Fast shape and position control by Moire-filtering and object-adapted fringe projection

摘要

An all-optical method for shape and position control is presented. We use a combination of object-adapted fringes and Moire-filtering to monitor the exact position of a rotating fan. Object-adapted fringes are projected onto the test object leading to a straight periodic grid in an intermediate image plane. A Ronchi ruling is inserted to block these straight fringes. If the test object is in a misaligned position, the filtering by the grating is incomplete and a signal can be measured behind the grating. We used this method to monitor a fan with seven wings rotating with 100 Hz and to detect a shape defect of a single wing with 500 measurements per second.