Position sensing

• US 8,181,493 B2
• Filed: 07/27/2006
• Issued: 05/22/2012
• Est. Priority Date: 07/27/2005
• Status: Expired due to Fees

• Current Assignee: NCT Engineering GmbH (Ncte AG)
• Original Assignee: NCT Engineering GmbH (Ncte AG)
• Inventors: May, Lutz
• Primary Examiner(s): Chaudhry, Saeed T
• Application Number:
  US11/994,607
• Publication Number:
  US 20090217711A1
• Time in Patent Office: 2,126 Days
• Field of Search: 68/120.2, 68/120.4, 68/120.6, 68/24, 68/58, 324/251, 324/207, 735/143.1, 735/141.6, 735/143.9
• US Class Current: 68/12.27
• CPC Class Codes: G01D 2205/95 Three-dimensional encoders, i.e. having codes extending in three directions
• CPC Class Codes: G01D 5/145 influenced by the relative movement between the Hall device and magnetic fields see G01R33/06

Abstract

A three-axis linear position sensor apparatus may include (a) a reference device adapted as a magnetic field generating element, (b) a receiver pad adapted to measure a magnetic field generated by the reference device, and (c) a signal-conditioning and signal-processing electronics adapted to determine a three-axis linear position of the reference device based on the magnetic field measured by the receiver pad.

Claims

1. A position sensor apparatus, comprising:

a reference device including a magnetic field generating element;

a receiver pad measuring a magnetic field generated by the reference device; and

a signal-conditioning and signal-processing electronics determining a position of the reference device as a function of the magnetic field, wherein the electronics is operable in (a) a first operation mode in which the electronics is sensitive to a first volumetric space with a first sensitivity and (b) a second operation mode in which the electronics is sensitive to a second volumetric space with a second sensitivity, and wherein the first volumetric space is larger than the second volumetric space, the first sensitivity being smaller than the second sensitivity.

2. The sensor apparatus of claim 1, further comprising:

a user input/output interface enabling a user to operate the sensor apparatus.

3. The sensor apparatus of claim 2, wherein the receiver pad, the electronics and the user input/output interface are situated in a common casing.

4. The sensor apparatus of claim 1, wherein the sensor is adapted for one of a consumer industrial application and an automotive application.

5. The sensor apparatus of claim 1, wherein the reference device includes a magnetic field generating coil.

6. The sensor apparatus of claim 1, wherein the magnetic field generating coil is a spherically wound coil.

7. The sensor apparatus of claim 5, wherein the reference device includes a permanent magnetic element.

8. The sensor apparatus of claim 1, wherein the reference device includes a longitudinally magnetized region of a magnetizable object.

9. The sensor apparatus of claim 1, wherein the reference device includes a circumferentially magnetized region of a magnetizable object.

10. The sensor apparatus of claim 9, wherein the circumferentially magnetized region is formed by a first magnetic flow region oriented in a first direction and a second magnetic flow region oriented in a second direction, the first direction being opposite to the second direction.

11. The sensor apparatus of claim 10, wherein, in a cross-sectional view of the magnetizable object, there are (a) a first circular magnetic flow having the first direction and a first radius and (b) a second circular magnetic flow having the second direction and a second radius, the first radius being larger than the second radius.

12. The sensor apparatus of claim 9, wherein the circumferentially magnetized region is manufactured in accordance with the following manufacturing steps:

applying a first current pulse to the magnetizable object in a such a manner that there is a first current flow in a first direction along a longitudinal axis of the magnetizable object, the first current pulse being such that the application of the current pulse generates a magnetized region in the magnetizable object.

13. The sensor apparatus of claim 12, wherein a second current pulse is applied to the magnetizable object in such manner that there is a second current flow in a second direction along the longitudinal axis of the magnetizable object.

14. The sensor apparatus of claim 13, wherein each of the first and second current pulses has a raising edge and a falling edge, the raising edge being steeper than the falling edge.

15. The sensor apparatus of claim 13, wherein the first direction is opposite to the second direction.

16. The sensor apparatus of claim 1, wherein the receiver pad includes a plurality of magnetic field detection units.

17. The sensor apparatus of claim 1, wherein the receiver pad includes a plurality of magnetic field detection units, the units being symmetrically arranged.

18. The sensor apparatus of claim 1, wherein the receiver pad includes at least one of a group consisting of a coil;

a Hall-effect probe;

a Giant Magnetic Resonance magnetic field sensor; and

a Magnetic Resonance magnetic field sensor.

19. The sensor apparatus of claim 1, wherein the receiver pad includes a plurality of tiltable coils.

20. The sensor apparatus of claim 1, wherein the receiver pad includes a plurality of coils having a non-concentric winding.

21. The sensor apparatus of claim 1, wherein the receiver pad includes four coils having an essentially circular cross-section and having centers arranged on corners of a square.

22. The sensor apparatus of claim 1, wherein the signal-conditioning and signal-processing electronics is coupled to at least one of the reference device and the receiver pad in at least one of a wireless manner and a wired manner.

23. The sensor apparatus of claim 1, wherein the receiver pad and the reference device are positioned essentially parallel to one another.

24. The sensor apparatus of claim 1, wherein the sensor determines at least one of a one-dimensional position, a two-dimensional position, and a three-dimensional position of the reference device as a function of the magnetic field measured by the receiver pad.

25. The sensor apparatus of claim 1, wherein the sensor is a three-axis linear position sensor apparatus, wherein the electronics determines a three-axis linear position of the reference device as a function of the magnetic field measured by the receiver pad.

26. A washing machine, comprising:

the position sensor apparatus of claim 1.

27. The washing machine of claim 26, further comprising:

a rotatable drum, wherein the reference device is attached to the rotatable drum.

28. The washing machine of claim 26, wherein the position sensor apparatus measures a position indicative of a weight load of the washing machine.

29. A method for sensing a position of a reference device, comprising:

generating a magnetic field by the reference device;

measuring, by a receiver pad, the magnetic field generated by the reference device; and

determining, by a signal-conditioning and signal-processing electronics, the position of the reference device as a function of the magnetic field measured by the receiver pad, wherein the electronics is operable in (a) a first operation mode in which the electronics is sensitive to a first volumetric space with a first sensitivity and (b) a second operation mode in which the electronics is sensitive to a second volumetric space with a second sensitivity, and wherein the first volumetric space is larger than the second volumetric space, the first sensitivity being smaller than the second sensitivity.

30. A position sensor apparatus, comprising:

a reference device including a magnetic field generating element;

a receiver pad measuring a magnetic field generated by the reference device;

a signal-conditioning and signal-processing electronics determining a position of the reference device as a function of the magnetic field; and

an off-range indicator indicating an operation state in which the reference device is placed outside of a predetermined measurement spacing.

31. A washing machine, comprising:

a position sensor apparatus of claim 30.

32. A method for sensing a position of a reference device, comprising:

generating a magnetic field by the reference device;

measuring, by a receiver pad, the magnetic field generated by the reference device;

determining, by a signal-conditioning and signal-processing electronics, the position of the reference device as a function of the magnetic field measured by the receiver pad; and

indicating, using an off-range indictor, an operation state in which the reference device is placed outside of a predetermined measurement spacing.