Toward textile-based heating devices for the distal extremities: Experimental characterization of system design parameters

Supplemental heating systems for the distal extremities often require a tradeoff between wearability and thermal comfort. Textile-based thermal actuation helps manage this tradeoff by increasing comfort of on-body systems. However, textile-based thermal actuation also presents important limitations in the form of current requirements, control structures, and thermal flux afforded. Further, on-body active thermal control is affected by three intersecting thermal systems: the environment, the human body, and the active heating system. Here, we present lessons learned from iterative development of textile-based wearable systems (V1, V2) designed to heat the distal extremities. Experimental characterization of textile actuator power/temperature relationships and limits; actuator performance in cool ambient temperatures and in on-body conditions; and efficacy of closed-loop duty cycle control of actuated skin temperature are presented, and implications of these characteristics for garment system design are discussed.