Cost-effective optoelectronic system to measure the projectile velocity in high-velocity impact testing of aircraft and spacecraft structural elements

Abstract

Abstract. We present a microcontrolled optoelectronic system to measure online the average velocity of a projectile impacting on aircraft and spacecraft structures. The projectile velocity can vary in the range from subsonic to supersonic. The implemented optical system is based on three optical barriers that are crossed by the projectiles before impacting on the structural elements. A simple optoelectronic prototype is constructed and tested. The flight times among the three optical barriers are obtained by the microcontroller system. The measured velocity accuracy in test conditions is better than 1%. A high-brightness liquid crystal display is used to show messages of the system configuration and also the measured projectile velocity. To ensure safety in the experimental impact tests, serial RS-232 communication can be used to monitor this information using a remote computer. The system is highly robust since it is able to measure projectile velocity even when an optical barrier is missed by failure in either the optical transmitter or the receptor.

Velocity vector (3D) measurement for spherical objects using an electro-optical device

“…To activate the second detector (#2) the object must travel de distance d. This distance is vt 12 , where t 12 is the time difference between the activation of two consecutive detectors and v the velocity in the direction of the movement. The velocity in the movement direction is given by (6) where d diam is the diameter of the object and t max is the maximum time a detector is activated and corresponds, because of the symetry of the object, to the diameter.…”

“…For small objects or in the case that it is not possible to install a measurement device on it, external procedures are required to measure the required parameters. There are several non contact measurement methods, some based on image processing [1,2], using doppler-radar devices [3,4,5] or any type of electro-optical device configured as optical barriers [6,7,8]. The methods based on image processing use high speed cameras to record the movement and extract the information of the time used by the object to fly across a known distance and then, the velocity is calculated.…”

Model-based Estimation for Pose, Velocity of Projectile from Stereo Linear Array Image

“…These parameters have major influence on the weapon performance and accuracy. Until recently, many optoelectronic-based [2][3], image-based methods [4][5][6][7][8][9][10][11][12], etc., have been employed to perform this task. Because of the relatively high quality resolution images that the advanced vision systems could provide, and maturity of the image processing algorithms, image-based methods have many benefits against alternative methods.…”

Sistema electro-óptico para la medida de los coeficientes aerodinámicos de objetos esféricos en movimiento

“…En cuanto a las técnicas más común-mente empleadas, independientemente de la aplicación o tipo de proyectil, son las que se basan en tratamiento de imágenes [GC09,BCP05], medida mediante efecto doppler usando radares [AC89, TH81,MDS03] o mediante sensores electro-ópticos en forma de cortinas ópticas [SPMFZ07,KVB09,RM94].…”

“…El trabajo de Sánchez-Peña y otros [SPMFZ07] usa tres barreras ópticas en línea. Cada barrera no es más que un haz láser.…”