System and method for sensing torque on a rotating shaft

• US 7,458,277 B2
• Filed: 08/27/2007
• Issued: 12/02/2008
• Est. Priority Date: 04/09/2002
• Status: Expired due to Fees

• Current Assignee: Rockwell Automation Technologies Incorporated (Allen-Bradley Co., Inc.)
• Original Assignee: Rockwell Automation Technologies Incorporated (Allen-Bradley Co., Inc.)
• Inventors: Discenzo, Frederick M.
• Primary Examiner(s): NOORI, MAX H
• Application Number:
  US11/845,619
• Publication Number:
  US 20080041141A1
• Time in Patent Office: 463 Days
• Field of Search: 738/00
• US Class Current: 73/800
• CPC Class Codes: G01L 1/241 by photoelastic stress analysis
• CPC Class Codes: G01L 3/12 involving photoelectric means

Abstract

A system and method relating to the measuring of torque in a rotating shaft is provided. An optical torque sensing system comprises a rotating shaft, wherein a sleeve of photo-elastic material overlays a portion of the shaft. A light emitting component delivers light into the photo-elastic material, wherein the light delivered by the light emitting component is directed through the photo-elastic material along an axis of the rotating shaft. A capturing component captures the light that exits the photo-elastic material. The exiting light comprises fringe pattern data, and a computing system computes torsion strain of the shaft based at least in part on the fringe pattern information

Claims

1. A system that monitors a structure associated with a motor, comprising:

a layer of photo-elastic material that substantially surrounds the structure;

a light source that emits a beam of light into the layer, wherein the light ray travels across the layer, in a direction substantially parallel to the surface of the structure;

a notch that is coated with a reflective substance, wherein the edges of the notch are at an angle to the light delivered by the light source such that light is redirected by the notch in a direction substantially parallel to the surface of the structure through the layer;

a light detector that captures a light ray exiting the layer, the exiting ray having at least one of mechanical degradation and alignment characteristics relating to the structure;

an analyzer component that analyzes the received ray of light to determine the characteristics of the structure; and

a control component that can implement correction procedures to the structure.

2. The system of claim 1, wherein the structure is at least one of a shaft, a coupler or a composite joint associated with the motor.

3. The system of claim 1, wherein the photo-elastic material forms a sleeve proximate to the structure.

4. The system of claim 1, wherein the received light ray contains a fringe pattern indicative of torque and strain characteristics.

5. The system of claim 1, wherein the light detector utilizes polarizing filters to capture a fringe pattern exiting the layer.

6. The system of claim 5, wherein the fringe pattern is analyzed to determine mechanical wear or alignment factors of the structure.

7. The system of claim 1, further comprising an artificial intelligence component to facilitate diagnosing current state of characteristics of the structure.

8. The system of claim 7, wherein the characteristics comprise at least one of torque, strain, misalignment or joint integrity.

9. The system of claim 1, wherein the control component performs a corrective measure without human interaction.

10. The system of claim 1, wherein multiple beams of light are transmitted into the layer, in a delayed manner.

11. The system of claim 10, wherein the multiple beams can be utilized to determine characteristics of one region or an entire section of a rotating shaft over time.