| US 7,523,671 B2 | ||
| Apparatus, system and method for measuring stress | ||
| Larry M. Oberdier, Royal Oak, Mich. (US); Bruno Lequesne, Troy, Mich. (US); Elias Taye, Macomb Township, Mich. (US); and Thaddeus Schroeder, Rochester Hills, Mich. (US) | ||
| Assigned to Delphi Technologies, Inc., Troy, Mich. (US) | ||
| Filed on Mar. 05, 2007, as Appl. No. 11/713,961. | ||
| Prior Publication US 2008/0216582 A1, Sep. 11, 2008 | ||
| Int. Cl. G01L 1/00 (2006.01); G01L 1/12 (2006.01) | ||
| U.S. Cl. 73—779 [73/862.626] | 18 Claims |
| 18. A system for measuring stress comprising:
a coilless sensor including at least one band of electrically conductive and magnetostrictive material, said band having a
first end and a second end defining a gap therebetween;
a measuring circuit electrically connected to said first and said second ends of said coilless sensor, said measuring circuit
being configured to pass a current through said coilless sensor and measure at least one of an inductance, a resistance and
an impedance of said coilless sensor in response to said current;
a processor in electrical communication with said measuring circuit, said processor being configured to calculate an amount
of stress being applied to said coilless sensor based upon said measured inductance, resistance and impedance; and
wherein said measuring circuit is connected to said coilless sensor with at least four leads, two of said leads being connecting
to said first end of said coilless sensor and another two of said leads being connecting to said second end of said coilless
sensor, wherein one of said leads connected to said first end is configured to pass an oscillating signal to said coilless
sensor, and wherein one of said leads connected to said second end is configured to connect said coilless sensor to ground,
and wherein the other of said connected leads are connected differentially to generate a voltage signal in response to said
measured inductance, resistance and impedance.
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