FPGA-based multipoint shock wave measurement system using LDVs for aerospace applications

Abstract

Pyrotechnic devices are widely used in aerospace industry for variety of applications in launch vehicles, payload designs and spacecraft architectures. These devices are used to release, activate and separate structural subsystems. Ignition of these explosive carriers generates high intensity shock waves having immense drawback of cause damage to the sensitive electronic equipment due to its high frequency. Numerous experimental simulation techniques have been developed to study and characterize the behavior of pyroshock on the host structure. In this study, Field Programmable Gate Array (FPGA) based shock wave measurement system was developed using multiple Laser Doppler Vibrometers (LDVs). These LDVs simultaneously capture the shock wave at different locations generated due to explosive based pyrotechnical event. An indigenously developed Graphical User Interface (GUI) was used to visualize the voltage and acceleration plots for each channel. This paper describes the system design, integration and implementation of data acquisition system for multipoint sensing on Xilinx Virtex-6 FPGA based development hardware. Experimental setup was configured to test the reliability of the system. Mechanical shock wave was generated on the aluminum plate using a gun firing 6-mm plastic bullets. The shock wave was captured using three LDVs at various points connected to multichannel data acquisition hardware. This test was used to mimic the pyroshock wave and justify the potential of our system for real pyroshock measurement. Pyroshock generation is dangerous and expensive trial having low chances of repeating the experiment. Therefore, this technology has the advantage of measuring remotely shock response on various locations at the same time.