Scavenging Thermal-noise Energy and Quantum Fluctuations for Self-powered Time-stamping and Sensing

本研究项目是研究用于事件时间戳和事件重建的自供电传感装置、电路和算法。作为一项概念验证，我们正在应用这些技术来设计无源、无电池的结构健康监测(SHM)传感器，这些传感器可以连续感知在结构使用寿命期间可能发生的重要和罕见事件并对其进行时间标记。例如，在像膝盖或髋关节植入物这样的骨科植入物中，这些技术的使用将能够传达关于任何机械未对准或植入物的任何异常使用的时间信息。这些信息对外科医生诊断和计划任何翻修手术都是有用的。对于民用和航空航天结构，这些技术可以用来确定结构何时遭受大的机械变形或应变；或者何时可能发生罕见的、不必要的结构机械冲击。与计算机模型相结合，带有时间戳的事件信息可用于预测即将发生的故障，并可用于确定基于状态的维护计划。因此，拟议的自给式传感技术可能是实现物联网宏伟愿景的关键促进者，在物联网中，数百万无源、廉价的传感器可能成为能够自我诊断自身灾难性故障的“智能”结构(民用、航空航天、机械和生物力学)的组成部分。作为外联活动的一部分，该项目正在开发电气、结构和生物医学工程师之间的跨学科论坛；并包括设计教育单元和组织自给传感器领域的辅导和特别会议。此外，除了对研究生和本科生的指导外，该项目还在传感器和结构健康监测领域培养学生创业活动。拟议研究的智力价值在于调查热力学和量子力学驱动的电子传输现象，这些现象可以用来实现永久计时器和时钟。正在研究不同的器件和布局拓扑，这将导致定时器具有不同的动态响应，并导致定时器可以在整个监控周期内连续运行。定时器的物理与压电驱动的碰撞电离热电子注入过程的物理相结合，以实现当传感器嵌入或植入机械主动结构中时的机械应变的自给能监测。利用这些定时调制的热电子注入器阵列，该项目正在研究稀疏重建算法，这些算法将能够对显著的应变相关事件进行时间标记。作为概念验证，实现自供电定时器和自供电应变传感器的电路正在以标准的cmos工艺制作原型，还将与以前开发的射频识别(RFID)和无线传感系统片上架构集成在一起。这种混合能量清除配置不仅可以对显著和罕见事件进行持续、自给电源的监控，还可以在用户的命令和控制下远程初始化和配置传感器数据，并实现传感器数据的无线检索。

This research project is investigating self-powered sensing devices, circuits and algorithms for event time stamping and event reconstruction. As a proof-of-concept we are applying these techniques for designing passive, battery-less structural health monitoring (SHM) sensors that can continuously sense and time-stamp important and rare events that could have occurred during the operating life span of the structure. For instance in orthopedic implants like knee or hip implants, the use of these techniques would be able convey temporal information about any mechanical misalignment or any abnormal usage of the implant. This information could be useful to surgeons in diagnosing and planning of any revision surgery. For civil and aerospace structures, these techniques could be used to determine when the structure was subjected to large mechanical deformations or strains; or when a rare, unwanted mechanical impact with the structure could have occurred. In combination with computer models, the time-stamped event information could be used in prognosticating impending failures and can be used in determining condition-based maintenance schedules. Thus, the proposed self-powered sensing technology could be a key facilitator in achieving the grand vision for the internet-of-things, where millions of passive, inexpensive sensors could become an integral part of "smart" structures (civil, aerospace, mechanical and biomechanical) that can self-diagnose its own catastrophic failure. As a part of the outreach activities, the project is developing a cross-disciplinary forum between the electrical, structural and biomedical engineers; and includes design of educational modules and organization of tutorial and special sessions in the area of self-powered sensors. Also, in addition to the mentoring of graduate and undergraduate students, the project is also fostering student entrepreneurship activities in the area of sensors and structural health monitoring.The intellectual merit of the proposed research lies in the investigation of thermodynamically and quantum-mechanically driven electron transport phenomena that can be used to implement perpetual timers and clocks. Different device and layout topologies are being investigated that will lead to timers with different dynamical responses and to timers that can continuously operate over the entire monitoring period. The physics of the timer is being combined with the physics of the piezoelectricity driven impact-ionized hot-electron injection process to achieve self-powered monitoring of mechanical strain when the sensor is embedded or implanted inside a mechanically active structure. Using an array of these timer-modulated hot-electron injectors, the project is investigating sparse reconstruction algorithms that will be able to time stamp salient strain-related events. As a proof-of-concept, the circuits implementing the self-powered timers and the self-powered strain sensors are being prototyped in a standard CMOS process are also being integrated with previously developed radio-frequency identification (RFID) and wireless sensing system-on-chip architectures. This hybrid energy scavenging configuration will not only enable continuous, self-powered monitoring of salient and rare events but will also enable wireless retrieval of the sensor data along with remote initialization and configuration of the sensor under user command and control.