• Declan O'Donoghue
  • Frizzell R.
  • Jeff Punch
  • Kelly G.
  • Valeria Nico

Vibrational energy harvesting has become relevant as a power source for the reduced power requirement of electronics used in wireless sensor networks (WSNs). Vibrational energy harvesters (VEHs) are devices that can convert ambient kinetic energy into electrical energy using three principal transduction mechanisms: piezoelectric, electromagnetic and electrostatic. In this paper, a macroscopic two degree-of-freedom (2Dof) nonlinear energy harvester, which employs velocity amplification to enhance the power scavenged from ambient vibrations, is presented. Velocity amplification is achieved through sequential collisions between free-moving masses, and the final velocity is proportional to the mass ratio and the number of masses. Electromagnetic induction is chosen as the transduction mechanism because it can be readily implemented in a device which uses velocity amplification. The experimental results are presented in Part A of this paper, while in Part B three theoretical models are presented: (1) a coupled model where the two masses of the non-linear oscillator are considered as a coupled harmonic oscillators system; (2) an uncoupled model where the two masses are not linked and collisions between masses can occur; (3) a model that considers both the previous cases. The first two models act as necessary building blocks for the accurate development of the third model. This final model is essential for a better understanding of the dynamics of the 2-Dof device because it can represent the real behaviour of the system and captures the velocity amplification effect which is a key requirement of modelling device of interest in this work. Moreover, this model is essential for a future optimization of geometric and magnetic parameters in order to develop a MEMS scale multi-degree-of-freedom device.

Recent Publications

August 09, 2017

A Cloud Native Approach to 5G Network Slicing

  • Francini A.
  • Miller R.
  • Sharma S.

5G networks will have to support a set of very diverse and often extreme requirements. Network slicing offers an effective way to unlock the full potential of 5G networks and meet those requirements on a shared network infrastructure. This paper presents a cloud native approach to network slicing. The cloud ...

August 01, 2017

Modeling and simulation of RSOA with a dual-electrode configuration

  • De Valicourt G.
  • Liu Z.
  • Violas M.
  • Wang H.
  • Wu Q.

Based on the physical model of a bulk reflective semiconductor optical amplifier (RSOA) used as a modulator in radio over fiber (RoF) links, the distributions of carrier density, signal photon density, and amplified spontaneous emission photon density are demonstrated. One of limits in the use of RSOA is the lower ...

July 12, 2017

PrivApprox: Privacy-Preserving Stream Analytics

  • Chen R.
  • Christof Fetzer
  • Le D.
  • Martin Beck
  • Pramod Bhatotia
  • Thorsten Strufe

How to preserve users' privacy while supporting high-utility analytics for low-latency stream processing? To answer this question: we describe the design, implementation and evaluation of PRIVAPPROX, a data analytics system for privacy-preserving stream processing. PRIVAPPROX provides three properties: (i) Privacy: zero-knowledge privacy (ezk) guarantees for users, a privacy bound tighter ...