LAUSR

Abstract Strategies for the energy harvesting of low-frequency vibration modes such as sphygmus and human body motions are immature due to the rigorous resonance issue. Stochastic resonance seems to be an appropriate solution to the energy harvesting of low-frequency vibrations. This paper presented the mathematical model of piecewise bistable energy harvesters and solved numerically. Taking the piecewise slope into consideration, the Kramers rate and signal to noise ratio (SNR) of piecewise bistable systems were studied, and the effects of piecewise slope on dynamic output characteristics of piecewise bistable energy harvesters were analyzed. The effect of load resistance on the efficiency of energy harvesting of piecewise bistable energy harvesters compared with their counterparts is evaluated. Furthermore, the influences of ambient periodic excitation and additive noise on the energy harvesting performance of piecewise bistable energy harvesters were investigated. Additionally, the evaluation of piecewise bistable energy harvesters using the measured input signal was completed. The numerical simulations indicate that piecewise bistable energy harvesters with small piecewise slope make great contributions to the enhancement of SNR and energy harvesting; the increases in resonant amplitude of ambient periodic excitation or additive noise intensity cause the transition from monostable to bistable, and piecewise bistable systems with smaller piecewise slope have larger unsaturation for ambient energy harvesting. The maximum electric power can be achieved by using optimal load resistance which can be identified numerically. The evaluation of piecewise bistable energy harvesters by employing the measured input signal shows that piecewise bistable energy harvesters with small piecewise slope perform satisfactory under ultra-low frequency excitation.