Photoelectric Reflection Multi-point Speed Measurement Technology For Coil Gun

The electromagnetic coil gun is weaponry that uses a magnetic field to accelerate the launch of armature projectiles with a large volume and fast velocity change of the launch armature.The flight speed of the armature projectile at different positions is the one of key parameters to measure its firing efficiency.Nowadays,the domestic and foreign standard light curtain targets and canopy targets have the disadvantages of considerable size and inconvenience of portability,which cannot be installed on the coil gun test site and are not suitable for multipoint measurement of coil gun projectile velocity.Because of the above problems,the thesis researched a multipoint velocity measurement technology of photoelectric reflection for coil guns.The main research contents are as follows.(1)Overall scheme design.The photoelectric reflection multipoint velocity measurement technology scheme is developed according to the multipoint velocity measurement requirements.The photoelectric reflection multipoint detection device adopts the reflection type testing method,using a line array laser,a point detector and a signal processing circuit to construct a light detection curtain.The multi-channel signal acquisition and processing system processes the multi-channel projectile signal and calculates the multipoint projectile velocity according to the processed data.(2)Design of photoelectric reflective multipoint detection unit.The modular design of the photoelectric reflective multi-detector unit,two photoelectric detector devices placed on both sides of the laser,and a standard line to receive the light energy emitted by the laser.The signal amplification circuit receives the changing electrical signal output from the detector devices and outputs the projectile over-target pulse signal after amplification.Design the optical-mechanical structure to assemble each module and multiple detector units to form a photoelectric reflection multipoint detection device.(3)Design of multiple signal acquisition and processing modules.FPGA is selected as the core of the multiplexed projectile signal acquisition and processing module.The circuit design of the whole module is carried out,including the photoelectric coupling circuit,signal transmission circuit and FPGA circuit.The Verilog HDL language was used to program the design of different functional modules on the FPGA chip,including the clock source module,signal capture module,counting module,data integration module,FIFO storage module,and serial communication module.The upper computer operating platform is used to process the data.(4)Experiment and verification.Experiments were conducted to test the function of each module of the photoelectric reflection multipoint measurement system,including the signal processing circuit,multiplex signal timing and data transmission.The whole photoelectric reflection multipoint measurement system was tested and verified by a single module and joint test of each module,and the speed measurement error was analyzed.The test results show that all modules of the photoelectric reflective multipoint speed measurement system can work normally and meet the design requirements of the whole system.