Position measuring device

Patent metadata

Field	Value
Publication number	US-2022282999-A1
Application number	US-202017634559-A
Country	US
Kind code	A1
Filing date	Jul 8, 2020
Priority date	Sep 4, 2019
Publication date	Sep 8, 2022
Grant date	—

Abstract

A position-measuring device includes a carrier body having a first and second measuring graduations and a reference mark. The first and second measuring graduations include graduation structures periodically arranged along first and second measurement directions, respectively, that are perpendicular to each other. The graduation structures of the first measuring graduation each extend parallel to a first direction and the reference mark extends in a second direction that forms an angle different from 0° with the first direction. First and second scanners are configured to scan the first and second measuring graduations and generate first and second scanning signals, respectively. A third scanner is configured to scan the reference mark and generate a reference pulse. The position-measuring device is configured such that a phase angle of the reference pulse is determined as a function of the first scanning signals and the reference pulse.

First claim

1 : A position-measuring device comprising:
a carrier body having a first measuring graduation, a second measuring graduation, and a reference mark, the first measuring graduation including a plurality of graduation structures periodically arranged along a first measurement direction, the graduation structures of the first measuring graduation each extending parallel to a first direction, the second measuring graduation including a plurality of graduation structures periodically arranged along a second measurement direction, the first measurement direction and the second measurement direction being perpendicular to each other, and the reference mark extending in a second direction, the first direction and the second direction forming an angle different from 0° therebetween, a first scanner configured to scan the first measuring graduation and generate first scanning signals; a second scanner configured to scan the second measuring graduation and generate second scanning signals; and a third scanner configured to scan the reference mark and generate a reference pulse, wherein the position-measuring device is configured such that a phase angle of the reference pulse is determined as a function of the first scanning signals and the reference pulse.

2 : The position-measuring device as recited in claim 1 , wherein the position-measuring device is configured such that a first absolute position in the second measurement direction is determined as a function of the phase angle of the reference pulse.

3 : The position-measuring device as recited in claim 2 , wherein the position-measuring device is configured such that the first absolute position in the second measurement direction is determined utilizing a predetermined association rule for associating the phase angle of the reference pulse with the first absolute position in the second measurement direction.

4 : The position-measuring device as recited in claim 2 , wherein the position-measuring device is configured such that the first absolute position in the second measurement direction is determined utilizing a predetermined conversion factor.

5 : The position-measuring device as recited in claim 1 , wherein the position-measuring device is configured such that the phase angle of the reference pulse is determined as a function of a phase signal derived from the first scanning signals.

6 : The position-measuring device as recited in claim 2 , wherein the position-measuring device is configured such that a second absolute position in the second measurement direction is determined as a function of the phase angle of the reference pulse and the second scanning signals.

7 : The position-measuring device as recited in claim 6 , wherein the position-measuring device is configured such that the determination of the first absolute position in the second measurement direction is performed with a first resolution, and that the determination of the second absolute position in the second measurement direction is performed with a second resolution, the first resolution being lower than the second resolution.

8 : The position-measuring device as recited in claim 6 , wherein the position-measuring device is configured such that the second absolute position in the second measurement direction is determined as a function of a phase signal derived from the second scanning signals.

9 : The position-measuring device as recited in claim 6 , wherein the position-measuring device is configured such that a relative position in the second measurement direction is determined as a function of the second scanning signals, and such that the relative position in the second measurement direction is combined with the first absolute position in the second measurement direction to obtain the second absolute position in the second measurement direction.

10 : The position-measuring device as recited in claim 1 , wherein the phase angle of the reference pulse is defined relative to a reference phase angle determined by the first scanning signals and is in a range of −90° to +90°.

11 : The position-measuring device as recited in claim 1 , wherein the phase angle of the reference pulse is in a range defined by a first threshold and a second threshold, wherein the first threshold is associated with a minimum of a first absolute position to be determined in the second measurement direction as a function of the phase angle of the reference pulse, wherein the second threshold is associated with a maximum of the first absolute position to be determined in the second measurement direction, wherein the minimum and the maximum define a permissible range for the determination of the first absolute position in the second measurement direction, wherein the permissible range corresponds to a number of signal periods of the second scanning signals, and wherein the number of signal periods is in a range of 2 to 10.

12 : The position-measuring device as recited in claim 1 , wherein the phase angle of the reference pulse is given by a linear relationship that is defined by a slope, the slope being at least 5° per signal period of the second scanning signals.

13 : The position-measuring device as recited in claim 1 , wherein a width of the reference pulse in relation to the first scanning signals is in a range of 180° to 540°.

14 : The position-measuring device as recited in claim 1 , wherein the first direction is perpendicular to the first measurement direction.

15 : The position-measuring device as recited in claim 1 , wherein the graduation structures of the second measuring graduation each extend parallel to a third direction, the third direction being perpendicular to the second measurement direction.

16 : The position-measuring device as recited in claim 10 , wherein the phase angle is in a range of −60° to +60°.

17 : The position-measuring device as recited in claim 12 , wherein the slope is 20° or 30° per signal period of the second scanning signals.

18 : The position-measuring device as recited in claim 13 , wherein the width of the reference pulse in relation to the first scanning signals is in a range of 300° to 420°.

19 : A method for operating a position-measuring device comprising a carrier body having a first measuring graduation, a second measuring graduation, and a reference mark, the first measuring graduation including a plurality of graduation structures periodically arranged along a first measurement direction, the graduation structures of the first measuring graduation each extending parallel to a first direction, the second measuring graduation including a plurality of graduation structures periodically arranged along a second measurement direction, the first measurement direction and the second measurement direction being perpendicular to each other, and the reference mark extending in a second direction, the first direction and the second direction forming an angle different from 0° therebetween, the method comprising:
scanning the first measuring graduation and generating first scanning signals;
scanning the second measuring graduation and generating second scanning signals;
scanning the reference mark and generating a reference pulse; and
determining a phase angle of the reference pulse as a function of the first scanning signals and the reference pulse.

Assignees

• Heidenhain Gmbh Dr Johannes

Inventors

• Haible Pascal
• Bartlechner Alois
• Gruber Sebastian

Classifications

• G01D2205/90

  Two-dimensional encoders, i.e. having one or two codes extending in two directions · CPC title

• G01D5/2458 Primary

  with incremental and absolute tracks on separate encoders · CPC title

• G01D5/2457 Primary

  Incremental encoders having reference marks · CPC title

• G01D5/34792

  with only digital scales or both digital and incremental scales · CPC title

• G01D5/34776

  Absolute encoders with analogue or digital scales · CPC title