Development Of Multi-channel On-line Detection System

With the progress and improvement of virtual instruments and various sensors,the continuous development of online detection technology is promoted.The detection system is an indispensable link in the production and maintenance of enterprises to ensure product quality.It can solve a series of problems such as reducing labor costs and improving product quality.Based on the engineering practice,the hardware system is designed and built,three functional modules are compiled,and a multi-channel online detection system is developed.The main works of the project are as follow:(1)The overall design of the system is planned according to the system requirements and the idea of functional modularization.Secondly,the hardware devices such as data acquisition card,sound sensor,pressure sensor and proximity switch are selected.On this basis,the interface between sensor and acquisition card is solved,and the hardware system is designed and built.(2)LabVIEW software is used to program the general interface and functional modules of the multi-channel online detection system.The basic function module of the system includes signal real-time acquisition sub module,which can carry out multi-channel on-line acquisition task;time-frequency analysis sub module,which stores the collected signals into txt files,and browses the signals offline,and carries out Hilbert transformation,FFT,power spectrum,mathematical statistical analysis,for the txt files browsed offline.Basic analysis: the basic function generator is programmed in the signal generator sub module,and the output port of the acquisition card is used to output the signal.(3)The module of signal de-noising and feature parameter extraction compiles the algorithm of signal de-noising and feature extraction.A continuous threshold function is proposed to improve the traditional wavelet de-noising method,and the improved algorithm is compared with the traditional algorithm.The Mel frequency cepstrum parameter(MFCC)and its first-order difference coefficient of the sound signal are extracted as the characteristic parameters of the signal.(4)the special module of material detection puts forward the recognition of steel material by using its sound signal and shear pressure signal through the research of punching experiment of machine tool.The online steel material recognition is carried out by combining the European distance based on the characteristic parameters of punching sound signal and the threshold detection of shear pressure signal.Finally,the hardware and software are tested and installed on site.The actual signal acquisition experiments are carried out in the laboratory and factory.The experimental results show that the system has good operation,comprehensive functions,good scalability and versatility,and can be used for multi-channel online detection and data collection tasks.It is more accurate in the steel material testing results,and solves the time-consuming and laborious situation of traditional testing methods.