How to Screen Pendulum-Based Vibration Energy Harvester Studies

This does not mean rotary studies are irrelevant. They can explain how pendulum mechanisms extend into low-speed rotation or rotational-pendulum designs. The point is narrower: if the target device is governed by pendulum motion relative to a vibrating base, its main benchmark should be other pendulum-based vibration harvesters.

Papers that fit the main comparison table

The following candidates have titles or abstracts that explicitly place them in the pendulum, pendulum-like, mass-pendulum, or pendulum-composite family. They should still be grouped by structure, transducer type, and excitation before anyone compares output power.

Papers better handled as supplemental comparisons

Some studies include a pendulum idea but are not asking the same base-excited vibration-harvesting question. They are valuable, but they should not set the main performance benchmark unless the target review is also about rotary systems.

Why peak power alone is a weak ranking metric

Pendulum-based harvesters are highly sensitive to their motion boundary, transducer, and excitation. The candidate set already spans electromagnetic pendulums, pendulum arrays, low-frequency human-motion harvesters, inverted piezoelectric beam–pendulum structures, and piezoelectric–triboelectric hybrid pendulums . A single maximum-power value can therefore hide more than it reveals.

A stronger comparison table should extract these fields:

• Motion architecture: pendulum-like, dual-mass pendulum, pendulum array, inverted piezoelectric beam–pendulum, two-degree-of-freedom pendulum, or rotational pendulum-like structure .
• Transduction mechanism: electromagnetic, piezoelectric, or piezoelectric–triboelectric hybrid .
• Excitation condition: harmonic base excitation, low-frequency human motion, weak vibration, or low-speed mechanical rotation .
• Performance conditions: peak power, the frequency at which it was measured, input acceleration or displacement, load resistance, and test setup.
• Size and normalized data: mass, volume, power density, and output per unit mass, but only when the full text gives enough compatible data to calculate them.
• Response range: frequency–power curve, effective bandwidth, resonant modes, or dual-mode behavior. Devices with two degrees of freedom and two resonant modes especially need these conditions recorded .
• Special mechanisms: multidirectional harvesting, vibro-impact, bistability, or frequency-up conversion .

A practical table entry is: Pmax @ frequency / input / load / mass or volume. Peak power can be one field, but it should not be the headline ranking unless the testing conditions are genuinely comparable.

A workable search and screening order

Start with pendulum-based vibration energy harvesting to build the core set, since the topic has already been organized in dedicated review literature . Then expand with structure-specific keywords such as pendulum-like electromagnetic, dual-mass pendulum, inverted piezoelectric beam and pendulum, piezoelectric-triboelectric pendulum, and frequency-up conversion pendulum.

A defensible screening workflow is:

1. Screen titles and abstracts for the pendulum mechanism. Prioritize records that explicitly include pendulum, pendulum-like, mass-pendulum, or a pendulum-composite structure .
2. Classify the motion boundary. If the study is about base excitation or low-frequency vibration input, keep it in the main table. If it is mainly about low-speed rotation or a rotational pendulum, move it to the supplemental table .
3. Read the full text before making performance claims. Extract peak power, frequency, input excitation, load resistance, device mass, volume, and bandwidth from the paper’s figures, tables, and experimental description.

The safe writing boundary

The available titles and abstracts are enough to justify the screening logic: pendulum-based vibration energy harvesting is a recognized review category , and the candidate records cover electromagnetic pendulums, pendulum arrays, low-frequency human-motion harvesters, piezoelectric beam–pendulum systems, and piezoelectric–triboelectric hybrid pendulum devices .

They are not enough to rank performance. In a formal review, avoid saying that one paper is stronger than another based only on a title, abstract, or isolated peak-power number. The most reliable structure is to make pendulum-based studies the main comparison group, place rotary transition mechanisms in a supplemental group, and state performance conclusions only after the full-text conditions have been normalized.