Fundamentals of a new absolute magnetic scale using nonrepeated codes

Abstract

For the linear displacement measurement in industrial machines, a linear scale using a magnetic phenomenon is superior to environment-resistance. An absolute-type magnetic scale has the feature of providing safety of a position information with high reliability. Until now, an absolute-type magnetic scale writes a position information at plural parallel tracks. The scale becomes large-sized for a long measuring length. Furthermore, a fine magnetic pattern of the scale is needed for a high resolution. From the practical viewpoint, however, the fine pattern makes the clearance of detecting head and scale small. For the solution of these problems, a new magnetic scale is proposed where an absolute position information is written at series on one track accompanying a parallel incremental track. The scale is expected to be small-sized and to show a high efficiency having a long measurement range without decreasing accuracy and resolution. from the above, the new absolute-type magnetic scale with absolute track is made where the position-information is written in at series by using nonrepeated codes and with a parallel incremental track.Furthermore, the operation and structure, performance characteristic are clarified. The operation characteristics of the scale are measured, and the response speed and the position accuracy are discussed.