Improving magnetic linear position measurement by field shaping

Abstract

This paper addresses the problem of magnetic linear position detection, a common method used in modern industries to detect linear displacement. There are two common realizations based on 1D and 2D magnetic field measurement. While the 2D method features a higher level of signal stability, precision and measurement range when compared to the 1D counterpart, the latter is still used for its cost-effectiveness. In this work a method is proposed to improve 1D linear position detection by using compounds of magnets to generate the field. With this technique several of the advantages of 2D systems, like improved linearity and air gap stability can be translated to 1D systems. The idea is presented in the context of achieving maximal cost efficiency, thus focusing on compounds constructed of only a small number of magnets. To find the optimal layout, however, becomes a highly complex optimization problem that is formulated in detail. As a proof of principle it is then shown that already a simplified optimization can lead to an excellent improvement of the signal properties.