System Identification of Neonatal Incubator based on Adaptive ARMAX Technique

摘要

The existence of thermal disturbance like opening of incubator clapper was considered as principal cause for possible significant incubator heat loss; therefore understanding this phenomenon is definitely essential for optimal design of a neonatal incubator. This study investigates the effect of instantaneous thermal disturbances on convective heat flux from surrounding environment to inside the incubator. Realtime temperature data was collected inside incubator from five points according to the IEC-60601 standards, using high sensitive RTD sensors with 0.01°C temperature resolution. The thermal dynamic properties of neonatal incubator were evaluated using adaptive system identification. The experiment was conducted using inline adaptive auto regressive moving average with exogenous input (ARMAX) algorithm, which was embedded in computation loop using LabVIEW~R-System identification toolkit. Temperature gradient effect of single measurement point and convective heat transfer of neonatal incubator were determined. System dynamics of accurate and precise sensors response were obtained for spatial temperature distribution inside incubator. Relative humidity of corresponding points was computed using Magnus approximation. Dynamic model of incubator was obtained by varying heat flux to the incubator. Disturbance model was obtained by measuring incubator clappers opening, which is implemented by using potentiometer hinged with clapper. The derived model was tested and approved using linear regression analysis.