Method and apparatus for detecting the position of a body

• US 6,919,719 B2
• Filed: 01/31/2001
• Issued: 07/19/2005
• Est. Priority Date: 03/17/2000
• Status: Expired due to Fees

• Current Assignee: Festo AG & Company KG (Festo GmbH & Company KG)
• Original Assignee: Festo AG & Co.
• Inventors: Reininger, Thomas
• Primary Examiner(s): PATIDAR, JAY M
• Application Number:
  US10/203,261
• Publication Number:
  US 20030030431A1
• Time in Patent Office: 1,630 Days
• Field of Search: 324/207.12, 324/207.2, 324/207.24, 324/207.25, 338/32.H, 338/32.R
• US Class Current: 324/207.2
• CPC Class Codes: F15B 15/2807 Position switches, i.e. means for sensing of discrete positions only, e.g. limit switches
• CPC Class Codes: G01D 18/00 Testing or calibrating apparatus or arrangements provided for in groups G01D1/00 - G01D15/00
• CPC Class Codes: G01D 5/145 influenced by the relative movement between the Hall device and magnetic fields see G01R33/06

Abstract

A position detecting means comprising a sensor arrangement (14) for producing at least one sensor signal in a fashion dependent on a body (11) moving past said means, the sensor signal or signals continuously changing on such movement past. The at least one sensor signal is compared with at least one reference value in a comparator arrangement (20), control means being provided for electronic setting of the sensor arrangement (14) by changing the reference value and the output signal of the comparator arrangement (20) forms the position signal (P) for detection of a relative position of the body (11) and the sensor arrangement (14). Accordingly it is possible for the arrangement (14) to be mechanically set in a relatively rough manner and fine adjustment may be performed by changing the reference value electronically.

Claims

1. A position detecting means comprising a sensor arrangement for producing at least one sensor signal in a manner dependent on a body moving past the means, the at least one sensor signal changing on such movement past the means, a comparator arrangement comparing the at least one sensor signal with at least one reference value, control means being provided for electronic adjustment of the sensor arrangement by changing the reference value and the output signal of the comparator arrangement forming a position signal (P) for detection of a relative position of the body and the sensor arrangement, wherein the sensor arrangement comprises at least two sensors, whose signals are converted in a signal processing circuit into a signal dependent in a substantially linear fashion on the relative position of the body and the sensor arrangement, and wherein one sensor signal is a sine signal and the other signal is a cosine signal.

2. The position detecting means as set forth in claim 1, wherein the body produces a magnetic field or comprises a magnet for the production of such a magnetic field and that the sensor arrangement comprises at least one magnetic field sensor.

3. The position detection means as set forth in claim 2, wherein the at least one magnetic field sensor includes a Hall effect sensor.

4. The position detecting means as set forth in claim 1, wherein two magnetic field sensors are arranged at an angle of 45 degrees in relation to one another.

5. The position detecting means as set forth in claims 4, wherein as magnetic field sensors two hail effect sensor bridge circuits are provided.

6. The position detecting means as set forth in claim 1, wherein the comparator arrangement comprises at least one window comparator or schmitt trigger, the reference value being variable.

7. The position detecting means as set forth in claim 1, wherein the sensor arrangement comprises several identical sensors or sensor combinations arranged one after the other in the direction of motion, whose signals are compared by at least one corresponding component of the comparator arrangement with reference values, which correspond to the sensor signals at the relative position to be detected.

8. The position detecting means as set forth in claim 1, wherein the control means comprises an electrically settable potentiometer or a signal memory means for the reference value.

9. The position detection means as set forth in claim 8, wherein the control means comprises at least one of a digital counter and a digital memory.

10. The position detecting means as set forth in claim 1, wherein for electronically adjusting the sensor arrangement at least one manual operating element is provided.

11. The position detecting means as set forth in claim 1, wherein the electronic adjustment of the sensor arrangement and/or the setting of the reference value is remotely controlled in at least one of a wired and a wireless fashion.

12. The position detecting means as set forth in claim 1, further comprising an evaluating circuit comprising at least one comparator means which constitutes a subassembly together with the sensor arrangement.

13. The position detecting means as set forth in claim 1, further comprising an evaluating circuit comprising at least one of the comparator arrangement, and the control means integrated in a manner separated in space from the sensor arrangement.

14. The position detection means as set forth in claim 13, wherein the evaluating circuit is in a programmable control unit.

15. The position detecting means as set forth in claim 1, wherein the body is the piston of a piston and cylinder unit and the sensor arrangement is integrated on the cylinder.

16. The position detection means as set forth in claim 15, wherein the sensor arrangement is integrated on the cylinder in a longitudinally sliding manner.

17. The position detection means as set forth in claim 15, wherein the sensor arrangement is in the cylinder.

18. The position detection means as set forth in claim 1, wherein the at least one senor signal changes continuously in response to the body moving past the position detecting means.

19. A position detector, the position detector comprising:

a sensor assembly, the sensor assembly outputting at least one sensor signal in response to a body moving past the sensor, the at least one sensor signal changing in response to the body moving past the sensor, wherein the sensor assembly comprises at least two sensors, the at least two sensors outputting output signals that are converted in a signal processing circuit into a composite signal, the composite signal being dependent in a substantially linear fashion on the relative position of the body with respect to the sensor assembly, and wherein the at least two sensors comprise magnetic field sensors substantially arranged at an angle of 45 degrees with respect to each other;

a comparator, the comparator comparing the at least one sensor signal to at least one reference value, the comparator outputting an output signal representing the comparison; and

a controller, the controller being adapted for electronically adjusting the sensor assembly by changing the at least one reference value, the output signal of the comparator representing a position of the body with respect to the sensor assembly.

20. The position detector as defined in claim 19, wherein the body comprises at least one of a magnetic field and a magnet, the sensor assembly comprising at least one magnetic field sensor.

21. The position detector as defined in claim 20, wherein the at least one magnetic field sensor comprises a Hall effect sensor.

22. The position detector as defined in claim 19, wherein the output signals output from the at least two sensors comprise a sine signal and a cosine signal.

23. The position detector as defined in claim 19 wherein the at least two sensors comprise at least two Hall effect sensor bridge circuits.

24. The position detector as defined in claim 19, wherein the comparator comprises at least one of a window comparator and a Schmitt trigger, the at least one reference value being variable.

25. The position detector as defined in claim 19, wherein the sensor assembly comprises a plurality of substantially similar sensors disposed along a direction of motion, the plurality of substantially similar sensors outputting signals that are compared by at least one corresponding component of the comparator with at least one reference value.

26. The position detector as defined in claim 19, wherein the controller comprises at least one of a potentiometer, a signal memory, a digital counter, and a digital memory that is adapted to store the at least one reference value.

27. The position detector as defined in claim 19, further comprising at least one manual operating element adapted to adjust the controller.

28. The position detector as defined in claim 19, wherein at least one of the controller and the at least one reference value is adapted to be remotely controlled in at least one of a wired and wireless fashion.

29. The position detector as defined in claim 19, further comprising a subassembly, the subassembly comprising an evaluating circuit and the sensor assembly, the evaluating circuit comprising at least one comparator.

30. The position detector as defined in claim 19, further comprising an evaluating circuit, the evaluating circuit comprising at least one of the comparator and the control means, the evaluating circuit being integrated in a manner separate from the sensor assembly.

31. The position detector as defined in claim 19, wherein the body comprises a piston in a cylinder, the sensor assembly being integrated on the cylinder.

32. The position detector as defined in claim 31, wherein the sensor assembly is integrated on the cylinder in a longitudinally sliding manner.

33. The position detector as defined in claim 31, wherein the sensor assembly is integrated in the cylinder.

34. A position detecting means comprising a sensor arrangement for producing at least one sensor signal in a manner dependent on a body moving past the means, the at least one sensor signal changing on such movement past the means, a comparator arrangement comparing the at least one sensor signal with at least one reference value, control means being provided for electronic adjustment of the sensor arrangement by changing the reference value and the output signal of the comparator arrangement forming a position signal (P) for detection of a relative position of the body and the sensor arrangement, wherein the sensor arrangement comprises at least two sensors, whose signals are converted in a signal processing circuit into a signal dependent in a substantially linear fashion on the relative position of the body and the sensor arrangement, wherein one sensor signal is a sine signal and the other signal is a cosine signal, and wherein two magnetic field sensors are arranged at an angle of 45 degrees in relation to one another.

35. A position detector, the position detector comprising:

a sensor assembly, the sensor assembly outputting at least one sensor signal in response to a body moving past the sensor, the at least one sensor signal changing in response to the body moving past the sensor wherein the sensor assembly comprises at least two sensors, the at least two sensors outputting output signals that are converted in a signal processing circuit into a composite signal, the composite signal being dependent in a substantially linear fashion on the relative position of the body with respect to the sensor assembly, wherein the at least two sensors comprise magnetic field sensors substantially arranged at an angle of 45 degrees with respect to each other, and wherein the output signals output from the at least two sensors comprise a sine signal and a cosine signal;

a comparator, the comparator comparing the at least one sensor signal to at least one reference value, the comparator outputting an output signal representing the comparison; and

a controller, the controller being adapted for electronically adjusting the sensor assembly by changing the at least one reference value, the output signal of the comparator representing a position of the body with respect to the sensor assembly.