Method and system for providing sensor redundancy
First Claim
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1. A method of sensing blood glucose values using redundant sensors, comprising:
- obtaining a first glucose reading from a first glucose sensor located at a first site;
obtaining a second glucose reading from a second glucose sensor located at a second site;
deriving a first predictive value for the first glucose sensor corresponding to the first glucose reading using the second glucose reading as an input;
deriving a second predictive value for the second glucose sensor corresponding to the second glucose reading using the first glucose reading as an input;
determining a first error between the first predictive value and the first glucose reading;
determining a second error between the second predictive value and the second glucose reading;
comparing a sum of the absolute error values of the first and second errors to a threshold;
determining a failing sensor exists if the sum of the absolute error values exceed the threshold;
determining whether the first glucose sensor or second glucose sensor has the least error in the sensor signal if the sum of the absolute error values does not exceed the threshold;
calculating a blood glucose value based on the glucose sensor having the least error in the sensor signal; and
reporting the calculated blood glucose value.
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Abstract
A closed loop system or semi-closed loop system for infusing insulin using sensor values applies a redundant sensor system as a fail-safe method against sensor failure. The redundant glucose sensors are used corroborate each other and a failing sensor is detected if the sensors no longer corroborate each other. The use of redundant sensors has the additional benefit of producing better sensor signals compared to the use of a single sensor.
715 Citations
21 Claims
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1. A method of sensing blood glucose values using redundant sensors, comprising:
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obtaining a first glucose reading from a first glucose sensor located at a first site; obtaining a second glucose reading from a second glucose sensor located at a second site; deriving a first predictive value for the first glucose sensor corresponding to the first glucose reading using the second glucose reading as an input; deriving a second predictive value for the second glucose sensor corresponding to the second glucose reading using the first glucose reading as an input; determining a first error between the first predictive value and the first glucose reading; determining a second error between the second predictive value and the second glucose reading; comparing a sum of the absolute error values of the first and second errors to a threshold; determining a failing sensor exists if the sum of the absolute error values exceed the threshold; determining whether the first glucose sensor or second glucose sensor has the least error in the sensor signal if the sum of the absolute error values does not exceed the threshold; calculating a blood glucose value based on the glucose sensor having the least error in the sensor signal; and reporting the calculated blood glucose value. - View Dependent Claims (2, 3, 4, 5, 6, 7, 8, 9, 10)
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11. A closed loop system or semi-closed loop system for infusing insulin using sensor values comprising:
an infusion pump delivering insulin based on a reported blood glucose value derived by a controller configured to perform the steps of;
obtaining a first glucose reading from a first glucose sensor located at a first site;
obtaining a second glucose reading from a second glucose sensor located at a second site;
deriving a first predictive value for the first glucose sensor corresponding to the first glucose reading using the second glucose reading as an input;
deriving a second predictive value for the second glucose sensor corresponding to the second glucose reading using the first glucose reading as an input;
determining a first error between the first predictive value and the first glucose reading;
determining a second error between the second predictive value and the second glucose reading;
comparing a sum of the absolute error values of the first and second errors to a threshold;
determining a failing sensor exists if the sum of the absolute error values exceeds the threshold;
determining whether the first glucose sensor or second glucose sensor has the least error in the sensor signal if the sum of the absolute error values does not exceed the threshold;
calculating a blood glucose value based on the glucose sensor having the least error in the sensor signal; and
reporting the calculated blood glucose value.
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12. A system of sensing blood glucose values using redundant sensors, comprising:
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means for obtaining a first glucose reading from a first glucose sensor located at a first site; means for obtaining a second glucose reading from a second glucose sensor located at a second site; means for deriving a first predictive value for the first glucose sensor corresponding to the first glucose reading using the second glucose reading as an input; means for deriving a second predictive value for the second glucose sensor corresponding to the second glucose reading using the first glucose reading as an input; means for determining a first error between the first predictive value and the first glucose reading; means for determining a second error between the second predictive value and the second glucose reading; means for comparing a sum of the absolute error values of the first and second errors to a threshold; means for determining a failing sensor exists if the sum of the absolute error values exceed the threshold; means for determining whether the first glucose sensor or second glucose sensor has the least error in the sensor signal if the sum of the absolute error values does not exceed the threshold; means for calculating a blood glucose value based on the glucose sensor having the least error in the sensor signal; and means for reporting the calculated blood glucose value. - View Dependent Claims (13, 14, 15, 16, 17, 18, 19, 20, 21)
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Specification