Research On Vertical Target Coordinate And Velocity Testing System Of LED Large Target

The flying speed of projectile and the coordinate of projectile landing on target are important indexes for performance inspection in the process of weapon production and development.Because of its high accuracy,real-time non-contact and suitable for the test of multiple caliber projectiles,the photoelectric detection technology of light screen target has become the main test technology with obvious advantages in the range test equipment.Aiming at the requirements of limited cross-sectional area,large effective target surface and high measurement accuracy,a large target coordinate and velocity measurement system based on small size LED-PD array is designed in this paper.In this paper,the technologies of light screen target testing,LED array and beam shaping,detection array and aperture system are summarized.A scheme of light screen testing system with large shooting surface composed of LED array-aperture-PD array is proposed.The coordinates of projectile landing on target are measured by two sets of vertical intersecting light screens,and the velocity of projectile is measured by two sets of fixed distance parallel light screens.The system uses small size and high brightness LED seamlessly splicing to form two sets of parallel linear light sources to produce two sets of light curtains.An aperture with staggered through apertures with fixed spacing is designed to restrict the radiation of the LED to form a light curtain subdivision.The two sets of light curtains are confined by multi-layer apertures at the detection end to form a staggered array corresponding to the coordinates of the effective target plane.A high-speed and high-sensitivity photosensitive transistor staggered array is selected to receive the light emitted by the LED,and the change of the light flux of the PD array is extracted when the projectile passes through the target through the adaptive threshold signal conditioning circuit.The signal is converted into a pulse signalwhich is easy to be processed by the digital circuit and transmitted to the data acquisition terminal.The data acquisition system recognizes the signal and displays the coordinate information of the impact point.In this paper,the optical model of LED-PD array system is established,and the influence of LED spacing on the uniformity and distribution of light energy on large target surface is analyzed;the mathematical model of double aperture system is established,and the influence of aperture spacing and diaphragm spacing on the detection system is analyzed,so as to determine the parameters of the aperture system;the sensitivity model of the detection system is established,and the sensitivity distribution of the large LED target screen is analyzed.The sensitivity of the system is tested by optical simulation;the mathematical model is established to analyze the target utilization ratio of the test scheme;the driving circuit of the LED array and the adaptive threshold signal conditioning circuit are designed to realize the uniform luminescence of the LED array and the response of the LD array to the projectile at any coordinate point in the effective target plane;the feasibility of the system scheme is verified by building a one-dimensional light screen system,and the error analysis of the projectile coordinate and velocity test is carried out.By theoretical analysis and experimental verification,the feasibility of large target test system for LED-PD arrays is proved.