Research On Internal Ballistic Velocity Measurement Method Based On Multi-point Detection Principle

The measurement of the velocity of fragments(projectile)moving in the barrel is of great significance for the development of interior ballistic theory,the study of new types of artillery and light weapons,and the verification of weapons.During the use of the gun,the projectile is driven by the explosion of the propellant in the gun barrel,and its speed only accelerates from zero to the maximum speed of the muzzle in a few milliseconds,kilometers per second.It is very difficult to directly observe and measure the acceleration process of the projectile in the gun barrel.At present,the existing methods for measuring interior ballistic velocity,such as the imaging testing technology for velocity fringes of projectile in the bore,are only in the theoretical research stage;Laser Doppler in bore projectile velocity testing technology is too expensive and difficult to maintain.Therefore,in order to meet the demand of interior ballistic velocity measurement,this paper designs a relatively economical and feasible interior ballistic velocity measurement method to meet the research of interior ballistic fragments motion velocity.In the system designed in this topic,according to different functions,the entire system can be divided into different modules to achieve their functions,including a multipoint detection module for measuring fragment signals in the gun barrel,a core data acquisition module composed of FPGA and analog-to-digital converter,a data cache module composed of FPGA and DDR3,and a data transmission module composed of FPGA and Gigabit Ethernet.After the Functional verification of each module is correct,the interior ballistic velocity measurement system is built to complete the velocity measurement function and data analysis.The main work of this article is as follows:1)Study and demonstrate the overall scheme of the system.Develop an overall plan based on the technical indicators of the project,propose a design concept,calculate the system transmission bandwidth in combination with the functional requirements of the project,analyze the mathematical model of the internal ballistic aerodynamic equation,design a dedicated gun barrel for internal ballistic velocity measurement,and analyze and demonstrate the feasibility of each part of the plan.2)Hardware design and simulation verification of the speed measurement system.According to the functional requirements of the system,the hardware of each module is selected,and the circuit schematic diagrams of the signal detection module and the core acquisition and transmission module are designed using Altium Designer.The PCB of each module is also designed.Conduct simulation verification and functional testing on corresponding modules through Vivado and Wireshark development software.3)Implementation of speed measurement function and data analysis.Build an internal ballistic velocity measurement test platform,test and verify the velocity measurement function of the entire velocity measurement system through host computer software in a laboratory environment,and analyze experimental data.After the Functional verification of speed measurement is correct,complete the on-site live ammunition speed measurement at the shooting range base and sort out and analyze the speed measurement data.The shooting range test uses fragments with a diameter of 6.30 mm and a length of 12 mm for live fire.Based on the measured results,it is shown that the system design can meet the design requirements,providing a new solution for measuring the velocity of fragments in the chamber.