A hybridized electromagnetic-triboelectric nanogenerator designed for scavenging biomechanical energy in human balance control

For human beings of different ages and physical abilities, the inherent balance control system is ubiquitous and active to prevent falling, especially in motion states. A hybridized electromagnetic-triboelectric nanogenerator (HETNG) is prepared to harvest biomechanical energy during human balance control processes and achieve significant monitoring functions. The HETNG is composed of a symmetrical pendulum structure and a cylinder magnet rolling inside. Four coils are divided into two groups which form into two electromagnetic generators (EMGs). Besides, two spatial electrodes attached to the inner wall constitute a freestanding mode triboelectric nanogenerator (TENG). With a rectification circuit, the HETNG presents a high output power with a peak value of 0.55 W at a load of 160 Ω. Along with human balance control processes during walking, the HETNG can harvest biomechanical energy at different positions on the trunk. Moreover, the HETNG applied in artificial limb has been preliminarily simulated with the positions on thigh and foot, for monitoring the actions of squat and stand up, and lifting the leg up and down. For the elder that walks slowly with a walking aid, the HETNG equipped on the walking aid can help to record the motions of forwarding and unexpected falling, which is useful for calling for help. This work shows the potential of biomechanical energy-driven HETNG for powering portable electronics and monitoring human motions, also shows significant concerns to people lacked action capability or disabled.