A nonlinear energy harvester operated in the stochastic resonance regime for signal detection/measurement applications

An energy harvester can operate as a sensor. This article investigates the behavior of a snap-through buckling beam, which underpins a nonlinear vibrational energy harvester (NLEH), in the presence of noisy vibrations superimposed on a subthreshold deterministic input signal. In particular, we concentrate on a specific operating regime, in which noise-mediated cooperative behavior, specifically 'stochastic resonance' (SR), can be exploited in signal detection scenarios. We consider a sinusoidal signal with amplitude below the switching threshold of the NLEH, i.e., the signal alone does not lead to switching between the stable states of the NLEH. As expected, there exists an optimal noise intensity at which the response signal-to-noise ratio (SNR) passes through a maximum, the hallmark of the SR effect. The harvesting performance, quantified by the generated electrical power and the mechanical-electrical conversion efficiency, is examined as a function of the amplitude/frequency of the deterministic signal, and the noise intensity. Realizing that both the SR effect and the most efficient energy-harvesting (EH) behavior depend on the rate of switching events across the energy barrier of the device, we find that 'tuning' to the SR regime does, in fact, improve signal detection, as should be expected. However, the EH performance improves with larger noise values. Therefore, the regimes for optimal signal detection and highest electrical power generation are different, with increasing noise intensity yielding better EH performance. There does exist, however, the intriguing possibility that, by carefully configuring the electrical stage of the NLEH, one could realize an autonomous sensor that collects electrical power to charge a capacitor and utilizes it to power the electronics for signal detection/analysis in the SR regime.