A structured light vision system for out-of-plane vibration frequencies location of a moving web

摘要

In this paper, we address the problem of the detection of out-of-plane web vibrations by means of a single camera and a laser dots pattern device. We have been motivated by the important economical impact of web vibrations phenomena which occur in winding/unwinding systems. Among many sources of disturbances, out-of-plane vibrations of an elastic moving web are well-known to be one of the most limiting factors for the velocity in the web transport industry. The new technique we proposed for the contact-less estimation of out-of-plane web vibration properties and during the winding process is the main contribution of this work. As far as we know, this is the first time a technique is proposed to evaluate the vibrations of a moving web with a camera. Vibration frequencies are estimated from distance variations of a web cross-section with respect to the camera. Experiments have been performed on a winding plant for elastic fabric with a web width of 10 cm. Distances from the web surface to the camera have been estimated all along an image sequence and the most significant frequencies have been extracted from the variations of this signal (forced and free vibrations) and compared to those provided with strain gauges and also with a simple elastic string model, in motion.