Research Of Hydraulic Jack Leakage Diagnosis Base On Wavelet/AMEsim

Hydraulic system in many industrial applications play a very important role, in the event of failure, the economic losses will be very large. How to ensure that the hydraulic system operate safely, which has become a very urgent issue. Therefore it is necessary to state hydraulic system monitoring and fault diagnosis, which can be found failures early and as soon as possible to avoid greater economic damage. Condition monitoring and fault diagnosis technology for the development of production safety equipment provided strong protection.Hydraulic cylinder in the hydraulic equipment plays an important role, its failure will have a direct impact on the normal equipment and work life. Hydraulic cylinder leakage is a common kind of fault, serious leakage not only pollutes the environment and to reduce the chamber pressure, hydraulic cylinder can't work normally. How to detecte the leakage of hydraulic cylinder timely, and maintain it is a very important issue. According to the tenets of transmission fluid, When the hydraulic cylinder leak, its work cavity pressure of the dynamic will change. So by analyzing the pressure signal of the hydraulic cylinder, might detect leakage of hydraulic cylinder when the hydraulic cylinder leak. Therefore the pressure signal analysis to determine the hydraulic cylinder leakage fault has become a key issue.The main elements in this paper:Firstly,introduced the method of fault diagnosis of progress based on the signal processing. The method is for the hydraulic system fault diagnosis based on wavelet analysis. Focus on the wavelet transform an excellent time-frequency analysis, Singularity signal detection and the concept of Multiresolution analysis.Second, expounded the hydraulic system leakage failure mechanism and causes.Summed up the leakage fault mathematical model. On this basis established the cylinder leakage mathematical model. Using the mathematical formula proved that the in-cylinder pressure rising or falling rate will be affected by the leakage of cylinder. These are the theoretical foundation for the next chapter of the simulation analysis laid.Finally, using the wavelet outstanding singular signal detection capability and graphical development environment in AEMSim for build Hydraulic cylinder's modele, simulation and dynamic performance analysis. Detect the turning point of pressure signal accurately. In order to accurately judge the hydraulic cylinder leak severity provide numerical basis. The method of wavelet transform to detect the leakage of hydraulic cylinder is feasible. After a large number of simulation tests, drawing up the pressure within the time difference with the leakage volume and the volumetric efficiency the curves. This provide a basis for analysis of state work of hydraulic cylinder. Simulation tests curve for the site managers understand the hydraulic system dynamic characteristics detect, diagnose and adjust to the system, the transformation has some reference value. The method also applies to a hydraulic circuit or the entire hydraulic system leak quantitative detection of faults.In this paper, the main results are:1. Based on the basic modules and object-oriented modeling method AMESim simulation software built a hydraulic cylinder position control system model greatly simplifies the modeling process. After the hydraulic cylinder inside the vent fault fault simulation, the wavelet analysis of the hydraulic cylinder leakage fault diagnosis arrival.2. Using wavelet analysis of the pressure signal detection singular study of the hydraulic cylinder leakage characteristics of the fault, in the loop as a back-pressure valve installed valve, so that the detection of fault hydraulic cylinder vent more easily. For the quantitative detection of Discharge from the hydraulic cylinder to provide a reliable data basis.3. Through simulation of the pressure build up turning point to poor timing and volume of China's hydraulic cylinder volume and the efficiency of the relationship between the curves. It's value for failure prediction of hydraulic cylinder on early and scene-system management.