基于单目红外的远距离多测点振动测量方法

Study on the remote multi-points vibration measurement method based on single infrared camera

为解决基于视觉方法测量柔性结构模态测量范围小、无法同时测量大型柔性结构纵深方向多个节点的振动情况的问题,提出基于单目红外的远距离多测点振动测量方法。在单红外相机的基础上,加装带通滤光片、红外LED等设备构成测量系统。利用离焦成像的原理对不同距离段内的LED灯组同时成像,对测量结果使用卡尔曼滤波平滑减小误差,滤波后定位精度为0.5 mm,重复性定位精度优于0.2 mm。通过在不同距离布设不锈钢尺模拟大型柔性结构,测量及实验计算结果与固有频率理论值进行比较相对误差最小为2.22%,计算过程中,滤波后数据有效地排除了干扰峰值。实验结果表明,所提测量方法简单有效,可应用于大型柔性结构模态检测等领域。

To measure the flexible structure modal, the visual method has the problem of small measurement range. Besides, the vibration of multiple points in depth direction of a large flexible structure cannot be also measured. To solve these problems, one kind of measuring method based on monocular infrared camera is proposed. On the basis of single camera, the system is consisted of a pass filter, infrared LED, etc. The principle of confocal imaging is utilized to take LED images of different distance at the same time. The error of measurement result is decreased by Kalman filter. In this way, the positioning accuracy is only 0.5 mm and the repetitive positioning accuracy is better than 0.2 mm. By setting stainless steel rulers in different distance as the simulated large flexible structure, the first order frequency of steel ruler is obtained by modal analysis. The relative error of the theoretical value is 2.22%. During the calculation process, the interference peak can be effectively eliminated by the filter. Experimental results show that the proposed method is simple and effective and can be applied to the large-scale flexible structure modal detection.