The Study On Broken Wire Detection Of Steel Ropes And Virtual Instrument Development

Steel ropes were widely used in many industries, such as mining, metallurgy, transport,port, tourism. The complex structure and the bad environment made it easily abraded,corroded, fatigue and wire broken. Once the Steel ropes broken in running, they will causetremendous casualty and economy loss. Therefore, steel wire’s damage detection has beenattached great importance to the countries in the world, to become a world-wide phenomenon,both theoretical as well as practical value of the important research topic.This paper focused on broken wire rope injury. Based on the comprehensive analysisand discusses the form of wire rope damage and the principle of magnetic flux leakagedetection, the excitation device and signal detective device of steel rope, method of signalprocess in wire damage signal and neural network etc were deeply studied. Further the virtualinstrument system of broken wire detection was developed.Firstly, this article described the principle of magnetic flux leakage detection andleakage magnetic field characteristics of wire ropes, established equivalent magnetic circuitmodel. Based on anglicizing magnetic structure parameters by modeling, the excitationdevice was designed and excitation capability was verified by experiments, sequently linearintegrated Hall was chosen to detect signal of magnetic field leakage of the broken wire, thenumbers and distribution of Hall elements on the test results were analysed, then the signaldetector and preprocessing system were developed in order to eliminate the influence of eachkind of unwanted signal to the source signal of brokenl wire.Secondly, variable threshold value equation was established to solve each highfrequency coefficient quantification question of wavelet multi-layer decomposes using thesuperiority of the wavelet analytic method in processes on the non-steady signal. Based onthis the wavelet denoising algorithm was developed to eliminate the high frequencyinterference signal, through transferred Matlab in LabVIEW to replace the hardware by thesoftware to realize the denoising of broken damage signal. Wavelet energy was proposed as anew characteristic quantity, given the computation equation, and the signal characteristic value extraction algorithm was developed based on LabVIEW. And the multi-layered BPneural network model of quota recognition on the steel wire was established using the Matlabneural network toolbox, the network large-scale training in LabVIEW using the databaseformidable data capacity was realized combinding LabSQL with the Access databasetechnology, and the network accuracy and the stability was confirmed.Lastly, based on PXI-6281data acquition card of NI company in United States, the dataacquisition system of broken wrie damage singal was developed.Subsequently, the virtualinstrument system of broken wire detection was developed. This system has realizedfunction integration and the intellectualization.of broken wire detection in the steel ropesand included subsystems such as data acquisition and storage, signal processing anddatabase management which both may alonely complete the specific function andaccomplish the recognition of broken wire together. So, this system has friendly anddirect-viewing interface, easy operation, stronger functions and high degree of automation,which facilitated enormously the project of the steel rope damage diagnosis.