Method and system for correcting a temperature measurement signal
View Patent ↗A method including digitally modelling a temperature measured by a sensor by using a modeled signal and estimating a lag error signal for the sensor from the modeled signal and a signal obtained by filtering the modeled signal, the filter having as a parameter an estimate of a time constant of the sensor, and correcting the measurement signal delivered by the sensor by the estimated lag error signal. The time constant of the sensor is estimated as a function of time from the measurement signal and the modeled signal.
1. A method of correcting a temperature measurement signal delivered by a sensor, the method comprising:
digitally modeling the temperature measured by the sensor by using a modeled signal;
estimating a lag error signal for the sensor from the modeled signal and a signal obtained by filtering the modeled signal, the filter having as a parameter an estimate of a time constant of the sensor; and
correcting, using a processor, the measurement signal delivered by the sensor by the estimated lag error signal;
wherein the time constant of the sensor is estimated as a function of time from the measurement signal and the modeled signal
wherein, to estimate the time constant of the sensor, the following operations are performed:
(a) obtaining first and second signals, respectively, by differentiating the measurement signal and the modeled signal;
(b) evaluating a difference between the absolute value of the first signal and the absolute value of the second signal; and
(c) estimating the time constant of the sensor from the evaluated difference.
2. A correction method according to claim 1 , wherein the time constant of the sensor is estimated from the difference using an integral corrector type filter having a predetermined gain as a parameter.
3. A correction method according to claim 1 , wherein, before the estimating the time constant, the absolute value of the first signal is compared to a predetermined threshold.
4. A correction method according to claim 1 , wherein after the estimating the time constant, it is verified that the estimated time constant is between a predefined minimum value and a predefined maximum value.
5. A system for correcting a temperature measurement signal delivered by a sensor, the system comprising:
means for digitally modeling the temperature measured by the sensor by using a modeled signal;
means for estimating a time constant of the sensor;
means for filtering the modeled signal, having as a parameter the estimated time constant of the sensor;
means for estimating a lag error signal for the sensor from the modeled signal and filtered signal from the means for filtering; and
means for correcting the measurement signal delivered by the sensor using the estimated lag error signal;
wherein the means for estimating the time constant of the sensor estimates the time constant as a function of time from the measurement signal and the modeled signal
wherein, the means for estimating the time constant of the sensor, include performing the following operations:
(a) obtaining first and second signals, respectively, by differentiating the measurement signal and the modeled signal;
(b) evaluating a difference between the absolute value of the first signal and the absolute value of the second signal; and
(c) estimating the time constant of the sensor from the evaluated difference.
6. A turbojet engine comprising at least one system for correcting a temperature measurement signal delivered by a sensor according to claim 5 .