SYSTEMS AND METHODS FOR APPLYING GRID LINES TO A SHAFT AND SENSING MOVEMENT THEREOF

摘要

Methods for precisely applying finely spaced grid lines (114) to an existing shaft (112) on site include, in a first embodiment, attachment of a master grid line carrier (607) to the shaft (112). In preferred embodiments, the carrier (607) is helically wrapped about the shaft (112) or mated at a diagonal seam across the carrier (607). Photosensitive material is then applied to the shaft (112) at one or more axial locations. The shaft (112) is rotated and passage of the grid lines (114) on the master is sensed by an optical sensor (104). A light source (624) synchronized to the detection of the master grid lines (114) exposes the photosensitive material as the shaft (112) is rotated to create identical sets of finely spaced grid lines at multiple axial locations on the shaft (112). The invention also includes a synchronous laser Doppler velocimeter (SLDV) which accurately senses the passage of the lines on the shaft. An extremely accurate torsional interferometer can be constructed using the SLDVs.