Workpiece Thickness And Defect Detection Based On Ultrasonic

As we all know,ultrasonic defection technology has the advantages of wide detection range,high sensitivity,low cost,high efficiency,harmless to human body and so on.With the maturity of ultrasonic testing theory,it is playing a more and more important role in ensuring the quality of products and meeting the demand for high-precision products.At this stage,signal processing technology and computer technology are developing rapidly,the application of embedded technology in ultrasonic testing equipment is more and more extensive,so that the ultrasonic testing equipment is continuously improved in digitalization,image processing,miniaturization and real time.Based on the actual requirements of ultrasonic thickness and defect detection,this paper puts forward a reasonable embedded development scheme and a reliable hardware scheme.The paper has improved the algorithm of ultrasonic echo parameter estimation.The innovative work of this article includes the following points.(1)The paper has given an embedded scheme with S3C2440 chip as the core of control and calculation.By analyzing the working principle of ultrasonic transducer,the paper has designed a transmitter module based on Boost circuit.According to the actual echo waveform and hardware requirements,the article has designed an amplification filter circuit based on MAX4212 EUK chip.The paper has designed a clever signal modulation circuit to obtain the precise ultrasonic echo transit time.All of this provides a new hardware solution for the subsequent ultrasound detection system.(2)The paper has proposed an echo parameter estimation algorithm based on improved ultrasonic echo preprocessing.Firstly,the algorithm uses the signal modulation method implemented by hardware to intercept the actual measured ultrasonic echo in time domain,so that the data processing speed has been improved.Secondly,then the paper has designed a preprocessing method of echo signal based on FIR filtering,empirical mode decomposition(EMD)and initial value solution.And finally the EM algorithm is improved by using the initial value.The simulation results show that the algorithm can accurately estimate the parameters of the multiple echo vectors,and the estimation error is less than 1%,the speed of parameter estimation is three times faster compared with the EMACO algorithm,and the most important is that the new method has a higher practical value.(3)The paper has given a complete ultrasonic testing system,and use it to test some specific workpieces.The actual detection scheme,the defect detection data calculation methods and the processes to achieve operational that the paper has proposed have significance guidance to the ultrasonic testing operation.There's a solution that include the inter-process communication,the echo estimation algorithm,the interface program,and the code logic,which had provided a new software development ideas for ultrasonic testing.The actual test results show that the designed thickness of ultrasonic testing system and defect location detection error is less than 1%,and the error of defect size estimation is 15%,that had satisfied the requirements of ultrasonic testing system for accuracy and real-time.