Sensor fault detection, isolation and accommodation
First Claim
1. A method of detecting sensor faults in a system, the method comprising the steps of:
- generating a modeled sensor value of each actual sensor value as a function of a plurality of other sensors;
computing an absolute value of a difference between the actual sensor value and the modeled sensor value;
comparing the difference to a predetermined threshold; and
declaring the sensor as faulted if the difference is greater than the predetermined threshold.
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Accused Products
Abstract
A sensor in an engineering system can be tested to detect, isolate and accommodate faults. Initially, a modeled sensor value of each actual sensor value is generated as a function of a plurality of other sensors. An absolute value of a difference between the actual sensor value and the modeled sensor value is then computed and compared to a predetermined threshold. A sensor fault is detected if the difference is greater than the predetermined threshold. Once a sensor fault is detected, it is isolated using hypothesis testing and maximum wins strategies. After the fault is isolated, the fault is accommodated by substituting the modeled sensor value for the actual sensor value.
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Citations
22 Claims
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1. A method of detecting sensor faults in a system, the method comprising the steps of:
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generating a modeled sensor value of each actual sensor value as a function of a plurality of other sensors;
computing an absolute value of a difference between the actual sensor value and the modeled sensor value;
comparing the difference to a predetermined threshold; and
declaring the sensor as faulted if the difference is greater than the predetermined threshold. - View Dependent Claims (2, 3, 4, 5)
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6. A method of detecting and isolating sensor faults in a system, the method comprising the steps of:
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generating a modeled sensor value of each actual sensor value as a function of a plurality of other sensors;
computing an absolute value of a difference between the actual sensor value and the modeled sensor value;
comparing the difference to a predetermined threshold;
declaring the sensor as faulted if the difference is greater than the predetermined threshold; and
applying fault isolation to the potentially faulted sensor. - View Dependent Claims (7, 8, 9, 10, 11, 12, 13)
performing hypothesis testing on the potentially faulted sensor; and
performing maximum wins strategies on the potentially faulted sensor.
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12. A method as claimed in claim 11 wherein the step of performing hypothesis testing comprises the steps of:
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hypothesizing that each sensor is faulted in turn; and
concluding that the hypothesis is correct if replacing the sensor'"'"'s value by its associated modeled sensor value and then repeating fault detection causes subsequent faults detected to decrease.
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13. A method as claimed in claim 11 wherein the step of performing maximum wins strategies comprises the steps of:
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computing a normalized error; and
isolating fault to a sensor with a largest normalized error when the step of performing hypothesis testing indicates more than one sensor as being faulted.
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14. A method of detecting, isolating and accommodating sensor faults in a system, the method comprising the steps of:
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generating a modeled sensor value of each actual sensor value as a function of a plurality of other sensors;
computing an absolute value of a difference between the actual sensor value and the modeled sensor value;
comparing the difference to a predetermined threshold;
isolating the sensor as potentially faulted if the difference is greater than the predetermined threshold; and
accommodating the sensor fault by substituting the actual sensor value of the faulted sensor with its modeled sensor value. - View Dependent Claims (15, 16, 17, 18, 19, 20, 21, 22)
performing hypothesis testing on the potentially faulted sensor; and
performing maximum wins strategies on the potentially faulted sensor.
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20. A method as claimed in claim 19 wherein the step of performing hypothesis testing comprises the steps of:
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hypothesizing that each sensor is faulted in turn; and
concluding that the hypothesis is correct if replacing the sensor'"'"'s value by its associated modeled sensor value and then repeating fault detection causes subsequent faults detected to decrease.
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21. A method as claimed in claim 19 wherein the step of performing maximum wins strategies comprises the steps of:
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computing a normalized error; and
isolating fault to a sensor with a largest normalized error when the step of performing hypothesis testing indicates more than one sensor as being faulted.
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22. A method as claimed in claim 14 wherein modeled sensor value used for sensor accommodation can differ from the modeled sensor value used for detection.
Specification