2D measurement system scales and peculiarities of their calibration

Abstract

Nowadays new and more informative 2D linear displacement measurement systems are being designed. Usually they provide information about value and direction of linear displacement, absolute position as well as small linear displacement of moving node, perpendicular to the main motion and small angular deviations about the axis, perpen-dicular to the plane of encoder scale. While using these systems, it is possible to assess and compensate linear and angular errors of linear motions in the plane. The prototype of 2D scale is briefly described. The distinguishing feature of these scales is raster elements of different width, arranged in different distances at an angle in respect of scale axis as well as periodic raster structure, formed perpendicular to scale axis and composed from long raster elements of equal width. Calibration peculiarities of aforementioned scales are analyzed. Their essential difference, while comparing with common rasters of periodic and code structure, is that in the researched case 2D, i.e., measurement in plane, and not one-dimensional problem is being solved. Calibration results of prototype of 2D scale are presented.