窗口玻璃畸变校正下的自由飞模型姿态测量技术研究

高超声速风洞试验中,模型的姿态信息是试验数据是否可靠的重要判断依据,其测量精度对试验结果有着重要影响。双目视觉测量系统能测量高超声速风洞自由飞试验模型的姿态参数,通常将其放在风洞试验段外,通过试验段壁上窗口玻璃观测试验段内部的模型。然而,窗口玻璃产生的成像畸变将降低系统的测量精度。为此,本文提出了窗口玻璃成像畸变校正下的自由飞模型姿态测量技术。通过对窗口玻璃折射造成像面畸变进行建模,提出基于标记点线性拟合的校正方法,快速减小成像畸变。在此基础上,在Φ1 m高超声速风洞试验现场搭建了视觉测量系统。试验结果表明:当测量范围为1 m×1 m×1 m时,测量精度优于0.5 mm,并完成了自由飞试验模型六自由度姿态的测量工作,满足气动数据分析的要求。

Research on attitude measurement technology of free flying model under window distortion correction

During hypersonic wind tunnel tests,the pose information of a model supports the reliability of the experimental data,and the measurement accuracy of these data has a significant impact on the test re?sults.Binocular vision measurement systems can measure the attitude parameters of free flight test models in a hypersonic wind tunnel.The system is usually placed outside of the wind tunnel test section and ob?serves the model through a glass window situated on a wall of the test section.However,the glass win?dow distorts the image and reduces the measurement accuracy.This paper proposes a measurement meth?od to correct the glass window distortion.By modeling the image surface distortion caused by refraction through the glass window,a correction method is proposed based on the linear fitting of marker points to eliminate the image distortion and improve the measurement accuracy.Moreover,a binocular vision mea?surement system is developed at the scene of theΦ1 m hypersonic wind tunnel test,and a six degrees of freedom attitude of a free flight model is successfully measured.The results show that the measuring accu?racy was greater than 0.5 mm when the measuring range was 1 m×1 m×1 m.Therefore,the system satisfies the requirements of subsequent pneumatic data analysis.