Mesoscale Transduction Systems And Applications To Energy Harvesting Onboard Flying Insects

Abstract

We begin this dissertation first by defining the mesoscale as the realm of feature sizes that span from the single micron to the centimeter range. The motivation for focusing on the mesoscale is that in terms of today's power applications, such geometric scale is required in order to allow for sufficient energy transduction within the larger devices that they serve. Thus, by further developing the models and fabrication techniques within the mesoscale, this collection of works aims to achieve a direct and immediate impact on advancing the state of the art within these facets of transduction technology. The first chapter of this dissertation describes the derivation and first known experimental validation of a generalized analytical method for predicting the performance of a piezoelectric vibration energy harvesting devices with geometric discontinuities. Here we adapt the transfer matrix method to incorporate the direct piezoelectric effect, thereby predicting the electromechanical response of such devices. The significance of this work is that it a means to progress away from geometry specific solutions to a generalized analytical approach for design. The next chapter describes the results of a fan-folded, i.e. discontinuous geometry, piezoelectric structure attached to a Manduca sexta hawkmoth. Here the design criteria are developed through empirical studies of insect's abilities and by the power requirements of the proposed miniaturized onboard devices. The significance of this work is that it provides the first known successful demonstration of in-situ harnessing of free, flapping flight on an insect capable of powering technology such as radio transmissions. The third chapter details the use of single-level lithography to simplify the microfabrication of stacked inductors used in power converter technology. By using such a technique and increasing the scale to the mesoscale range, the inductance of such devices can be increased to the necessary micro-Henry inductance level. The fourth chapter describes the full conduction, convection, and radiation modeling of the classic thermal micro-actuator. Within this model, we extend beyond the conventional conduction-only approach to yield more accurate models and transfer functions needed for advancing controls applications in microscale technology.