Design Of Handheld Ultrasonic Inspection Hardware Systems

With the increasing maturity of ultrasonic detection theory and the rapid development of modern large scale integrated circuit and computer technology, ultrasonic testing technology with its celerity, accuracy, high efficiency, pollution-free, low cost etc, is widely used in machinery manufacturing, petrochemical, aviation aerospace and other industrial sectors, as an important means to ensure project quality and the safety of equipment. In recent years, ultrasonic flaw detection system is developing towards to high speed, digital, automation, and intelligence, portable, low-power products are becoming a big demand for testing operations.This thesis aims to develop a hand-held ultrasonic testing system based on embedded platform, and therefore, the main focus of our design is miniaturization, low power consumption and high performance. Now main tasks are summarized as follows:Firstly, propose and implement the design of a hand-held ultrasonic detection hardware platform based on ARM & FPGA. ARM processor, because of its low power consumption and high performance, acts as the core of computing and control of the whole platform through the relocation of Linux operating system. FPGA is responsible for echo signal pre-processing and systems'synchronization timing control.Secondly, through Verilog programming, successfully complete the simulation and verification of the system's key technology, such as digital demodulation, non-uniform maximum extraction and hardware gate alarm, and well solve the problem of low refreshing rate, slow scanning and poor reliability of traditional instruments, and facilitate the following high-speed data stream processing. Thirdly, propose and implement the gain control signal processing circuit based on the chip AD8331, and satisfy the design requirement of low noise, wide bandwidth, high gain and so on. Through the band-pass filter design, out-of band noise is suppressed effectively and the system signal-to-noise ratio is improved conspicuously.Fouthly, to achieve the low power consumption design, we adopt the new power supply program with boosting DC-DC converter and LDO regulator, not only to meet higher conversion efficiency, but also improve the stability of power supply; make full use of ARM system's power management features to achieve the overall system power controllability; take the static and dynamic current consumption of FPGA into consideration, in order to achieve low power consumption design; choose the LCD of small size and low power, and achieve brightness adjustment through PWM backlight, and so on.Finally, to achieve the miniaturization design, use SMD package and highly integrated processing chip as much as possible to effectively reduce the layout area; at the same time, external interface should apply miniaturization design, and debuging interfaces use portable pluging-in connector instead.Now, the first edition of the hardware platform has been designed successfully and passed related function and performance testing, the preliminary requirements have been met well.