An elliptical rail–mass–spring mechanism to realize multi-stable circulation motion for electromagnetic-energy harvesting

This study proposes an elliptical rail–mass–spring mechanism to realize multi-stable circulation motion for electromagnetic energy harvesting. Unlike the conventional bistable vibration model, the moveable body can jump between multiple potential energy wells. Correspondingly, the elliptical rail–mass–spring prototype is deliberately exploited, and experimental investigation indicates that the response angular displacement range of the moveable body can be expanded to [0°–630°] as a circulation elliptical motion and the response angular displacement range can be expanded if the low-frequency vibrational excitation is continued. Comparing the average power obtained by the elliptical rail–mass–spring mechanism, 17.33 mW was obtained for the random signal, 45.40 mW was obtained for the periodic signal with the largest motion response of 0.8 Hz, and 77.99 mW was obtained when the two signals were combined. The average power obtained by a combined signal is greater than the sum of the results obtained by a separate signal, which confirms that the elliptical rail–mass–spring mechanism noticeably enhances power-generation efficiency.