ABSTRACT:

During manned bomb disposal missions, the combination of the protective suit's weight (37 kg), physical activity, high ambient temperatures, and restricted airflow can cause the operative's temperature to rise to dangerous levels during missions, impairing their physical and mental ability. This work proposes to use body sensornetworks (BSNs) to increase the safety of operatives in such missions through detailed physiological monitoring, fusion of health information, and remote alerts. Previous trials conducted by the authors have shown no correlation between the suit wearer's temperature at any single skin site and their core temperature, nor between single-point temperature variations and subjective thermal sensation. This paper reports on the development of a wearable, wireless, networked sensing system suitable for integration within the suit and deployment in manned missions. A sensor fusion and modeling approach is proposed that estimates the overall thermal sensation of the suit wearer, in real time, based on the multipoint temperature data. Zhang's thermal sensation model was used in this work. Modeling is performed locally to enable cooling system actuation, provide local feedback, and accommodate application specific constraints. Experimentation with the prototype confirms the importance of multisite skin measurement, timely cooling actuation, and monitoring the operative's thermal state. Evaluation of Zhang's model highlights the need for a bespoke model to account for suit and missionspecific factors. The deployed BSN has been evaluated through experimental trials using a number of subjects inmission-like conditions and has been shown to be appropriate for the target application.