C017 Design and Testing of a Four-Probe Sensor Head For a Mosaic Grating Surface Encoder

Abstract

A surface encoder, which can measure the XYZ-directional displacements, has been developed. The XY-directional measurement range depends on the size of the XY-axis scale grating. A mosaic XY-axis scale grating, which consists of multiple XY-axis grating, has been proposed to expand the XY-directional measurement range of the three-axis surface encoder. And multi-probe surface encoder, which has two-probe, for the mosaic scale grating has been proposed. In this paper, an optical sensor head, which has four-probe for the mosaic XY-axis scale grating, was developed and basic experiment was carried out to confirm the feasibility of the proposed method.

Design and testing of a four-probe optical sensor head for three-axis surface encoder with a mosaic scale grating

“…When the mosaic scale grating is applied for the three-axis surface encoder, the XYZ-directional displacement cannot be measured when the probe is on the gaps between the XY-axis scale gratings. Therefore, a multiprobe optical sensor head has been developed [28,29]. As shown in figure 1(b), the four probes are arranged in a square on the mosaic scale grating with certain gaps in the X-and Y-directions among the probes so that at least one probe can be on the XY-axis scale grating.…”

“…To overcome these difficulties, a concept of the three-axis surface encoder with a mosaic scale grating, which consists of multiple XY-axis scale gratings arranged in a matrix, has been proposed so that the mosaic scale grating can be used as an effective large XYaxis scale grating [28]. By using prototypes of optical sensor head, the feasibility of the concept of the multi-probe surface encoder with the mosaic scale grating has been investigated [28,29]. In addition, a method of compensating misalignment errors between the two XY-axis scale gratings in the mosaic scale grating has also been proposed [28].…”