Encoder apparatus and position detection method
AssigneeCanon Kabushiki Kaisha
InventorHaruhiko Horiguchi
Life of this patent
Estimating the term…
Abstract
An encoder apparatus includes a detection unit, a scale disposed to oppose the detection unit and relatively rotatable with respect to the detection unit, and a processor configured to process an output signal output from the detection unit to obtain a relative position of the scale with respect to a standard position and thus detect an absolute position of the scale. The processor is configured to execute a setting process in which a position where a deviation amount of the scale in a predetermined direction with respect to a rotation axis is equal to or smaller than a threshold value is set as the standard position, the deviation amount changing in accordance with relative rotation of the scale with respect to the detection unit.
Claims12
An encoder apparatus comprising:
- a detection unit;
- a scale disposed to oppose the detection unit and rotatable with respect to the detection unit;
- and
- a processor configured to process an output signal output from the detection unit to obtain a relative position of the scale with respect to a standard position and thus detect an absolute position of the scale,
- wherein the processor is configured to execute a setting process of setting, as the standard position, a position where a deviation amount of the scale in a predetermined radial direction extending from a rotation axis of the scale is equal to or smaller than a threshold deviation value, the deviation amount changing in accordance with relative rotation of the scale with respect to the axis of rotation of the scale, and
- wherein the processor is configured to set the standard position in the setting process after the scale rotated from a position where the deviation amount is larger than the threshold value to a position where the deviation amount is equal to or smaller than the threshold value.
A position detection method for obtaining an absolute position of a scale that is disposed to oppose a detection unit, is rotatable with respect to the detection unit, and is configured to obtain an output signal output from the detection unit, the position detection method comprising:
- performing a setting process of setting, as a standard position for detecting the absolute position of the scale, a position where a deviation amount of the scale in a predetermined radial direction extending from a rotation axis of the scale is equal to or smaller than a threshold deviation value, the deviation amount changing in accordance with rotation of the scale with respect to the axis of rotation of the scale, after the scale rotated from a position where the deviation amount is larger than the threshold value to a position where the deviation amount is equal to or smaller than the threshold value;
- and
- obtaining the absolute position of the scale by processing the obtained output signal and thus obtaining a relative displacement of the scale with respect to the standard position.
Dependencies are inferred from the claim text.