Data Recorder Designed For Measuring Speed Of Premade Fragments On Site Based On Laser Screen

In the static explosion experiment of fragment warhead, testing the velocity of premade fragment is necessary for measuring the explosive power of warhead. At present, the method based on laser screen for testing the velocity is advanced in China, which could change the optical signal into voltage signal during the fragment flying through laser screen. The voltage signal is the signal as fragment flies across the laser screen. During the field experiment, adopting the method of NI data acquisition instrument for collecting signal has these shortage of high cost, difficult laying cables and equipment protection. Therefore, in order to acquiring the signal waveform in severe testing experiment, designing a special data recorder for storing signal data is essential, which could calculate the flying speed of premade fragment based on these signal data.The data recorder descript detailed in the paper is able to coordinate work with laser fragment velocimeter, these two parts together make up the measuring system. The system consists of four main parts: the FPGA chip as main controller, A/D convertor for sampling fragment signal, SRAM chip as large capacity data buffer, Flash chip as large capacity data memory cell in the recorder. What’s more, communicating the data of fragment signal waveform with master computer through USB interface and calculating the flying speed of fragment based on the data processing.Taking account the design indexes, explain and analyze the key technology in the design process of data recorder. After using the pipe line scheme, the speed of storing data into Flash chip has been greatly improved and when the management solution of bad data storing blocks adopted, it could insure the correctness and reliability of storing data; To prevent false trigger of testing system, an algorithm is designed for eliminating false trigger, which has been verified correctly.Finally, taking individual test and joint test with laser fragment velocimeter for the data recorder firstly; In addition, presenting the waveform and flying speed of fragment after making ball cartridge experiment. Test shows that the data recorder performed well and has advantage of high precision, easy operation, modularization compared with NI data acquisition instrument.