Methods and apparatus for vibration detection

• US 7,592,801 B2
• Filed: 03/21/2008
• Issued: 09/22/2009
• Est. Priority Date: 04/08/2004
• Status: Active Grant

• Current Assignee: Allegro Microsystems Incorporated (Sanken Electric Company Limited)
• Original Assignee: Allegro Microsystems Incorporated (Sanken Electric Company Limited)
• Inventors: Doogue, Michael C., Towne, Jay M., Bailey, James M.
• Primary Examiner(s): Aurora; Reena
• Application Number:
  US12/053,004
• Publication Number:
  US 20080164871A1
• Time in Patent Office: 550 Days
• Field of Search: 324/207.13, 324/207.18, 3242072-20722, 32420724-20725, 324/251, 324/207.12, 324/207.26, 338/32.R, 338/32.H, 735/143.1, 735/143.9
• US Class Current: 324/207.25
• CPC Class Codes: G01D 2205/85 Determining the direction of movement of an encoder, e.g. of an incremental encoder
• CPC Class Codes: G01D 5/2451 Incremental encoders G01D5/2454 takes precedence
• CPC Class Codes: G01H 1/003 of rotating machines G01H1/10 takes precedence
• CPC Class Codes: G01R 33/025 Compensating stray fields G01R33/0017 takes precedence

Abstract

Apparatus for detecting vibration of an object adapted to rotate includes one or more vibration processors selected from: a direction-change processor adapted to detect changes in a direction of rotation of the object, a direction-agreement processor adapted to identify a direction of rotation of the object in at least two channels and identify an agreement or disagreement in direction of rotation identified by the at least two channels, a phase-overlap processor adapted to identify overlapping signal regions in signals associated with the rotation of the object, and a running mode processor adapted to identify an unresponsive output signal from at least one of the at least two channels. A method for detecting the vibration of the object includes generating at least one of a direction-change output signal with the direction-change processor, a direction-agreement output signal with the direction-agreement processor, a phase-overlap output signal with the phase-overlap processor, and a running-mode-vibration output signal with the running-mode processor, each indicative of the vibration the object.

Claims

1. Apparatus for detecting a vibration of an object adapted for rotation, comprising:

a plurality of magnetic field sensors for generating an RDIFF signal proportional to a magnetic field at a first location relative to the object and an LDIFF signal proportional to a magnetic field at a second location relative to the object;

at least two rotation detectors, wherein a first one of the rotation detectors is coupled to at least one of the magnetic field sensors and is responsive to the RDIFF signal for providing a first output signal indicative of rotation of the object, and wherein a second one of the rotation detectors is coupled to at least one of the magnetic field sensors and is responsive to the LDIFF signal for providing a second output signal indicative of rotation of the object; and

a vibration processor responsive to the first and second output signals from the at least two rotation detectors for detecting the vibration of the object, the vibration processor comprising one or more vibration detectors including a direction-agreement processor, wherein the direction-agreement processor is configured to generate a first signal indicative of a direction of rotation of the object, to generate a second signal indicative of the direction of rotation of the object, to determine whether the first signal indicative of the direction of rotation has an agreement with or a disagreement with the second signal indicative of the direction of rotation, and to generate a direction-agreement output signal in response to the agreement or disagreement.

2. The apparatus of claim 1, wherein the apparatus comprises two rotation detectors, each of a type selected from a peak-referenced detector or a threshold detector.

3. The apparatus of claim 1, wherein the apparatus comprises four rotation detectors, each of a type selected from a peak-referenced detector or a threshold detector.

4. The apparatus of claim 1, wherein the one or more vibrations detectors includes another different type of vibration detector, the vibration processor further comprising a combining processor coupled to the one or more vibration detectors to combine output signals of the one or more vibration detectors to generate a vibration-decision output signal indicative of the vibration of the object.

5. The apparatus of claim 1, wherein the apparatus is configured for use in an automobile.

6. The apparatus of claim 1, wherein the at least two rotation detectors comprises four rotation detectors providing output signals coupled to the direction-agreement processor, wherein two of the four rotation detectors are threshold detectors and two of the four rotation detectors are peak-referenced detectors, and wherein the vibration of the object is detected in response to a comparison of the direction of rotation of the object as indicated by the output signals of the two threshold detectors with the direction of rotation of the object as indicated by the output signals of the two peak-referenced detectors.

7. The apparatus of claim 1, further comprising an output protocol processor coupled to the vibration processor, the output protocol processor for providing an output signal indicative of the vibration of the object and also indicative of the rotation of the object.

8. The apparatus of claim 7, wherein the output signal provided by the output protocol processor is indicative of the rotation of the object when no vibration is detected by the vibration processor, and wherein the output signal provided by the output protocol processor achieves a substantially static signal value when the vibration is detected by the by the vibration processor.

9. Apparatus for detecting a vibration of an object adapted for rotation, comprising:

a plurality of magnetic field sensors for generating an RDIFF signal proportional to a magnetic field at a first location relative to the object and an LDIFF signal proportional to a magnetic field at a second location relative to the object;

at least two rotation detectors, wherein a first one of the rotation detectors is coupled to at least one of the magnetic field sensors and is responsive to the RDIFF signal for providing a first output signal indicative of rotation of the object, and wherein a second one of the rotation detectors is coupled to at least one of the magnetic field sensors and is responsive to the LDIFF signal for providing a second output signal indicative of rotation of the object; and

a vibration processor responsive to the first and second output signals from the at least two rotation detectors for detecting the vibration of the object, wherein the vibration processor comprises two or more vibration detectors having respective output signals indicative of the vibration; and

a combining processor for combining the output signals of the two or more vibration detectors to provide a vibration-decision output signal indicative of the vibration of the object.

10. The apparatus of claim 9, wherein the two or more rotation detectors comprises two rotation detectors, each of a type selected from a peak-referenced detector or a threshold detector.

11. The apparatus of claim 9, wherein the two or more rotation detectors comprises four rotation detectors, each of a type selected from a peak-referenced detector or a threshold detector.

12. The apparatus of claim 9, wherein the apparatus is configured for use in an automobile.

13. A method for detecting a vibration of an object, comprising:

generating a first signal indicative of a direction of rotation of the object;

generating a second signal indicative of the direction of rotation of the object;

determining whether the first signal indicative of the direction of rotation agrees or disagrees with the second signal indicative of the direction of rotation; and

generating a direction-agreement output signal in response to the determining, wherein the direction-agreement output signal is indicative of the vibration of the object when the determining results in a disagreement.

14. The method of claim 13, wherein the generating the direction-agreement output signal comprises:

determining whether the first signal indicative of the direction of rotation is the same as the second signal indicative of the direction of rotation; and

generating the direction-agreement output signal in response to the determining.

15. The method of claim 14, further comprising combining the direction-agreement output signal with another signal representative of the vibration to provide a vibration-decision output signal indicative of the vibration of the object.

16. The method of claim 13, further comprising providing an output signal indicative of the vibration of the object and also indicative of the rotation of the object.

17. The method of claim 16, wherein the provided output signal is indicative of the rotation of the object when no vibration is detected by the vibration processor, and wherein the provided output signal achieves a substantially static signal value when the vibration is detected by the vibration processor.

18. A method of detecting a vibration of an object, comprising:

providing a first output signal indicative of a rotation of the object with a first rotation detector;

providing a second output signal indicative of a rotation of the object with a second rotation detector;

providing a third output signal indicative of a rotation of the object with a third rotation detector;

providing a fourth output signal indicative of a rotation of the object with a fourth rotation detector;

detecting a first direction of rotation of the object with the first rotation detector and with the second rotation detector;

detecting a second direction of rotation of the object with the third rotation detector and with the fourth rotation detector;

determining whether the first direction of rotation is the same as or different from the second direction of rotation; and

generating a direction-agreement output signal in response to the determining, wherein the direction-agreement output signal is indicative of the vibration of the object when the first direction of rotation is different from the second direction of rotation.

19. The method of claim 18, wherein the first rotation detector is a threshold detector, the second rotation detector is a threshold detector, the third rotation detector is a peak-referenced detector, and the fourth rotation detector is a peak-referenced detector.

20. The method of claim 18, further comprising combining the direction-agreement output signal with another signal representative of the vibration to provide a vibration-decision output signal indicative of the vibration of the object.

21. The method of claim 18, further comprising providing an output signal indicative of the vibration of the object and also indicative of the rotation of the object.

22. The method of claim 21, wherein the provided output signal is indicative of the rotation of the object when no vibration is detected by the vibration processor, and wherein the provided output signal achieves a substantially static signal value when the vibration is detected by the vibration processor.