METHOD AND APPARATUS FOR VIBRATION SENSING AND ANALYSIS

• US 20050011266A1
• Filed: 07/16/2003
• Published: 01/20/2005
• Est. Priority Date: 07/16/2003
• Status: Active Grant

• Current Assignee: Computational Systems Incorporated (Emerson Electric Company)
• Original Assignee: PCB Piezotronics, Inc. (Amphenol Corporation)
• Inventors: Robinson, James C., Fulciniti, Nicolas, Illig, Mitchell J., Ashton, William J.
• Granted Patent: US 6,889,553 B2
• Time in Patent Office: Days
• US Class Current: 73/649
• CPC Class Codes: G01H 1/14 Frequency
• CPC Class Codes: G01H 1/16 Amplitude

Abstract

A method and apparatus for sensing and measuring stress waves. The method comprises the steps of: a.) sensing motion, where the motion comprises a stress wave component and a vibration component; b.) separating the stress wave component from the vibration component with a high pass filter to create a signal proportional to the stress wave; c.) amplifying the signal to create an amplified signal; d.) processing the amplified signal with a sample and hold peak detector over a predetermined interval of time to determine peaks of the amplified signal over said predetermined period of time; e.) creating an output signal proportional to the determined peaks of the amplified signal; and, f.) repeating steps d.) and e.). The invention also includes an apparatus for implementing the method of the invention.

Claims

1. A method for sensing and measuring stress waves, comprising:

a.) sensing motion, where said motion comprises a stress wave component and a vibration component;

b.) separating said stress wave component from said vibration component with a high pass filter to create a signal proportional to said stress wave;

c.) amplifying said signal to create an amplified signal;

d.) processing said amplified signal with a sample and hold peak detector over a predetermined interval of time to determine peaks of said amplified signal over said predetermined period of time;

e.) creating an output signal proportional to said determined peaks of said amplified signal; and

,

f.) repeating steps d.) and e.).

2. The method recited in claim 1, further comprising the step of averaging said peaks of said amplified signal.

3. The method recited in claim 1 wherein said high pass filter is selectable about a plurality of frequencies.

4. The method recited in claim 2 wherein said high pass filter is selectable about 1 KHz and 5 KHz.

5. The method of claim 1 wherein said amplifying is done with a logarithmic amplifier.

6. The method of claim 1 wherein said sensing is done with an accelerometer.

7. The method of claim 1 wherein said sensing is done with a strain gauge.

8. An apparatus for sensing and measuring stress waves, comprising:

a.) means for sensing motion, where said motion comprises a stress wave component and a vibration component;

b.) means for separating said stress wave component from said vibration component to create a signal proportional to said stress wave;

c.) means for amplifying said signal to create an amplified signal;

d.) means for processing said amplified signal with a sample and hold peak detector over a predetermined interval of time to determine peaks of said amplified signal over said predetermined period of time;

e.) means for creating an output signal proportional to said determined peaks of said amplified signal; and

,

f.) means for repeating steps d.) and e.).

9. The apparatus recited in claim 8 wherein said means for sensing is an accelerometer.

10. The apparatus recited in claim 8 wherein said means for sensing is a strain gauge.

11. The apparatus recited in claim 8 wherein said means for separating said stress wave component from said vibration component to create a signal proportional to said stress wave is a high pass filter.

12. The apparatus recited in claim 11 wherein said means for separating said stress wave from said vibration component to create a signal proportional to said stress wave comprises a selectable dual frequency high-pass filter, selectable to pass signals above at least two different frequencies.

13. The apparatus recited in claim 12 wherein said high-pass filter is selectable about 1 KHz or 5 KHz.