A wearable self-powered sensor for upper limb motion monitoring via a coupled dual-piezoelectric-inertial pendulum structure

Abstract In this study, an upper limb wearable piezoelectric motion detection sensor (WSPI) based on a double piezoelectric plate-inertial pendulum coupling structure is proposed to meet the needs of human motion monitoring. At the heart of the unit is the piezoelectric unit, consisting of two rectangular piezoelectric ceramic sheets placed opposite each other at specific vertical angles. The movement of the human arm drives the inertial pendulum to periodically hit the bottom end of the piezoelectric plate, so that the piezoelectric plate can be bent and deformed efficiently, and then generate electrical energy. A series of experiments show that the prototype exhibits the best output performance under the assembly condition of two rectangular piezoelectric elements with a mounting angle of 35° and a fixed inertia pendulum height of 25 mm from the top. The unit has a maximum voltage of 151 V and a maximum output power of 194 mW. A series of application experiments were carried out to verify the electrical output performance, power supply capability and motion detection capability of the device. The design of WSPI provides a more efficient and accurate solution for the development of self-powered technology for smart wearable devices.