Active temperature differential compensation for strain gage based sensors

• US 20090056466A1
• Filed: 08/29/2007
• Published: 03/05/2009
• Est. Priority Date: 08/29/2007
• Status: Active Grant

• Current Assignee: Honeywell International Inc.
• Original Assignee: Honeywell International Inc.
• Inventors: Moran, Michael E., Liu, John, Robinson, Jason R., Gregory, Sean D.
• Granted Patent: US 7,647,837 B2
• Time in Patent Office: Days
• US Class Current: 73/766
• CPC Class Codes: G01G 3/1418 for temperature variations
• CPC Class Codes: G01G 3/18 Temperature-compensating arrangements
• CPC Class Codes: G01L 1/2281 for temperature variations

Abstract

An active temperature differential compensation for strain gage based sensors. An array of temperature sensors can be placed at the gage locations to measure the difference in temperature that induces strain on the strain gages. The output of the temperature sensor network can be placed in series with the strain gage network to directly compensate the induced voltage caused by the temperature gradient and/or employed as the input of a mathematical algorithm that can compensate the output from the strain gage bridge to dynamically correct unwanted thermally induced strain in the strain gages.

Claims

1. A differential temperature compensation method for strain gage based sensors comprising:

providing an array of temperature sensing devices at locations along a strain gage;

measuring the temperature differential between said temperature sensing devices provided at said locations;

utilizing said temperature differential measured at said temperature sensing devices to dynamically correct thermally induced strain in said strain gage.

2. The method of claim 1 wherein said correction is analog.

3. The method of claim 2 wherein said analog method employs the output of said array of temperature sensing devices placed in series with output from said strain gage to directly compensate the induced voltage caused by temperature gradient.

4. The method of claim 1 wherein said correction is digital.

5. The method of claim 4 wherein said digital output from the array of temperature sensing devices is processed together with output from said strain gage to directly compensate for said output from said strain gage.

6. The method of claim 1 wherein said method is a dynamic temperature gradient compensation method as opposed to a static compensation.

7. The method of claim 1 wherein said differential temperature compensation method is used with at least one strain gage based sensor to measure at least one of:

load, pressure, torque and acceleration.

8. The method of claim 3 wherein said differential temperature compensation method is used with at least one strain gage based sensor to measure at least one of:

load, pressure, torque and acceleration.

9. The method of claim 5 wherein said differential temperature compensation method is used with at least one strain gage based sensor to measure at least one of:

load, pressure, torque and acceleration.

10. A strange gauge sensor system adapted with differential temperature compensation, comprising:

at least one strain gauge device deployed at a strain gauge measurement locations; and

an array of temperature sensing devices wherein individual temperature sensing devices comprising said array of temperature sensing devices are each disposed at various locations along said at least one strain gauge;

wherein measurements of temperature differential between said individual temperature sensing devices are utilized to dynamically correct thermally induced strain in said at least one strain gage.

11. The system of claim 10 wherein analog output comprising said measurements from said individual temperature sensing devices is placed in series with output from said at least one strain gage to directly compensate the induced voltage caused by temperature gradient.

12. The system of claim 10 wherein said array of temperature sensing devices are adapted for use with said strain gauges to measure at least one of:

load, pressure, torque and acceleration.

13. The system of claim 11 wherein said array of temperature sensing devices is adapted for use with said at least one strain gauge to measure at least one of:

load, pressure, torque and acceleration.

14. A strain gauge sensing system, comprising:

strain sensing elements electrically connected in the formation of a Wheatstone bridge circuit;

temperature sensing elements electrically connected in the formation of a Wheatstone bridge circuit and individually associated with each of said strain sensing elements in the Wheatstone bridge circuit;

wherein output measured from said temperature sensing elements is used to compensate for temperature effects on output from said strain sensing elements.

15. The system of claim 14 wherein analog output comprising said measurements from said temperature sensing devices is placed in series with output from said strain sensing elements to directly compensate the induced voltage caused by temperature gradients on said strain sensing elements.

16. The system of claim 14 wherein said temperature sensing devices are adapted for use with said strain sensing elements to measure at least one of:

load, pressure, torque and acceleration.

17. The system of claim 15 wherein said temperature sensing devices is adapted for use with stain sensing element of at least one strain gauge to measure at least one of:

load, pressure, torque and acceleration.