A Video Signal Processing Technique for Vibration Measurement of a Flexible Beam

Abstract

A video system is used as a single contactless multipoint displacement sensor to measure the vibration displacement of a beam. In this article, several schemes are proposed to reduce the image processing time and to increase its accuracy. The vibration displacements of the entire beam are measured with a sampling rate of 60 Hz. From these measured data, the mode shapes and vibration states can be calculated. The video system is shown to have a potential for on-line control and on-line identification of flexible beam systems.

A vision-based vibration sensing and active control for a piezoelectric flexible cantilever plate

“…First, the searching range is limited around the center position of the previous sampling. A tracking technique is used to reduce the quantity of image data (Tang and Lu, 1992). A ROI image is suitably chosen.…”

“…To decrease the time for image processing, a tracking method is used. Given a maximum vibration speed of interest, the maximum displacement change between two samples can be analyzed (Tang and Lu, 1992). Calculating the center position of the endface of the free side in ROI, then the center position of the free side in the whole imagine will be obtained by referring the position of ROI in the whole image.…”

“…Both resonant frequencies and mode shapes of a vibrating piezoceramic plate can be obtained simultaneously. A video system was proposed as a contactless multipoint displacement sensor for beam vibration measurement (Tang and Lu, 1992). End edge feedback vibration control of a flexible manipulator was also investigated (Qiu et al, 2012).…”

Image sequences and wavelets for vibration analysis: Part 1: Edge detection and extraction of natural frequencies

“…To the authors' knowledge the most recent attempt has been by K uttenkeuler [16], who employed marker-based optical measurements to investigate utter modeshapes in an aeroelastic wind-tunnel. An earlier attempt uses a common video camera to measure the modeshapes of a exible beam [17]. H owever, no further efforts have been made regarding global vibration and/or modal analysis of the structure, according to the authors' knowledge.…”

Mechatronic Design of Flexible Manipulators

“…This ailowed well-understood methods to be used to build the manipu lator system. Simulation work was aJso presented, cis Tang and Lu [94] These studies did control-intensive work to improve beam performance. But they ignored the impact applied from the beam mechanic shape.…”