Sensor for simultaneous position and gap measurement

• US 8,222,892 B2
• Filed: 06/27/2008
• Issued: 07/17/2012
• Est. Priority Date: 06/27/2007
• Status: Active Grant

• Current Assignee: Brooks Automation Ltd. (United Kingdom) (Azenta, Inc.)
• Original Assignee: Brooks Automation Incorporated (Azenta, Inc.)
• Inventors: Hosek, Martin, Hofmeister, Christopher
• Primary Examiner(s): PATIDAR, JAY M
• Application Number:
  US12/163,802
• Publication Number:
  US 20090033316A1
• Time in Patent Office: 1,481 Days
• Field of Search: 32420717-20725
• US Class Current: 324/207.18
• CPC Class Codes: G01D 5/2086 by movement of two or more coils with respect to two or more other coils

Abstract

An apparatus including a controller, a transport in communication with the controller having a movable portion and a transport path and a multi-dimensional position measurement device in communication with the controller, the multi-dimensional position measurement device including a plurality of transformers and at least one element attached to the movable portion, wherein the multi-dimensional position measurement device is configured so that a circuit is completed in at least one plurality of transformers as the at least one element passes proximate to the at least one of the plurality of transformers and the controller is configured to calculate a multi-dimensional position of the movable object based on an output of the at least one of the plurality of transformers, wherein the multi-dimensional position includes at least a gap between the movable portion and the plurality of transformers.

Claims

1. An apparatus comprising:

a controller;

a transport in communication with the controller having a movable portion and a transport path; and

a multi-dimensional position measurement device in communication with the controller, the multi-dimensional position measurement device including a plurality of transformers and at least one element attached to the movable portion;

wherein the multi-dimensional position measurement device is configured so that a circuit is completed in at least one of the plurality of transformers as the at least one element passes proximate to the at least one of the plurality of transformers and the controller is configured to simultaneously calculate a multi-dimensional position of the movable object based on an output of the at least one of the plurality of transformers, wherein the multi-dimensional position includes a gap between the movable portion and the plurality of transformers.

2. The apparatus of claim 1, wherein each one of the plurality of transformers includes a primary winding and a secondary winding wrapped around a common core.

3. The apparatus of claim 2, wherein the controller is configured to calculate a multi-dimensional position of the movable object based on a voltage induced in the secondary winding.

4. The apparatus of claim 1, wherein the plurality of transformers are successively arranged along a first axis and a secondary winding of each of the plurality of transformers are connected to voltage busses so that secondary windings of successive transformers have alternating polarities.

5. The apparatus of claim 4, wherein the voltage busses include a first and second voltage bus where secondary windings connected to the first voltage bus produce a first output signal and secondary windings connected to the second voltage bus produce a second signal that is phase shifted from the first signal.

6. The apparatus of claim 5, wherein the controller is configured to determine a position of the movable object along a first axis and second axis based on the first and second output signals.

7. The apparatus of claim 1, wherein the plurality of transformers are arranged along a first axis and a third axis where secondary windings of the plurality of transformers are connected to voltage busses so that secondary windings of successive transformers along the first and third axes have alternating polarities.

8. The apparatus of claim 7, wherein the voltage busses include a first, second, third and fourth voltage bus where secondary windings connected to the first and third voltage busses produce a first and third output signals and secondary windings connected to the second and fourth voltage busses produce a second and fourth output signal where the second output signal is phase shifted from first output signal and the fourth output signal is phase shifted from the third output signal.

9. The apparatus of claim 8, wherein the controller is configured to determine position of the movable object along a first and second axis based on the first and second output signals and to determine a position of the movable object along a third axis based on the third and fourth output signals.

10. The apparatus of claim 9, wherein the controller is configured to simultaneously determine a three dimensional position of the movable object wherein the three dimensional position comprises a planar position and an air gap between the movable object and the plurality of transformers.

11. A position measurement system comprising:

a controller;

a transport in communication with the controller having a movable portion and a transport path; and

a multi-dimensional position measurement device in communication with the controller, the multi-dimensional position measurement device including at least one element attached to the movable portion and a plurality of sensing elements configured to produce an output voltage in response to the at least one element moving in proximity to at least one of the plurality of sensing elements;

wherein the controller is configured to calculate a multi-dimensional position of the movable object based on the output voltage of the at least one of the plurality of sensing elements, wherein the multi-dimensional position includes a gap between the movable portion and the plurality of sensing elements.

12. The position measurement system of claim 11, wherein the sensing elements comprise Hall effect sensors and the at least one element attached to the movable portion comprises at least one magnet.

13. The position measurement system of claim 11, wherein the plurality of sensing elements comprise transformers wherein each of the transformers includes a primary winding and a secondary winding wrapped around a common core.

14. The position measurement system of claim 13, wherein the controller is configured to calculate a multi-dimensional position of the movable object based on a voltage induced in the secondary winding.

15. The position measurement system of claim 11, wherein the plurality of sensing elements are successively arranged along a first axis and a secondary winding of each of the plurality of sensing elements are connected to voltage busses so that secondary windings of successive sensing elements have alternating polarities.

16. The position measurement system of claim 15, wherein the voltage busses include a first and second voltage bus where secondary windings connected to the first voltage bus produce a first output signal and secondary windings connected to the second voltage bus produce a second signal that is phase shifted from the first signal.

17. The position measurement system of claim 16, wherein the controller is configured to determine a position of the movable object along a first axis and second axis based on the first and second output signals.

18. The position measurement system of claim 11, wherein the plurality of sensing elements are arranged along a first axis and a third axis where secondary windings of the plurality of sensing elements are connected to voltage busses so that secondary windings of successive sensing elements along the first and third axes have alternating polarities.

19. The position measurement system of claim 18, wherein the voltage busses include a first, second, third and fourth voltage bus where secondary windings connected to the first and third voltage busses produce a first and third output signals and secondary windings connected to the second and fourth voltage busses produce a second and fourth output signal where the second output signal is phase shifted from first output signal and the fourth output signal is phase shifted from the third output signal.

20. The position measurement system of claim 19, wherein the controller is configured to determine position of the movable object along a first and second axis based on the first and second output signals and to determine a position of the movable object along a third axis based on the third and fourth output signals.

21. The position measurement system of claim 18, wherein the controller is configured to simultaneously determine a three dimensional position of the movable object wherein the three dimensional position comprises a planar position and an air gap between the movable object and the plurality of sensing elements.

22. A method comprising:

inducing at least one output signal in at least a portion of at least one sensing element in response to at least one movable element moving into proximity with the at least one sensing element; and

calculating a multi-dimensional position of a movable object to which the movable element is attached based on the at least one output signal of the at least one sensing element;

wherein the multi-dimensional position includes a gap between the movable object and the at least one sensing element.

23. The method of claim 22, wherein calculating the multi-dimensional position comprises calculating a planar position of the movable object and an air gap between the movable object and the at least one sensing element.

24. The method of claim 22, wherein inducing at least one output signal comprises inducing an output signal in at least one Hall effect sensor.

25. The method of claim 22, wherein the at least one sensing element comprises a primary winding and a secondary winding wrapped around a common core and inducing at least one output signal comprises inducing a signal in the secondary winding.

26. The method of claim 25, wherein calculating a multi-dimensional position comprises calculating the three dimensional position of the movable object based on a voltage induced in the secondary winding.

27. The method of claim 22, further comprising successively arranging the at least one sensing element along a first axis and a secondary winding of each of the at least one sensing element is connected to voltage busses so that secondary windings of successive sensing elements have alternating polarities.

28. The method of claim 27, wherein the voltage busses include a first and second voltage bus where secondary windings connected to the first voltage bus produce a first output signal and secondary windings connected to the second voltage bus produce a second signal that is phase shifted from the first signal.

29. The method of claim 28, wherein calculating the multi-dimensional position includes determining a position of the movable object along a first axis and second axis based on the first and second output signals.

30. The method of claim 22, further comprising arranging the at least one sensing element along a first axis and a third axis where a secondary winding of the at least one sensing element is connected to voltage busses so that secondary windings of successive sensing elements along the first and third axes have alternating polarities.

31. The method of claim 30, wherein the voltage busses include a first, second, third and fourth voltage bus where secondary windings connected to the first and third voltage busses produce a first and third output signals and secondary windings connected to the second and fourth voltage busses produce a second and fourth output signal where the second output signal is phase shifted from first output signal and the fourth output signal is phase shifted from the third output signal.

32. The method of claim 31, wherein calculating the multi-dimensional position includes determining a position of the movable object along a first and second axis based on the first and second output signals and determining a position of the movable object along a third axis based on the third and fourth output signals.