| 摘要 |
An electronic absolute position encoder is provided having a scale, a detector, and a signal processor configured to determine an absolute position of the detector along the scale. The scale includes a signal modulating scale pattern comprising a periodic pattern component and a gradual pattern variation component. The detector includes N spatial phase sensing elements (e.g., conductive windings) and at least one reference sensing element, which is spaced apart along the measuring axis direction by a distance corresponding to an integer multiple of 360 degrees of spatial phase shift relative to a first one of the N spatial phase sensing elements. A first reference signal from the first reference sensing element and a first signal from the first one of the N spatial phase sensing elements include nominally similar signal contributions from the periodic pattern component, and a difference between the two signals is due to a difference in their signal contributions from the gradual pattern variation component. The difference may be used to determine a scale factor M1 for a gradual signal variation exhibited by the detector signals output from the detector. |
| 主权项 |
1. An electronic absolute position encoder, the electronic absolute position encoder comprising:
a scale comprising a first scale track extending along a measuring axis direction and including a first signal modulating scale pattern comprising a periodic pattern component comprising at least one of a periodic area modulation or a periodic material characteristic modulation as a function of position along the first scale track, and a gradual pattern variation component combined with or superimposed on the periodic pattern component and comprising at least one of a gradual area variation or a gradual material characteristic variation as a function of position over a first range along the first scale track; a detector comprising at least a first set of sensing elements aligned along the first scale track, the first set of sensing elements configured to provide a first set of detector signals which respond to the first signal modulating scale pattern and which are indicative of a position of the detector along the first scale track; and a signal processor configured to determine an absolute position of the detector along the scale based on detector signals provided by the detector, wherein: the first set of sensing elements comprises N spatial phase sensing elements and additionally at least a first reference sensing element, wherein: the N spatial phase sensing elements are configured to provide N respective signals and are at their N respective locations along the measuring axis direction on the detector, with each of the N locations corresponding to sensing a unique Nth spatial phase of the periodic pattern component and a corresponding Nth position along the gradual pattern variation component; the first reference sensing element is located at a first reference location on the detector that is spaced apart along the measuring axis direction by a first reference distance corresponding to an integer multiple of 360 degrees of spatial phase shift relative to a first spatial phase sensing element of the N spatial phase sensing elements which provides a first signal corresponding to a first spatial phase of the periodic pattern component and a first position along the gradual pattern variation component; the first reference sensing element is configured to provide a first reference signal corresponding to the first spatial phase of the periodic pattern component and a corresponding first reference position along the gradual pattern variation component such that the first signal and the first reference signal include nominally similar signal contributions from the periodic pattern component and a difference between the first signal and the first reference signal is due to a difference in their signal contributions from the gradual pattern variation component; and the first signal and the first reference signal are not statically connected to one another and contribute to independent input signals for the signal processor, and the difference between the first signal and the first reference signal due to the first reference distance is a first signal difference indicative of a scale factor M1 for a first gradual signal variation exhibited by the first set of detector signals, wherein the first gradual signal variation is due to the gradual pattern variation component as a function of the position of the detector along the first scale track. |
