Transient study of a feedback measurement system based on thermoresistive sensors
Thermoresistive sensor, Electric equivalence principle, Feedback
systems, Internal model control, Disturbance observer-based control.
This work proposes two techniques aimed at improving feedback systems based on a sensor thermoresistive kept at constant temperature. In order to obtain
better results regarding the effects of the temperature transients of the device in
the measurement, control strategies by internal model with two degrees of freedom and control based on disturbance observer are presented. A temperature derivative compensation method called backward approximation is also proposed in order to minimize the effects of transients in the response of the measurement system based on NTC sensors and provide a faster process of estimating physical quantities. A study on the errors inherent to the discussed approaches is also presented. Simulations of measurements of ambient temperature, fluid velocity and thermal radiation absorbed by the sensor are carried out in the face of changes in temperature reference and disturbances at the sensor input, as well as bench tests of ambient temperature measurements.