Design Of A New Single Fiber Detonation Velocity Meter Based On FPGA

Detonation velocity is the speed of detonation wave propagation in the explosive, whichis an important indicator to measure the detonation of an explosive performance. It is alsoimportant to measure the detonation in researching unsteady detonation and explosivespreparation. Electrical probes are commonly used to test of detonation velocity in modernexperiment field. The particularity electrical probe is susceptible to electromagneticinterference, which limits the certain application. Using optical fibers as sensors to obtainexplosive signals, an FPGA-based optical detonation velocity instrument is designed toachieve high-precision timing measurement up to 10 nanoseconds.The detailed design of the instrument of the detonation velocity is given in thispaper. Fiber Detonation Velocity Meter consists of fiber probes, photoelectric conversionmodules, trigger modules, target distance input modules, FPGA module, LCD display moduleand other components.The fiber probe acquires the optical radiation signal generated by thedetonation of explosive. After photoelectric conversion and subsequent processing circuit, thetest results are visually displayed on the LCD. FPGA logic circuit consists of a timing module,target distance adjustment module, the composition of the divider module, BCD codeconversion module, look-up table module and LCD driver module.Finally, we discuss the error sources and methods for reducing errors from the testingprocess and instrument design，and give the formula of the instrumental error and relativeerror. We also verify the performance of Fiber Detonation Velocity Meter by on-siteexperiments. The experiments show that the instrument has the features of immunityelectromagnetic interference, stable and reliable, high precision, and easy operation.