APPARATUS AND METHOD FOR MEASURING DISPLACEMENT OF A CURVED SURFACE USING DUAL LASER BEAMS

• US 20100085578A1
• Filed: 10/08/2008
• Published: 04/08/2010
• Est. Priority Date: 10/08/2008
• Status: Active Grant

• Current Assignee: Richard M. Weiss Revocable Trust
• Original Assignee: Richard M. Weiss Revocable Trust
• Inventors: Weiss, Richard M., Butler, Joseph H.
• Granted Patent: US 7,864,342 B2
• Time in Patent Office: Days
• US Class Current: 356/614
• CPC Class Codes: G01B 11/026 by measuring distance between sensor and object G01B11/0608 takes precedence
• CPC Class Codes: G01S 17/87 Combinations of systems using electromagnetic waves other than radio waves
• CPC Class Codes: G01S 7/481 Constructional features, e.g. arrangements of optical elements

Abstract

An apparatus measures displacement of a structure having a curved surface, such as a pipe, conduit, shaft or rod. The apparatus includes a support structure having opposing first and second ends, with a first laser distance measurement device at the first end and a second laser distance measurement device at the second end. The laser distance measurement devices generate dual laser beams that illuminate the curved surface of the structure, detect laser energy reflected from the curved surface of the structure, and generate distance signals based on the detected laser energy. A measurement device on the support structure measures a spacing between the two laser beams. The support structure is pivotally attached to a stabilizing base, thereby providing for the tilting of the support structure and the laser beams. An inclinometer on the support structure measures an angle of tilt. A computer processor calculates position values indicating displacement of the curved surface based on the distance signals, the spacing between the laser beams, the radius of curvature of the curved surface, and the angle of tilt of the laser beams. Tripod-mounted and portable handheld versions of the apparatus are described.

Claims

1. An apparatus for measuring displacement of a structure having a curved surface, the apparatus comprising:

a support structure having opposing first and second ends;

a first laser distance measurement device disposed adjacent the first end of the support structure, the first laser distance measurement device for generating a first laser beam that illuminates the curved surface of the structure, for detecting laser energy reflected from the curved surface of the structure, and for generating a first distance signal based on the detected laser energy;

a second laser distance measurement device disposed adjacent the second end of the support structure, the second laser distance measurement device for generating a second laser beam that illuminates the curved surface of the structure, for detecting laser energy reflected from the curved surface of the structure, and for generating a second distance signal based on the detected laser energy; and

a computer processor for calculating position values indicating displacement of the structure based on the first and second distance signals, a spacing between the first and second laser beams, and a radius of curvature of the curved surface.

2. The apparatus of claim 1 further comprising a measurement device disposed on the support structure for measuring the spacing between the first and second laser beams.

3. The apparatus of claim 1 further comprising an inclinometer disposed on the support structure for measuring an angle of tilt of the first and second laser beams.

4. The apparatus of claim 1 further comprising a stabilizing base to which the support structure is pivotally attached, thereby providing for tilting of the support structure and the first and second laser beams with respect to the structure having the curved surface.

5. The apparatus of claim 1 wherein the curved surface comprises a cylindrical surface, and wherein the computer processor calculates the position values according to:

6. The apparatus of claim 1 wherein the support structure and the first and second laser distance measurement devices are disposed within a portable handheld housing.

7. An apparatus for measuring displacement of a structure having a curved surface, the apparatus comprising:

a support structure having opposing first and second ends;

a first laser distance measurement device disposed adjacent the first end of the support structure, the first laser distance measurement device for generating a first laser beam that illuminates the curved surface of the structure, for detecting laser energy reflected from the curved surface of the structure, and for generating a first distance signal based on the detected laser energy;

a second laser distance measurement device disposed adjacent the second end of the support structure, the second laser distance measurement device for generating a second laser beam that illuminates the curved surface of the structure, for detecting laser energy reflected from the curved surface of the structure, and for generating a second distance signal based on the detected laser energy;

a measurement device disposed on the support structure for measuring a spacing between the first and second laser beams;

a stabilizing base to which the support structure is pivotally attached to allow tilting of the support structure and the first and second laser beams with respect to the structure having the curved surface;

an inclinometer disposed on the support structure for measuring an angle of tilt of the first and second laser beams; and

a computer processor for calculating position values indicating displacement of the structure based on the first and second distance signals, a spacing between the first and second laser beams, a radius of curvature of the curved surface, and the angle of tilt of the first and second laser beams.

8. The apparatus of claim 7 wherein the support structure, the first and second laser distance measurement devices, the measurement device for measuring the spacing between the first and second laser beams, and the inclinometer are disposed within a portable handheld housing.

9. A method for measuring displacement of a structure having a curved surface, the method comprising:

(a) generating first and second laser beams that illuminate the curved surface of the structure, the first and second laser beams being substantially parallel to each other;

(b) detecting laser energy reflected from the curved surface of the structure;

(c) generating a first distance signal based on the detected laser energy, where the first distance signal is indicative of a first distance to a first portion of the curved surface;

(d) generating a second distance signal based on the detected laser energy, where the second distance signal is indicative of a second distance to a second portion of the curved surface;

(e) determining a spacing between the first and second laser beams;

(f) calculating data values indicating a characteristic of the movement of the structure based on the first and second distance signals, the spacing between the first and second laser beams, and a radius of curvature of the curved surface; and

(g) displaying the data values on a display device to provide information regarding the movement of the structure.

10. The method of claim 9 further comprising measuring an angle of tilt of the first and second laser beams, wherein step (f) comprises calculating data values indicating a characteristic of the movement of the structure based on the first and second distance signals, the spacing between the first and second laser beams, the radius of curvature of the curved surface, and the angle of tilt of the first and second laser beams.

11. The method of claim 10 wherein the curved surface comprises a cylindrical surface, and the calculating of step (f) is performed according to:

12. The method of claim 9 further comprising the step of performing comparative analysis of the data values over time to correlate the movement of the structure to fatigue and stresses in the structure.

13. An apparatus for measuring displacement of a structure having a curved surface, the apparatus comprising:

means for generating first and second laser beams that illuminate the curved surface of the structure, the first and second laser beams being substantially parallel to each other;

means for detecting laser energy reflected from the curved surface of the structure;

means for generating a first distance signal based on the detected laser energy, where the first distance signal is indicative of a first distance to a first portion of the curved surface;

means for generating a second distance signal based on the detected laser energy, where the second distance signal is indicative of a second distance to a second portion of the curved surface;

means for determining a spacing between the first and second laser beams;

means for calculating data values indicating a characteristic of the movement of the structure based on the first and second distance signals, the spacing between the first and second laser beams, and a radius of curvature of the curved surface; and

means for displaying the data values to provide information regarding the movement of the structure.