R. Yañez-Valdez1, R. Alva-Gallegos2, A. Caballero-Ruiz*3, L. Ruiz-Huerta4
1,3,4 Laboratorio de Micromecánica y Mecatrónica, CCADET-UNAM. Circuito exterior S/N, C.P. 04510. Cd. Universitaria, México, D.F. *ricardo.yanez@ccadet.unam.mx.
2 Depto. de Mecatrónica. Universidad Tecnológica del Valle de Toluca. Carretera del departamento del DF. Km 7.5, Ejido de Santa María Atarasquillo, Lerma, Estado de México.
Abstract
Traditionally, the use of ferrite as a core of the linear variable differential transformer (LVDT) is suggested in its designs. Nevertheless, problems related to its brittleness and low tensile strength may be considered as important drawbacks for its use as a core material, especially when its geometry is likely to be modified. This work explores other alternatives related to soft magnetic materials, less used in applications of an LVDT core. By means of a decision matrix, from an assortment of different materials, three alternatives were selected. This proposal provides the identification of those materials with higher qualification values to be used as core material. In order to validate the performance of the selected materials, a prototype of LVDT was designed and fabricated. The design was carried out taking into consideration typical performance specifications. Finally, a comparison of the measurements of sensitivity and linearity of the proposed and traditional materials was made.
]]> Keywords: linear variable differential transformer, soft magnetic materials, position measurement, prototype.
Resumen
Por tradición, se sugiere el uso de ferrita como núcleo en el diseño de dispositivos LVDT (transformador diferencial variable lineal). Problemas relacionados con la fragilidad de este material hacen poco atractiva su implementación, especialmente cuando su geometría se puede ver modificada. Este trabajo explora otras alternativas en los materiales magnéticamente suaves, menos tradicionales en tal aplicación, con base en requerimientos propuestos. Cada requerimiento está ligado a la implementación y desempeño del LVDT. Esta propuesta provee la identificación de aquellos materiales potencialmente viables para ser usados como núcleos. Para estudiar el comportamiento de los materiales seleccionados, se diseñó y construyó un prototipo de LVDT. El dispositivo LVDT fue diseñado considerando especificaciones de desempeño típicas. Con el prototipo construido, se estudiaron los materiales mejor calificados, identificados con el proceso de selección previo y una matriz de decisión. Finalmente, se realizó una comparación en las mediciones de sensibilidad y linealidad de los materiales seleccionados y el material tradicional.
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Acknowledgments
This work was supported by CONACYT grant 60895. Thanks are also due to Dr. José Israel Betancourt-Reyes for providing a piece of Mumetal for preliminary tests.
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