Research Of Ultrasonic System Based On Nondestructive Testing

Ultrasonic nondestructive testing technology is one of the testing technologies which are widely used in industry. It is nondestructive, easily handling and reliable and it can test workpiece at any period from product to service. With the development of ultrasonic testing technology and digital signal processing technology, the digital ultrasonic testing system was invented. Compared with analog ultrasonic testing system, digital ultrasonic testing system is more accurate, reliable and flexible, and it is replacing the analog ultrasonic testing system and becoming the trend for sure. But at present the digital ultrasonic testing system has some disadvantages such as single method of ultrasonic testing, weak data processing ability and low rate of data communicating and so on.Based on the methods of ultrasonic testing and the disadvantages of the present digital ultrasonic system, an A-type digital ultrasonic testing system is designed, and it is used for testing axles, rails and so on. For achieving better testing results and wider scope of application, it integrates impulse reflection and penetration methods, bases on PC, and takes FPGA as its core, uses USB and uses chips and devices with high accuracy, low noise and high reliability. FPGA has good ability of digital signal processing, which can control circuit and process the ultrasonic echoes. The processing result is transmitted by high-speed USB interface to PC, in which wave display is handled. Based on the concept of modularization, the hardware of the system is divided into ultrasonic testing module, data acquisition and processing module and communication module, and FPGA controls the whole circuit and each of them takes kinds of actions to remove noise and improve accuracy.After finishing the design of hardware, the FIR filter and adaptive filter are introduced. First, simulation models are built by MATLAB and System Generator, and by simulation the performances of digital filters are verified. The designs and realizations of FIR and adaptive filters are finished by Xilinx ISE Design Suite.At last, the debugging of the digital ultrasonic testing system is introduced. From the debugging results of the circuits and digital filters, the system operates normally and the performance very excellent.