Inverse corner cube for non-intrusive three axis vibration measurement

• US 6,655,215 B2
• Filed: 06/15/2001
• Issued: 12/02/2003
• Est. Priority Date: 06/15/2001
• Status: Expired due to Fees

• Current Assignee: Honeywell International Inc.
• Original Assignee: Honeywell International Inc.
• Inventors: Hadden, George D.
• Primary Examiner(s): Williams, Hezron
• Assistant Examiner(s): SAINT SURIN, JACQUES M
• Application Number:
  US09/882,341
• Publication Number:
  US 20020189361A1
• Time in Patent Office: 900 Days
• Field of Search: 736/57, 73/18.2, 735/96, 736/53, 736/55, 735/05, 735/041.4, 735/041.2, 73/644.3, 73/85, 356/152.3, 356/740, 356/459, 310/316, 310/321
• US Class Current: 73/657
• CPC Class Codes: G01H 9/00 Measuring mechanical vibrations or ultrasonic, sonic or infrasonic waves by using radiation-sensitive means, e.g. optical means

Abstract

A non-intrusive apparatus and method for measuring vibration of an object along three axes. A vibration measurement device is provided which has three orthogonal right triangular panels forming a pyramidal shape having three 90° angled corners which meet at an apex, wherein each triangular panel has an outer mirrored surface. The device is attached to an object which is subjected to vibration, such that the apex of the device points in a direction away from the object. A beam of light is directed onto the apex of the device such that a portion of the light is reflected off of each mirrored surface, sending reflected light in three directions to three different light sensors. The magnitude of vibration of the object can then be determined in each of three orthogonal directions, along three axes, by measuring the difference in movements of position between the reflected light and a reference beam.

Claims

1. A vibration measurement apparatus which comprises:

a) a vibration measurement device which comprises three triangular panels which are congruent to each other and have the shape of an isosceles right triangle having a 90°

angled corner between two equal length edges, each panel being attached along one of its equal length edges to an equal length edge of one of the other panels and being attached along another of its equal length edges to an equal length edge of another panel, forming an orthogonal pyramidal configuration such that the three 90°

angle corners meet at an apex, and wherein each triangular panel of the pyramidal configuration has an outer mirrored surface;

b) three laser light sensors, each positioned for receiving and detecting changes of position of reflected laser light from one of the triangular panels;

c) a laser capable of projecting a beam of laser light onto a beam splitter;

d) a beam splitter capable of receiving a beam of laser light from the laser;

splitting the beam of laser light into an incident beam segment and three reference beam segments;

directing one of each of the reference beam segments onto one of each of the laser light sensors;

directing the incident beam segment onto the apex of the vibration measurement device and reflecting a portion of the incident beam segment from the mirrored surface of each of the three triangular panels onto one of each of the laser light sensors; and

e) a light measurement implement attached to each of the light sensors, which light measurement implement is capable of measuring movements of position of the reflected portions of the incident beam segments on each of the laser light sensors and comparing said movements of position with the reference beam segment directed to the corresponding sensor.

2. The apparatus of claim 1 wherein each of the triangular panels has the shape of an isosceles right triangle.

3. The apparatus of claim 1 wherein the outer mirrored surfaces of the triangular panels comprise a metal.

4. The apparatus of claim 1 wherein the vibration measurement device has an open base.

5. The apparatus of claim 1 wherein the vibration measurement device has a closed base.

6. The apparatus of claim 1 wherein the light measurement implement is attached to each of the light sensors via fiber optic cables.

7. The apparatus of claim 1 wherein the beam splitter comprises a half silvered mirror.

8. A method for measuring vibrations of an object which comprises:

i) providing a vibration measurement apparatus which comprises;

a) a vibration measurement device which comprises three triangular panels which are congruent to each other and have the shape of an isosceles right triangle having a 90°

angled corner between two equal length edges, each panel being attached along one of its equal length edges to an equal length edge of one of the other panels and being attached along another of its equal length edges to an equal length edge of another panel, forming an orthogonal pyramidal configuration such that the three 90°

angle corners meet at an apex, and wherein each triangular panel of the pyramidal configuration has an outer mirrored surface;

b) three laser light sensors, each positioned for receiving and detecting changes of position of reflected laser light from one of the triangular panels;

c) a laser capable of projecting a beam of laser light onto a beam splitter;

d) a beam splitter capable of receiving a beam of laser light from the laser;

splitting the beam of laser light into an incident beam segment and three reference beam segments;

directing one of each of the reference beam segments onto one of each of the laser light sensors;

directing the incident beam segment onto the apex of the vibration measurement device and reflecting a portion of the incident beam segment from the mirrored surface of each of the three triangular panels onto one of each of the laser light sensors; and

e) a light measurement implement attached to each of the light sensors, which light measurement implement is capable of measuring movements of position of the reflected portions of the incident beam segment on each of the laser light sensors and comparing said movements of position with the reference beam segment directed to the corresponding sensor;

ii) attaching the vibration measurement device to an object which is subjected to vibration, such that the apex of the device points in a direction away from the object and in a direction towards the beam splitter;

iii) projecting a beam of laser light from the laser onto the beam splitter such that the beam splitter splits the beam of laser light into an incident beam segment and three reference beam segments, directs one of each of the reference beam segments onto one of each of the laser light sensors, and directs the incident beam segment onto the apex of the vibration measurement device such that a portion of the incident beam segment is reflected from the mirrored surface of each of the three triangular panels onto one of each of the laser light sensors;

iv) receiving the reflected portions of the incident beam segment with each of the laser light sensors, measuring movements of position of the reflected portions of the incident beam segment on each of the laser light sensors, and comparing said movements of position with the reference beam segment directed to the corresponding sensor; and

v) determining the magnitude of vibration of the object in each of three orthogonal directions by measuring the difference in movements of position between the reference beam segments and the reflected portions of the incident beam segment.

9. The method of claim 8 wherein each of the triangular panels has the shape of an isosceles right triangle.

10. The method of claim 8 wherein the light measurement implement is attached to each of the light sensors via fiber optic cables.

11. The method of claim 8 wherein the vibration measurement device is glued to the object which is subjected to vibration.

12. The method of claim 8 wherein the vibration measurement device is clamped to the object which is subjected to vibration.

13. The method of claim 8 wherein the outer mirrored surfaces of the triangular panels comprise a metal.

14. The method of claim 8 wherein the beam splitter comprises a half silvered mirror.

15. The method of claim 8 wherein the light sensors comprise position sensitive photodiodes.