Hardware-in-the-loop setup for contactless skin servo control of neonatal incubators

Abstract

Infant incubators are used to provide an optimal microclimate for premature infants who are thermally instable. Care in the incubator is stressful for the newborn, therefore, current research aims at establishing contact-free monitoring using infrared thermography, thus, improving comfort and reducing skin contact. The skin temperature can already be controlled automatically in current incubators by using adhesive temperature sensors, resulting in possible irritations and damages to the infant’s skin.In this work, a hardware-in-the-loop test bench was developed to test the interaction of all components necessary for skin temperature control with contactless skin temperature measurement. Accordingly, we designed a setup which can control the incubator, the contactless measurement setup, and a thermal neonate phantom. This offers the possibility to test skin temperature controllers immediately in a closed loop and easily simulate physiological and pathological scenarios.After setting up the test bench, the control systems considered were modeled and identified. Subsequently, initial controllers were designed and validated. We recalled that open incubator hand ports have long been considered a significant disturbance for temperature control. Hence, the performance of the current disturbance rejection in the given incubator setting was investigated. Subsequently, a change of the patient’s metabolism was simulated as a specific challenge.In our case, all controllers investigated were able to stabilize the skin temperature compared to the open-loop case. In the future, the presented hardware-in-the-loop concept will help to design and sufficiently validate skin temperature controllers for subsequent clinical trials.