Research On The Monitoring Method Of Hydraulic Equipment Running Status Base On The Electric Parameter Analysis

With the development of industrial automation, hydraulic equipments are more and more widely used due to the unique advantages. At the same time, the hydraulic equipments have become the mechanic-electronic-hydraulic integrated system, whose function is increasing and structure increasingly complex. The information and energy transfer progress of the hydraulic system has become quite complex. The system’s safety, reliable, energy-saving operation, and how to identify the malfunction omen, are the hot issue which attracts the attention of scholars home and abroad. Asynchronous motor is the main power source of the hydraulic system, and its three-phase electrical signals contain the global information of the hydraulic equipment operation due to the effect of coupling of the rotor. By contrast, the pressure signals and vibration signals have the characteristics of low letter noise ratio and limited feature information due to the multi-coupling and strong coupling of the hydraulic system. Therefore, develop the condition monitoring and power optimization control technology based on the electrical parameters to solve the problem of high failure rate and inefficient. After the depth study of the hydraulic system state recognition technology based on the fusion of electrical parameters, an condition monitoring method, which is intuitive, online and graphical visual, is developed. The main contents are as follows:Firstly, the state monitoring method based on electrical parameters was studied and find that the Lissajous fusion method can make good use of the large number of system state information carried by the three-phase electrical parameters. With the fact that the three-phase AC electrical singles mixed with high-order harmonics, negative sequence components, and the baseband signals can be a significant response of the operating conditions of motor and hydraulic system, Hilbert transform and coordinate transformation methods are chosen to extract the base frequency component of the three-phase electrical singles. The result shows that this extraction method ensured the speed and accuracy and meets the demand of online monitoring.Secondly, to design the running status online monitoring of hydraulic system by using LabVIEW software which is a graphical programming language. Design the program for on-line monitoring and off-line analysis resprctively to meet different requirements in practical application:The online monitoring system has realized the real-time acquisition and data processing of the motor’s three-phase electrical signals that achieve the purpose of the dynamic graphical visualization monitoring; The off-line analysis system original playback module, analysis module of the data, and the dynamic comparable module of the Lissajous fusion graphics which is needed in different condition; Calling for access to design the database management module by using the LabVIEW database toolkit which is convenient for the user’s query, modify, call.Lastly, simulating all kinds of working condition and texting the hydraulic system condition monitoring system based on electrical parameters in the hydraulic power system experiment platform which was built for system diagnosing by multi-source information. Through the contrast of the pressure and flow rate of signal, the text results show that the hydraulic system monitoring platform which we developed is reliable and practical that can provide technical support for the hydraulic equipment running status monitoring.