Study On Filtering Method Of Fault Vibration Signal Of Hydraulic Pump Under Sinusoidal Loading Condition

Hydraulic pump as the core of the hydraulic system,its working condition is good or bad for the whole device has a very important impact.The vibration signal of the axial piston pump under the sinusoidal load not only produces amplitude modulation,and the speed fluctuations will change the original vibration characteristics.So that the signal appears obvious non-linear,non-stationary characteristics.In response to these two aspects problem,based on mathematical morphology and order ratio analysis method,the filtering method of vibration signal of axial piston pump under sinusoidal load condition has been studied.Firstly,in order to find an effective processing method to solve the variable load hydraulic pump vibration signal amplitude modulation phenomenon,a multi-scale morphological filtering method is proposed,which based on morphological filtering complex evaluation system multi-scale optimization principle constructed by impinge characteristic ratio and second order origin moment.Through the vibration signal analysis of the simulation signal and simulated sine load we can say,this method can not only eliminate amplitude modulation phenomenon of the sine load hydraulic pump vibration signal,but also can extract the shock characteristic component of the signal.Secondly,considering the variable load conditions will not only make the amplitude modulation phenomenon of the hydraulic pump vibration signal,but also make the hydraulic pump speed fluctuation,and the speed fluctuation will have a certain impact on the vibration signal.In order to be able to eliminate this effect,taking the square wave load hydraulic pump vibration signal as an example,the time-frequency analysis order-tracking method was applied to the signal analysis.The mechanism of speed fluctuation under square wave load condition was verified by experiments.At the same time,the time-order ratio analysis method can effectively obtain the characteristic order of the experimental vibration signal.Finally,considering the influence of vibration signal feature extraction of sinusoidal load hydraulic pump.The order multi-scale morphological filtering method is proposed by combining multi-scale morphological filtering method and order ratio analysis method.And this method is used to deal with the vibration signal of sinusoidal load hydraulic pump.The results show that the proposed method can eliminate the two effects of the vibration signal feature extraction which under the sinusoidal load,and the vibration signal feature can also be extracted effectively.