Multiple directional energy harvesting

Multiple directional energy harvesting -- cantilever-pendulum with 1:2 internal resonance

the first multiple directional harvester by a single cantilever

The cantilever pendulum system is based on a single piezoelectric cantilever with a pendulum connected to its tip. The piezoelectric cantilever beam has a piezoelectric transducer bonded near the root. The pendulum is formed by a sphere-shaped mass and a wire which is considered massless and tensioned.

Underlying physics: In one cycle of the pendulum resonant motion, the centripetal acceleration projection to z-axis due to pendulum motion has periodically varied two cycles.

1. Excitations with multiple frequencies, voltage output at a single frequency.

2. Excitations from multiple directions, voltage output by a z-direction beam bending motion;

Multi-directional input induce single direction beam bending motion.

Efficient energy generation under an arbitrary direction excitation.

Key advantages:

1. harvest vibration energy in arbitrary direction;

2. broadband effect from 1:2 internal resonance;

3. frequency doubling effect, frequency up conversion.

Publications:

* J. Xu and J. Tang, “Modeling and Analysis of Piezoelectric Cantilever-Pendulum System for Multi-directional Energy Harvesting,” Journal of Intelligent Material Systems and Structures, 2016. (Special issue)

* J. Xu and J. Tang, “Multi-Directional Vibration Energy Harvesting by Internal Resonance,” Applied Physics Letters, 107(21), 2015.

* J. Xu and J. Tang, “Piezoelectric cantilever-pendulum for multi-directional energy harvesting with internal resonance,” Proc. SPIE, Active and Passive Smart Structures and Integrated Systems, 2016.