Research And Development Of Broken Wire Rope Inspection System Based On Virtual Instrument

The steel wire rope is a flexible component which is widely used in engineering. With the rope used more widely, the security accidents caused by broken wire rope have been increasing and therefore the study of steel wire rope's non-destructive testing technology is essential.The paper takes the detection of broken wire rope defects as the main object. On the basis of the domestic and foreign scholar's research in broken wire rope's testing and the construction of wire rope, the form of broken wire rope and its characteristics are analyzed. According to the wire rope's strong magnetic capability characteristics, the detection of broken wire rope is achieved using electromagnetic detection method by virtual instrument technology, and the virtual instrument system for steel wire rope detection is developed.In this paper, the principle of magnetic flux leakage testing method for local defects (Localized Fault, referred to as LF) of wire rope breaking is analyzed; the magnetized ways of steel wire rope and their respective magnetic characteristics, advantages and disadvantages are discussed; the program of rope excitation based on permanent magnetic properties, the structure of magnetic circuit excitation for steel wire rope and relevant magnetic circuit parameters are determined; the magnetic materials are selected; the magnetic intensity is analyzed; the wire rope excitation device is designed, and the magnetization of steel wire rope is achieved successfully.The detection program for broken wire rope based on hall element is established; the hardware circuit of detection system is designed; the detection system for steel wire rope is built, and the acquisition of broken wire signal is achieved successfully. Experimental results show that the system can meet the needs of broken wires detection.As the broken wire rope damage signal is a local anomaly signal that is random arise, and is usually superimposed on the background noise signal, and has a complex frequency components, the method of wavelet transform is used to pretreat the broken wire damage signal in the paper. The characteristics of the signal are researched; the characteristic parameters of broken wire signal are analyzed and extracted, and the RBF neural network for broken wire's identification is established.A virtual instrument system for broken wire rope testing based on LABVIEW environment is developed by virtual instrument technology. It integrates data acquisition, data processing and pattern recognition of broken wire, etc. together, and has the advantage of easy to operate, high flexibility and good visualization. Lots of experimental results show that the system for wire rope break detection based on virtual instrument developed in this paper can be well used in the detection of broken wires state. The rate of broken wire detection is greater than 90%.