Multifunctional Composite Spring Capable of Self-Energy Harvesting Based on Triboelectricity for Exoskeleton Robots

Robotic exoskeletons, which are wearable electromechanical devices that have been developed to support human movements, are attracting considerable attention in various fields, such as rehabilitation, military, leisure, and manufacturing fields. In this study, a self-energy harvesting composite structure was fabricated and applied to a lower limb exoskeleton robot as an ankle spring. The self-energy harvesting composite structure comprises carbon fiber reinforced plastics (CFRP) as conductive skins and aluminum amp; polytetrafluoroethylene (PTFE) as triboelectric cores. The output voltages of the self-energy harvesting composite specimens were analyzed according to various frequencies using a vibration shaker. Furthermore, self-energy harvesting composite springs were fabricated and mounted on the lower limb exoskeleton robot as ankle springs. Based on the running tests, we observed that the selfenergy harvesting composite springs of the lower limb exoskeleton robot could successfully harvest the electrical energy while storing and releasing elastic energy for assisting the human movement.