Contactless interrogation of sensors for smart structures
First Claim
1. Apparatus for contactless interrogation of a sensor integrally disposed with a structure comprising:
- coil means for coupling signals across a gap between a sensing circuit having a sense coil and an interrogation circuit having an exciter coil connectable to a supply, said sensing circuit operating as a load that changes in relation to the sensor output;
said interrogation circuit comprising means for detecting amplitude of a signal responsive to said load and induced in said exciter coil across said gap; and
control means for determining the sensor output based on said detected amplitude compensated for said gap.
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Accused Products
Abstract
Apparatus for contactless interrogation of an sensor integrally disposed with a structure including a pair of coils for coupling signals across a gap between a sensing circuit having a sense coil and an interrogation circuit having an exciter coil connectable to a variable frequency supply, the sensing circuit comprising a circuit for changing current through the sense coil in relation to the sensor output; the interrogation circuit comprising a circuit for detecting current in the exciter coil induced by the sense coil current; and control means for determining the sensor output based on the exciter coil current compensated for the gap.
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Citations
33 Claims
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1. Apparatus for contactless interrogation of a sensor integrally disposed with a structure comprising:
- coil means for coupling signals across a gap between a sensing circuit having a sense coil and an interrogation circuit having an exciter coil connectable to a supply, said sensing circuit operating as a load that changes in relation to the sensor output;
said interrogation circuit comprising means for detecting amplitude of a signal responsive to said load and induced in said exciter coil across said gap; and
control means for determining the sensor output based on said detected amplitude compensated for said gap. - View Dependent Claims (2, 3, 4, 5, 6, 7, 8, 9, 33)
- coil means for coupling signals across a gap between a sensing circuit having a sense coil and an interrogation circuit having an exciter coil connectable to a supply, said sensing circuit operating as a load that changes in relation to the sensor output;
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10. A method for contactless interrogation of a sensor of the type that exhibits an output characteristic that changes in relation to a physical parameter comprising the steps of:
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a. using the sensor characteristic to determine a variable component in a reactive circuit; b. applying a first frequency input signal to the circuit using magnetic coupling across a gap with said first frequency being in a range such that a first circuit output is independent of the variable component; c. applying a second frequency input signal to the circuit with said second frequency being in a range such that a second circuit output is dependent on the variable component; and d. determining the sensor output as a function of said first and second circuit outputs. - View Dependent Claims (11, 12, 13, 14, 15, 16, 17, 18, 19, 20, 21, 22, 23)
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24. Apparatus for contactless interrogation of a sensor of the type that exhibits a characteristic that changes in known relation to a physical parameter, the apparatus comprising reactive circuit means including a component having a value that is a function of the sensor characteristic;
- coupler means for applying first and second input signals to said circuit means at two different frequencies across a gap and for detecting first and second output signals produced by said circuit means; and
control means for controlling said input signals and interpreting said output signals;
said first output signal being related to said gap independent of said component value, and said second output signal being related to said component value. - View Dependent Claims (25, 26, 27, 28, 29, 30, 31, 32)
- coupler means for applying first and second input signals to said circuit means at two different frequencies across a gap and for detecting first and second output signals produced by said circuit means; and
Specification