Absolute position detecting device and method
AssigneeNational Tsing Hua University
InventorsCheng-Yi Lin, Heng-Sheng Hsiao, Sheng-Ching Wang, Tsung-Shune Chin, Cheng-Kuo Sung, Jen-Yuan Chang
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Abstract
An absolute position detecting device and method are provided. The absolute position detecting device utilizes the incremental magnetization on a magnetic encoding ruler with two different pole widths, such that elliptical Lissajous curves may be obtained by magnetoresistive sensors. The absolute position may be obtained by determining the region of the signals on the ellipses read by the magnetoresistive sensors.
Claims16
An absolute encoder, comprising:
- a magnetic encoding ruler, comprising:
- a first magnetic path on which a plurality of first magnetic poles with opposite polarities are successively arranged, wherein a length of each of the plurality of first magnetic poles is a first pole width;
- a second magnetic path, parallel to the first magnetic path, on which a plurality of second magnetic poles with opposite polarities are successively arranged, wherein a length of each of the plurality of second magnetic poles is a second pole width, and the first pole width and the second pole width are different from each other;
- a first magnetoresistive sensor disposed adjacent to the first magnetic path to detect magnetic fields of the first magnetic path and to generate a first magnetoresistive signal;
- and
- a second magnetoresistive sensor disposed adjacent to the second magnetic path to detect magnetic fields of the second magnetic path and to generate a second magnetoresistive signal;
- wherein the absolute encoder is configured to output the first and the second magnetoresistive signals.
An absolute position detecting device adapted to detect an absolute position of an object, comprising:
- a magnetic encoding ruler, comprising:
- a first magnetic path on which a plurality of first magnetic poles with opposite polarities are successively arranged, wherein a length of each of the plurality of first magnetic poles is a first pole width;
- a second magnetic path, parallel to the first magnetic path, on which a plurality of second magnetic poles with opposite polarities are successively arranged, wherein a length of each of the plurality of second magnetic poles is a second pole width, and the first pole width and the second pole width are different from each other;
- a sensor module adhered to the object, comprising:
- a first magnetoresistive sensor disposed adjacent to the first magnetic path to detect magnetic fields of the first magnetic path and configured to generate a first magnetoresistive signal;
- and
- a second magnetoresistive sensor disposed adjacent to the second magnetic path to detect magnetic fields of the second magnetic path and to generate a second magnetoresistive signal;
- a processor electrically connected to the first and the second magnetoresistive sensors to respectively receive the first and the second magnetoresistive signals, wherein when the object moves relative to the magnetic encoding ruler, the processor is configured to generate a first elliptical pattern according to the first magnetoresistive signal, and to generate a second elliptical pattern according to the second magnetoresistive signal, and to calculate the absolute position of the object according to the first and the second elliptical patterns.
Dependencies are inferred from the claim text.