Field-modulating angular position measuring device and method for operating the same

• US 20070029470A1
• Filed: 07/31/2006
• Published: 02/08/2007
• Est. Priority Date: 08/02/2005
• Status: Active Grant

• Current Assignee: Dr. Johannes Heidenhain GmbH
• Original Assignee: Dr. Johannes Heidenhain GmbH
• Inventors: Bielski, Steffen, Schroter, Andrea
• Granted Patent: US 7,470,890 B2
• Time in Patent Office: Days
• US Class Current: 250/231.130
• CPC Class Codes: G01D 18/001 Calibrating encoders
• CPC Class Codes: G01D 2205/60 Means for precisely aligning or centering the disk of a rotary encoder, e.g. fitting jigs
• CPC Class Codes: G01D 5/24442 by mounting means
• CPC Class Codes: G01D 5/24485 using other sensors
• CPC Class Codes: G01D 5/2449 using hard-stored calibration data
• CPC Class Codes: G01D 5/34738 Axles; Driving or coupling means

Abstract

A field-modulating angular position measuring device includes a scanning device, a measuring graduation, and evaluation electronics, the scanning device and the measuring graduation being arranged at a scanning distance rotatably relative to each other, and angle-dependent output signals being producible by the scanning device, which may be processed further in the evaluation electronics. The angular position measuring device furthermore has a unit for determining the signal amplitudes of the output signals. The angular position measuring device furthermore includes a temperature sensor, which is able to determine a temperature in the angular position measuring device. The angular position measuring device is configured such that the scanning distance may be determined on the basis of the temperature and the signal amplitudes. Furthermore, a method for operating such an angular position measuring device makes it possible, e.g., to determine a change in length of a shaft.

Claims

1. A field-modulating angular position measuring device, comprising:

a scanning device adapted to produce angle-dependent output signals;

a measuring graduation, the scanning device and the measuring graduation arranged rotatably with respect to each other at a scanning distance;

evaluation electronics adapted to process the output signals;

a unit adapted to determine signal amplitudes of the output signals; and

a temperature sensor adapted to determine a temperature in the angular position measuring device, the scanning distance determinable in accordance with the temperature and the signal amplitudes.

2. The field-modulating angular position measuring device according to claim 1, wherein the unit is associated with a regulator unit adapted to regulate the signal amplitudes of the output signals in accordance with an actuating variable to not exceed a specified deviation from a setpoint amplitude value.

3. The field-modulating angular position measuring device according to claim 1, further comprising a circuit adapted to determine a relative rotational speed between the scanning device and measuring graduation to determine the scanning distance.

4. The field-modulating angular position measuring device according to claim 1, wherein the evaluation electronics are adapted to determine the scanning distance.

5. The field-modulating angular position measuring device according to claim 1, wherein the evaluation electronics are adapted to determine a digital value for the scanning distance.

6. The field-modulating angular position measuring device according to claim 1, further comprising an interface adapted to transmit a value for the scanning distance to subsequent electronics.

7. The field-modulating angular position measuring device according to claim 1, wherein the evaluation electronics include an ASIC chip.

8. The field-modulating angular position measuring device according to claim 1, wherein the temperature sensor is integrated into the evaluation electronics.

9. The field-modulating angular position measuring device according to claim 8, wherein the evaluation electronics include an ASIC chip, the temperature sensor integrated into the ASIC chip.

10. The field-modulating angular position measuring device according to claim 1, wherein the angular position measuring device is configured such that a shaft, an angle of rotation of which is to be measured, is receivable by the angular position measuring device in an enclosing manner.

11. The field-modulating angular position measuring device according to claim 1, wherein the angular position measuring device is arranged as an inductive angular position measuring device.

12. A method for operating a field-modulating angular position measuring device that includes a scanning device and a measuring graduation rotatable relative to each other, angle-dependent output signals produced in the scanning device, comprising:

(a) determining signal amplitudes of the output signals;

(b) measuring a temperature in the angular position measuring device; and

(c) determining a scanning distance in accordance with the signal amplitudes and the temperature.

13. The method according to claim 12, further comprising:

determining a deviation between the signal amplitudes of the output signals determined in the determining step (a) and a setpoint amplitude value; and

ascertaining an actuating variable as a function of a magnitude of the deviation to maintain the deviation within specified limits, the scanning distance determined in the determining step (c) in accordance with the actuating variable.

14. The method according to claim 12, wherein the field-modulating angular position measuring device is arranged on a shaft, the method further comprising determining a change in length of the shaft for a point on the shaft outside of the angular position measuring device in accordance with the scanning distance.

15. The method according to claim 12, further comprising detecting a relative rotational speed between the scanning device and the measuring graduation, the scanning distance determined in the determining step (c) in accordance with the rotational speed.

16. The method according to claim 12, further comprising simultaneously processing the output signals and measuring the temperature in the measuring step (b) in evaluation electronics.

17. The method according to claim 12, wherein the angular position measuring device is arranged as an inductive angular position measuring device.

18. The method according to claim 12, wherein the scanning device and the measuring graduation are arranged rotatably with respect to each other at the scanning distance, the field-modulating angular position measuring device further including:

evaluation electronics adapted to process the output signals;

a unit adapted to determine the signal amplitudes of the output signals; and

a temperature sensor adapted to determine the temperature in the angular position measuring device, the scanning distance determinable in accordance with the temperature and the signal amplitudes.

19. A field-modulating angular position measuring device, comprising:

scanning means for producing angle-dependent output signals;

measuring graduation means, the scanning means and the measuring graduation means rotatably with respect to each other at a scanning distance;

evaluation means for processing the output signals;

means for determining signal amplitudes of the output signals; and

temperature sensing means for determining a temperature in the angular position measuring device, the scanning distance determinable in accordance with the temperature and the signal amplitudes.