Sensors and methods for sensing displacement using radar

• US 5,760,731 A
• Filed: 12/19/1995
• Issued: 06/02/1998
• Est. Priority Date: 12/19/1995
• Status: Expired due to Fees

• Current Assignee: Fisher Controls International LLC (Emerson Electric Company)
• Original Assignee: Fisher Controls International LLC (Emerson Electric Company)
• Inventors: Holmes, David W.
• Primary Examiner(s): Pihulic, Daniel T.
• Application Number:
  US08/574,617
• Time in Patent Office: 896 Days
• Field of Search: 342/61, 342/118, 342/193, 342/28, 342/21, 73/660, 310/328
• US Class Current: 342/118
• CPC Class Codes: G01S 13/56 for presence detection presence detection using near field arrangements G01V3/00, e.g. G01V3/08, G01V3/12; burglar, theft or intruder alarms with electrical actuation G08B13/22 - G08B13/26
• CPC Class Codes: G01S 13/88 Radar or analogous systems specially adapted for specific applications electromagnetic prospecting or detecting of objects, e.g. near-field detection, G01V3/00
• CPC Class Codes: G01S 7/032 Constructional details for solid-state radar subsystems

Abstract

A sensor for sensing a displacement in a mechanical system using radar utilizes a miniaturized radar transceiver formed, typically, on a silicon chip. The transceiver is mounted to a fixed surface that senses a displacement of a moving surface. The moving surface is typically located in mechanical communication with a system to be sensed. By using appropriate translating circuitry, an accurate determination of the nature of displacement of the mechanical system can be made. Mechanical systems sensed can include rotating and sliding components such as motors, valves and pressure gauges. Sensors according to this invention are highly accurate and reliable.

Claims

1. A sensor comprising:

a miniaturized radar transceiver microchip mounted on a first surface;

a second surface that is interconnected with a mechanical system having displacement to be sensed, the second surface being constructed and arranged to move relative to the first surface, the second surface being located relative to the miniaturized radar transceiver microchip so that radar waves from the miniaturized radar transceiver microchip are passed between the first surface and the second surface, and the miniaturized radar transceiver microchip generates a sensor signal representative of an amount of movement of the second surface relative to the first surface; and

a translating circuit, responsive to the sensor signal, that determines a location of the second surface relative to the first surface so that an operation performed by the second surface can be sensed.

2. The sensor as set forth in claim 1 wherein the second surface comprises a rotating shaft having an irregular surface that passes through the radar waves of the miniaturized radar transceiver microchip as the shaft rotates.

3. The sensor as set forth in claim 2 wherein the irregular surface comprises a repeating undulating surface disposed about at least a part of a perimeter of the shaft.

4. The sensor as set forth in claim 2 wherein the irregular surface comprises an edge that one of increases and decreases substantially continuously about a given portion of the circumference of the shaft.

5. The sensor as set forth in claim 4 wherein the edge defines a cam-shape.

6. The sensor as set forth in claim 2 wherein the irregular surface comprises a gear having a plurality of teeth.

7. The sensor as set forth in claim 1 wherein the second surface comprises a shaft having an axis of elongation and has an irregular surface thereon that passes through the radar waves of the miniaturized radar transceiver microchip as the shaft moves relative to the axis of elongation.

8. The sensor as set forth in claim 7 wherein the irregular surface comprises a surface that varies in distance from the axis of elongation at different points therealong taken along a direction of the axis of elongation.

9. The sensor as set forth in claim 8 wherein the irregular surface comprises a ramped surface.

10. The sensor as set forth in claim 7 wherein the shaft comprises an actuator for a control valve.

11. The sensor as set forth in claim 10 wherein the translating circuit includes a circuit for determining a state of a gate in the valve.

14. The sensor as set forth in claim 1 wherein the shaft comprises a continuously rotating shaft interconnected with a source of motive power and wherein the translating circuit includes circuitry for determining at least one of a rotational speed and rotational acceleration of the shaft.

15. The sensor as set forth in claim 1 wherein the second moving surface comprises a diaphragm constructed and arranged to move toward and away from the first surface in response to a force supplied to the diaphragm.

16. The sensor as set forth in claim 15 wherein the force comprises a fluid pressure.

17. The sensor as set forth in claim 15 wherein the diaphragm includes a mass responsive to an applied acceleration thereto constructed and arranged so that the diaphragm moves in response to a predetermined acceleration applied thereto.

18. The sensor as set forth in claim 1 wherein the second surface comprises an enclosure that moves relative to the first surface in response to a predetermined pressure applied thereto.

19. The sensor as set forth in claim 18 wherein the enclosure comprises a tube located adjacent the miniaturized radar transceiver microchip.

20. The sensor as set forth in claim 19 wherein the tube comprises a tube that defines a bent shape at low pressures, the tube being constructed and arranged to move into a more-straightened orientation in response to increased pressures applied thereinto.

21. The sensor as set forth in claim 1 wherein the second surface is mounted so that at least a portion of it moves toward and away from the miniaturized radar transceiver microchip at predetermined times and wherein the translation circuit includes a circuit for determining when a predetermined level of vibration has occurred within the second surface.

22. The sensor as set forth in claim 21 wherein the second surface comprises a rotating shaft and wherein the translating circuit includes a circuit for determining when a predetermined maximum amount of wobble in the shaft has occurred.

12. The sensor as set forth in claim I wherein the second moving surface comprises a rotating shaft interconnected with a valve gate, the valve gate being actuated by rotation of the shaft.

13. The sensor as set forth in claim 12 wherein the translating circuit includes a circuit for determining a state of a gate in the valve.

23. An axial translation sensor comprising:

a fixed surface having a miniaturized radar transceiver microchip mounted thereon;

a moving surface that moves along an axial direction relative to the fixed surface and including an irregular surface shape along at least a portion thereof in communication with the miniaturized radar transceiver microchip, so that radar waves from the miniaturized radar transceiver microchip are passed between the fixed surface and the moving surface, and the miniaturized radar transceiver microchip generates a sensor signal representative of an amount of axial translation of the moving surface relative to the fixed surface; and

circuitry, responsive to the sensor signal, for determining axial translation based upon movement of the irregular surface shape relative to the miniaturized radar transceiver microchip.

24. The axial translation sensor as set forth in claim 23 wherein the moving surface comprises a linear actuator.

25. The axial translation sensor as set forth in claim 24 wherein the linear actuator is interconnected with a valve.

26. A rotational sensor comprising:

a rotationally fixed surface having a miniaturized radar transceiver microchip mounted thereon;

a rotationally moving surface having an irregular surface shape thereon positioned relative to the radar transceiver microchip and having a surface that varies about at least a portion of a perimeter of the rotating surface, so that radar waves from the miniaturized radar transceiver microchip are passed between the fixed surface and the moving surface, and the miniaturized radar transceiver microchip generates a sensor signal representative of an amount of rotational displacement of the moving surface relative to the fixed surface; and

a translating circuit, responsive to the sensor signal, for determining a rotational displacement of the moving surface relative to the fixed surface.

27. The rotational sensor as set forth in claim 26 wherein the rotating surface comprises a rotating actuator shaft.

28. The rotational sensor as set forth in claim 27 wherein the rotating actuator shaft is interconnected with a rotationally actuated valve.

29. The rotational sensor as set forth in claim 26 wherein the surface shape comprises a cam shape.

30. A pressure sensor comprising:

a miniaturized radar transceiver microchip mounted to transmit radar waves between a fixed surface and a moving surface, the moving surface being in communication with a fluid so that variation in a pressure of the fluid causes movement of the moving surface relative to the fixed surface, so that radar waves from the miniaturized radar transceiver microchip are passed between the fixed surface and the moving surface, and the miniaturized radar transceiver microchip generates a sensor signal representative of an amount of movement of the moving surface relative to the fixed surface; and

a translating circuit, responsive to the sensor signal, that determines the pressure of the fluid based upon a relative movement of the moving surface relative to the fixed surface.

31. The pressure sensor as set forth in claim 30 wherein the moving surface comprises a diaphragm having a relatively thin wall.

32. The pressure sensor as set forth in claim 31 wherein the wall includes a plurality of undulations constructed and arranged to increase displacement of the diaphragm in response to a fluid pressure applied thereto.

33. The pressure sensor as set forth in claim 30 wherein the moving surface comprises a sealed tube having a first shape and a second shape, constructed and arranged to move between the first shape and the second shape in response to increased fluid pressure applied thereinto.

34. A vibration sensor comprising:

a fixed surface having a miniaturized radar transceiver microchip mounted thereto;

a moving surface having a predetermined mass constructed and arranged to move in response to a predetermined amplitude and frequency of vibration applied thereto, so that radar waves from the miniaturized radar transceiver microchip are passed between the fixed surface and the moving surface, and the miniaturized radar transceiver microchip generates a sensor signal representative of an amount of movement of the moving surface relative to the fixed surface; and

a translating circuit, responsive to the sensor signal, for determining a level of vibration in the moving surface.

35. The vibration sensor as set forth in claim 34 wherein the moving surface comprises a relatively-thin-walled plate having a mass mounted upon at least a portion thereof.

36. A method for sensing movement of a mechanical system comprising:

providing a fixed surface and locating a miniaturized radar transceiver microchip relative to the fixed surface;

said miniaturized radar transceiver microchip transmitting a radar beam between the fixed surface and a moving surface that is interconnected with the mechanical system;

said miniaturized radar transceiver microchip receiving a reflected radar beam indicative of an amount of movement of the moving surface; and

determining a degree of movement in the mechanical system in response to the reflected radar beam.

37. The method as set forth in claim 36 further comprising moving the moving surface in response to an applied pressure from a fluid.

38. The method as set forth in claim 36 further comprising moving the moving surface in response to an mechanical vibration.

39. The method as set forth in claim 38 wherein the step of moving includes rotating a shaft and wherein the step of determining includes determining a wobble in the rotating shaft.

40. The method as set forth in claim 36 further comprising moving the moving surface about an axis of rotation and passing an irregular surface on the moving surface through a transmitted beam of the miniaturized radar transceiver microchip.

41. The method as set forth in claim 36 further comprising moving the moving surface linearly and passing an irregular surface through a transmitted beam of the miniaturized radar transceiver microchip.

42. The method as set forth in claim 36 wherein the step of determining includes determining a relative position of the moving surface and thereby determining a state of operation of the mechanical system interconnected with the moving surface.

43. A method for sensing actuation of a valve comprising:

providing a valve casing;

locating a miniaturized radar transceiver microchip relative to a fixed portion of the valve casing;

directing a transmitted beam from the miniaturized radar transceiver microchip between a moving component on the valve casing and the fixed portion; and

determining a position of the moving component based upon a reflected beam received by the miniaturized radar transceiver microchip.