Design Of Digital Control System For Ultrasonic Phased Array

Ultrasonic phased array detection is a high-level detection technology and research hotspot in the field of nondestructive testing,and it has been widely used in industry.The digital control system is the core of the ultrasonic phased array instrument.The improvement of the function and performance can promote the further development of the digitalization,miniaturization and intelligentization of the instrument.In this paper,16-channel digital control system based on FPGA is designed,and the key technologies are studied.Finally,the detection results of defect are given.The main work and achievements are as follows:1.Study on the core principle of ultrasonic phased array.The theory and detection principle of ultrasonic phased array are studied,including transmitting and receiving,delay control law and error.Meanwhile,the principle and implementation method of scanning method are discussed,as well as the influence factors of system performance.2.The overall design of the digital system.An overall design scheme of digital control system for 16-channel and 64-element ultrasonic phased array detection is proposed,and the main control FPGA is selected and the function module is divided.Overall development of debugging environment and processing skills of cross-clock domain are showed.3.Digital beam formation design.The key technologies of digital beamforming are studied and proposed,including the low-complexity 2.5ns fine emission delay based on 1/4 phase difference,interpolated receiver beam synthesis algorithm based on CIC filter,and the digital control of the chip AD9216.The experiment shows that the design can achieve 2.5ns high delay precision of beam formation in the case of less resource consumption.4.High-speed data store and communication design.This paper studies and designs the key technologies of high speed real-time data store and communication,including transmission controller based on USB3.0 and storage controller based on DDRII.The experiment proves that the scheme achieves high-speed storage and transmission.5.Online testing of digital systems.On the basis of testing the various modules of the digital system,the whole ultrasonic system is combined to give the detection of line sweep and fan scan for the defect of standard B-type block.The test proves that the digital system has achieved predetermined functions and indicators.