Table 3.
Summary of reported typical tuning approaches for cantilever-based energy harvesters including resonance-based tuning and expanded bandwidth methods.
| Resonance-based tuning methods | |||||
|---|---|---|---|---|---|
| Reference | Frequency tuning methods | Untuned frequency [Hz] | Tuning range [Hz] | Tuning load (force/displacement) | Power output [μW] |
| Gieras et al.[127] | Changing geometry | – | – | – | – |
| Wu et al.[128] | – | 130–180 | 21 mm | – | |
| Zhu et al.[72] | Magnetic stiffness | 45 | 67.6–98 | 3.8 mm | 61.6–156.6 |
| Challa et al.[137] | 26.2 | 22–32 | 3 cm | 240–280 | |
| Dong et al.[138] | 61 | 51–87 | 12.7 mm (trans) | – | |
| 10.16 mm (axial) | |||||
| Peters et al.[139] | Piezoelectric stiffness | 78 | 66–89 | ±5 V | – |
| Wischke et al.[140] | 299 | 275–300a) | −65 to 130 V | – | |
| Scheibner et al.[141] | Electrostatic stiffness | 3.66k | 1.41–3.66k | 32.5 V | – |
| Lee et al.[142] | 19k | 8.45–19k | 150 V | – | |
| Expanded bandwidth methods | ||||
|---|---|---|---|---|
| Reference | Expanding bandwidth | Number of cantilevers | Tuning range [Hz] | Power [μW] |
| Berkcan et al.[144] | Multiple structures | 4 | 100–900a) | – |
| Xue et al.[146] | 10 | 92–110 | 40–140 | |
| Lee and Kim[147] | 5 | 59.8–62.6 | 0.9–1.6 | |
| Burrow and Clare[150] | Nonlinear (stiffness) | Better performance at excitation frequencies higher (lower) than resonant frequency, but complexity in design | ||
| Mann and Sims[152] | ||||
| Zhang[151] | ||||
| Cottone et al.[155] | Nonlinear (bistable) | |||
a)
Estimated data from the reference.