The goal of this research is to provide a low-frequency broadband energy harvester as a solution to the powering of wireless sensors for monitoring structures. Preliminary studies have demonstrated a mono-stable low-frequency energy harvester using diamagnetic levitation (DL). The key features of this energy harvester are its inherent nonlinearity, weak restoring forces and absence of mechanical friction. The proposed energy harvester is a bi-stable horizontal DL system which can undergo large periodic inter-well oscillations and chaotic motions from a range of input accelerations in all three directions. Hence this system can extract output power orders of magnitude more than traditional linear energy harvesters in a broadband frequency range. This research will also involve developing near-optimal and power management solutions for integrating the energy harvester with rechargeable batteries and laboratory tests of the prototypes will be performed to evaluate its performance in real ambient vibrations.
A promising high efficiency energy harvesting system with no apparent mechanical friction and a wide bandwidth in the low frequency range is envisioned to completely cater to the needs of energy harvesting for many engineering applications. Fundamental limits along with conflicting constraints imposed by the size of the harvester, transduction efficiency of the harvester and the energy available for the functioning of the structural health monitoring (SHM) systems will be addressed. A significant advancement in the knowledge of energy harvesting using nonlinear systems can be expected along with creating a framework for using DL in civil, mechanical, and aerospace engineering applications as an interest for systems with no mechanical damping persists for maximum efficiency. With the on-going advances in sensors and sensor network technologies, the proposed research will contribute greatly to the development of truly autonomous and self-sustained SHM systems for monitoring infrastructures.
