Simplified Closed-loop Thermal Feedback System in Flexible Form Factor for Prosthesis

The development of prosthetics has been benefiting amputees by regaining the functions of their lost body parts such as forearms, limbs, and fingers. Up to now, functional and cosmetic prosthetics that are fully functional and partially movable are widely applied to treat amputees. Those prosthetics are proven with their mechanical functionalities like supporting the body, gripping, pushing, and lifting a specific object. However, still, providing somatosensory sensations including tactile, hardness, and thermal feedback is limited. With the advancement of flexible electronics, a wide variety of sensational feedback systems in wearable and flexible form factors have been developed. Due to their bendable, twistable, and stretchable characteristics, it is highly suitable to be adopted in prosthetics with curved and movable surfaces. Herein, a simplified closed-loop thermal feedback system using a flexible printed circuit embedded with thermistors as thermal sensors and a flexible heater as a heating source that can be merged with prostheses is introduced. Each channel of the heat feedback system is composed of a target thermal sensor and a combination of a thermal sensor and heater for controlling the heater. By monitoring the temperature measured by the sensors, the heat can be reproduced on the epidermis side.