipments which refer to national economy and the people’s livelihood break down,it will bring different degrees of economic losses. It is very necessary that assessing thehealth condition of the equipments and monitoring their work statement.Vibration signal of the bonnet of the swashplate axial piston pump can be acquired bythe sensor, then in order to obtain the frequency band including fault information, waveletpacket decomposition and reconstruction plays the role of band-pass filter. Waveletdecomposition and reconstruction algorithm denoise the frequency band of signal for thepurpose of the high SNR and the clear fault signature. Envelope demodulation algorithmbased on Hilbert transform is applied for denoised signal from the resonance signal. Lastly,the signal including the clear fault signature will be presented by means of demultiplingthe frequency to the band of 0-2000Hz. Feature can be extracted from the signal based onthe next signal processing requirement.Information entropy describes the degree of uncertainty and the complexity of thesystem state, which means that the more instable and the complex the is, the higher theinformation entropy is. By analyzing a large amount of data, it can be concluded that theinformation entropy theory will be effectual for the assessment of the health condition ofthe equipment.The sensor collects the vibration signal of the bonnet of pump with the differentdegrees of camber wear of the one skid shoe. The feasures that are the information entropyincluding singular spectrum entropy in the time domain, power spectrum entropy in thefrequency domain and wavelet energy spectrum entropy and wavelet coefficient energyspectrum entropy in the time-frequency domain, can be extracted from the vibration signalafter series of process. Based on experiment and the date analysis, the higher the degreesof uncertainty and the complexity is, the higher the information entropy is, the healthcondition of the equipment can be assessed successfully. In a word, information entropy is a effectual index, it can be effectifully used in assessing the health condition of thehydraulic pump.