非接触位移测量中参考点抖动影响的补偿方法

针对用非接触3D光学位移测试系统进行结构动位移形变测试时，测试参考点会发生抖动而影响测试结果的现实难题，提出在用光学位移测试系统测试结构动位移的同时，利用3D加速度传感器同步测试参考点的振动加速度进而获得参考点的3D振动位移，然后用参考点的3D振动位移去修正光学位移测试系统的测量结果，从而提高测量精度的测试和处理方法。论文重点对如何通过振动加速度获得准确的参考点3D振动位移和如何通过参考点的3D振动位移来修正3D光学位移测试系统测量输出的方法和算法进行了研究、仿真和实际测试验证。仿真和实验结果表明，本文提出的测试方法和算法可以有效补偿动位移直接测量中因参考点抖动而引入的测量误差，显著提高测量精度。

The Compensation Method for the Effect of the Reference Point′s Jitter in Non-contact Displacement Measurement

During three dimensional vibration displacement measurement based on optical devices, the reference point of the optical measurement system must remain stationary. It is difficult to satisfy this condition in field tests. To solve this problem, a compensation method was presented to amend the influence of small vibrations of the reference point. The displacement of the reference point can be obtained from its acceleration signal at first, and the correction matrixes for target displacement are derived for compensating the measurement errors caused by the shaking of the reference point. The data processing algorithm to convert acceleration signal to displacement signal is presented, and the effectiveness of this algorithm is verified by simulation of composite sinusoidal signals and damped decaying vibration signals with random white noise. The theory and calculation procedure for correction matrixes derived from displacement of the reference point are comprehensively discussed. The experimental measurement system was built using two sets of NDI Optotrak Certus System and one 3D capacitive accelerometer, which is used to verify the theory and method proposed in the paper. Measurement results with data processing show that this method can effectively compensate and correct the measurement errors due to vibrations of the reference point, thus improved measurement accuracy is expected.