基于视觉分区的结构振动模态测试方法

A STRUCTURAL VIBRATION MODAL TESTING METHOD BASED ON VISION SUBAREAS

为提高单目视觉方法进行模态测试的精度,提出了一种可估计分区视场大小及分区数的分区模态测试方法。考虑到低分辨率图像和运动模糊对振动测量精度的影响,建立了测量视场参数与测量精度的关系,通过求解最优的测量视场参数,估计出分区视场大小及分区数量;将整体结构的全局视场进行分区,展开振动模态测试,通过合并分区视场的频响函数获得整体结构的频响函数,采用PolyMAX方法辨识得到结构的模态参数;通过悬臂梁的模态实验,验证了该文所提基于视觉分区的模态测试方法的有效性。结果表明:该文的方法可有效提高振动响应的测量信噪比和模态参数的辨识精度。

To improve the accuracy of the vibration modal test by the vision method,a vision subarea that can estimate the field-of-view and the number of partitions for the subareas is proposed.The relationship between the measurement field-of-view parameters and the measurement accuracy is established considering the effects of low-resolution images and motion blur on the vibration measurement accuracy.The global field-of-view of the overall structure is partitioned to implement the vibration modal test.The frequency response function of the overall structure is obtained by combining the frequency domain data of the subareas,and the modal parameters of the structure are identified by the PolyMAX method.The validity of the proposed modal test method based on vision subareas is verified through the modal experiment of cantilever beams.The results show that the proposed approach can improve the signal-to-noise ratio of vibration response measurement and the identification accuracy of the modal parameters.