风洞试验中模型迎角视觉测量技术研究

Vision Measurement Technology Research for Model Angle of Attack in Wind Tunnel Tests

发展了一种基于双相机的风洞试验模型迎角视觉测量技术。即在风洞模型表面绘制或喷涂一些高对比度的标记点,采用两台400万像素的工业相机采集模型的运动图像,然后求解图像的共线方程获得模型表面标记点的三维空间坐标,利用表面标记点坐标最小二乘拟合出一条空间直线,通过不同时刻空间直线单位方向矢量的变化计算出模型的迎角变化。利用精密电子倾斜仪对迎角视觉测量系统进行静态标定,结果表明:迎角视觉测量系统的准确度在0.01°以内。迎角视觉测量系统在2m超声速风洞中对一尾支撑无主测力天平铰链力矩测量模型的实时迎角进行了测量,结果表明:系统具有很好的响应特性,可以作为风洞试验中迎角测量的一种有效方法,尤其是用于无主测力天平时模型真实迎角和支杆弹性角的测量。

A vision measuring technique based on two cameras is developed to measure model angles of attack in wind tunnel tests.Two high-speed industrial cameras with 4 million pixels are used to capture the motion images of the tested model,on the surface of which some high contrast targets are painted.Then the three-dimensional coordinates of the targets are acquired by the solution of the imaging collinear equations.The changes of angle of attack are calculated through the change of the unit vectors of the space lines fitted by the three-dimensional coordinates of the targets.Static validation results on the angle of attack vision measurement system by sophisticated electronic clinometer indicate that the accuracy of the angle of attack vision measurement system is within 0.01°.Dynamic test results on a hinge moment measuring model which is fixed on a sting without main load balance in a 2 m supersonic wind tunnel indicate that the measurement system has good response characteristics and can be used as an effective method for measurement of angle of attack in a high speed wind tunnel,especially for measurement of accurate angle of attack of models and sting elastic angle with the absence of a main load balance.