投影图像法对旋转体空间扫描角和转速的测量研究

扫描角和转速是某伞弹系统风洞试验中要求必须测量的重要技术参数。对伞-弹系统扫描角和转速进行定量动态测量是试验中必不可少的技术环节。投影图像法测量的原理就是利用一定截面积的两路正交平行光源，将旋转弹体分别投影到两个正交的投影屏上，利用两套高速CCD成像系统，将两路弹体投影图像同步采集并实时记录下来，试验结束后利用图像处理软件自动计算出两路图像序列角度分量，按照时序合成出每一时刻弹体的空间扫描角，并根据序列角度分量，计算出弹体的瞬时转速和全周期平均转速。利用该测量方法，在西安某所立式风洞中成功对多个型号的伞弹旋转弹体空间扫描角和弹体转速进行了测量，取得了良好的测量结果。旋转体的静态角度测量精度为0．18°，动态扫描角测量精度控制在0．25°以内。作者从扫描角测量原理和方法入手，着重介绍该投影图像处理测量系统的设计和实际运用，给出了某伞-弹系统风洞试验的测量结果。

Orthogonal projection method for rotator＇s spatial sweep angle and rotating speed measurement

Abstract：Sweeping angle and rotating speed are important parameters of a parachute-ball rotator in wind tunnel measurement experiment as well as a necessary quantitative dynamic measurement test. The prineiple of the orthogonal projection method is to use a two-way orthogonal parallel light source of a given cross-section area to project the rotator into two orthogonal sereens, two high-speed cameras synchronically record the projecting images. The image processing software automatically calculates the angularity of two-way image sequence, sequentially photographs every moment＇s spatial sweep angle, and according to the sequential angularity, the instantaneous rotating speed and average rotating speed of all cyele can be calculated. Applying the orthogonal projection method, we have successfully measured different types of parachute-ball rotator in a vertical wind tunnel in Xi＇an and obtained good results. The static angle measurement accuracy is 0.18°, the dynamic sweeping angle measurement accuracy is limited in 0.25°. This paper describes the principle and structure of the orthogonal projection method as well as the application of the image processing system, and the wind tunnel measurement results were also given.