CAREER: A Universal Microsystem-based Vibration Energy Harvester

该项目由电气、通信和网络系统（ECCS）和促进竞争研究的既定计划（EPSCoR）共同资助。随着对物联网、网络物理系统和智能建筑的需求不断增长，无线传感器网络将大幅增加，所有这些都需要电力来运行。然而，电池有一个有限的寿命，因此有必要创造一个自我维持的系统，可以从周围环境中收集能量，而不需要电池。基于振动的能量采集器具有全天候工作的优势，可以应用于几乎所有的应用。基于微系统的能量收集器具有小型和低成本等优点，但是存在许多限制其成功的挑战。本研究将探讨解决这些挑战和克服限制的方法。本研究的目标是创建一个通用的低频微系统振动能量收集系统，为这些无线传感器网络供电。所研究的解决这些挑战的方法有可能应用于其他微系统应用，以提高传感器或致动性能。该项目将对社会和科学界产生影响。此外，该项目旨在通过针对本科生和K-12学生的跨学科STEM教育外展计划提高对微系统的认识。该项目将开展外展活动，向代表性不足的学生推广微系统和STEM教育。微系统的研究是跨学科的，包括所有STEM学科。该项目的教育目标是提高人们对微系统的认识，以及它们如何影响我们的日常生活，以激励下一代科学家和工程师。在过去的十年中，微系统振动能量采集器已经得到了广泛的研究，但由于其微尺度和作用机制的限制，限制了系统在实验室环境中的进展。目前有四大挑战限制了它们的使用：1)狭窄的频率带宽，2)缺乏频率可调性，3)低功率密度，以及4)可靠性。本研究将研究和开发新的设计和微加工方法来解决这些挑战。该项目的研究目标是通过结合新颖的集成和驱动机制来提高低频低加速度压电微系统能量采集器的功能，以i)拓宽带宽，ii)进行大范围的主动/被动频率调谐，以及iii)使用新型功能薄膜材料结构提高功率密度。每个组件都将单独设计和表征，然后集成在一起开发一个完整的通用系统，可以克服当前与微尺度振动能量采集器相关的挑战。非线性动力学机制，以扩大带宽而不显着降低功率使用单片集成的可移动的证明将被研究。这将导致无源宽带系统，不需要任何额外的功耗。频率调谐将使用一种新的质量负载分配方法进行研究，该方法可以被动地提高器件的可制造性，并促进微系统的批量制造优势，以获得适用于多种应用的通用低频系统（250 Hz）。研究了一种基于质量负载分布的主动调谐机制，目标频率范围为200hz，分辨率为1hz。通过提高三元氮化薄膜的材料性能，开发新的极性控制压电结构，可以提高功率密度。集成这些方法来创建一个单片一体化系统需要新的微加工方法，这些方法将被开发出来，并可以应用于未来的微系统应用，而不仅仅是能量采集器。该奖项反映了美国国家科学基金会的法定使命，并通过使用基金会的知识价值和更广泛的影响审查标准进行评估，被认为值得支持。

This project is jointly funded by the Electrical, Communications and Cyber Systems (ECCS) and the Established Program to Stimulate Competitive Research (EPSCoR). With the growing demand for the Internet of Things, Cyber Physical Systems, and Smart Buildings there will be a significant increase in wireless sensor networks, all of which will require power to operate. However, batteries have a limited lifetime, therefore there is a need to create a self-sustaining system that can harvest energy from the ambient environment without the need of batteries. Vibration-based energy harvesters have the advantage of functioning 24/7 and can be applied to almost all applications. Microsystems-based energy harvesters have advantages such as small-scale and low cost, but there are numerous challenges which have limited their success. This study will investigate methods to solve those challenges and overcome the limitations. The goal of this study is to create a universal low-frequency microsystem vibration energy harvesting system to power these wireless sensor networks. The investigated methods to solve these challenges have potential to be applied to other microsystem applications to enhance sensor or actuating performance in the future. The project will impact society as well as the scientific community. In addition, this project aims to increase awareness of microsystems through an interdisciplinary STEM education outreach program directed at undergraduate and K-12 students. The program will develop outreach events to promote microsystems and STEM education to underrepresented students. The study of microsystems is interdisciplinary consisting of all STEM disciplines. The educational goal of this project is to increase awareness of microsystems and how they impact our daily lives to inspire the next generation of scientists and engineers. Microsystem vibration energy harvesters have been extensively investigated over the past decade but limitations due to their micro-scale and mechanisms of actions have limited the systems from progressing past the lab environment. There are four grand challenges that currently limit their use: 1) narrow frequency bandwidth, 2) lack of frequency tunability, 3) low power density, and 4) reliability. This study will investigate and develop novel designs and microfabrication methods to address these challenges. The research objective of this project is to enhance functionality of a low frequency low acceleration piezoelectric microsystem energy harvester by combining novel integration and actuation mechanisms to i) widen the bandwidth, ii) perform wide range active/passive frequency tuning, and iii) enhance power density using novel functional thin film material structures. Each component will be designed and characterized individually and then integrated together to develop a complete universal system that can overcome the current challenges associated with micro-scale vibration energy harvesters. Non-linear dynamics mechanisms to widen the bandwidth without significant decrease in power using monolithically integrated movable proof-mass will be investigated. This will result in a passive wide bandwidth system that does not require any additional power consumption. Frequency tuning will be investigated using a novel mass load distribution method that can be passive to increase manufacturability of the devices and promote batch fabrication advantages of microsystems to obtain a universal low-frequency system for multiple applications (250 Hz). An active tuning mechanism based on mass load distribution with a targeted frequency range of 200 Hz with a resolution of 1 Hz will also be investigated. Power density will be enhanced by developing new polarity controlled piezoelectric structures by enhancing material properties of ternary nitride thin films. Integration of these methods to create a monolithic all-in-one system requires novel microfabrication methods which will be developed and can be applied to future microsystem applications beyond energy harvesters.This award reflects NSF's statutory mission and has been deemed worthy of support through evaluation using the Foundation's intellectual merit and broader impacts review criteria.