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

该研究项目旨在研究用于事件时间戳和事件重建的自供电传感设备、电路和算法。作为一项概念验证，我们正在将这些技术应用于设计无源、无电池结构健康监测（SHM）传感器，这些传感器可以连续感知和记录在结构使用寿命期间可能发生的重要和罕见事件。例如，在骨科植入物中，如膝关节或髋关节植入物，使用这些技术将能够传达关于任何机械错位或植入物任何异常使用的时间信息。这些信息对外科医生的诊断和任何翻修手术的计划都是有用的。对于民用和航空航天结构，这些技术可用于确定结构何时遭受大的机械变形或应变；或者当一个罕见的，不必要的机械冲击与结构可能发生时。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，提出的自供电传感技术可能是实现物联网宏伟愿景的关键推动者，在物联网中，数百万无源、廉价的传感器可能成为“智能”结构（民用、航空航天、机械和生物力学）的组成部分，这些结构可以自我诊断自己的灾难性故障。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；包括自供电传感器领域的教学模块的设计和教程和专题会议的组织。此外，除了指导研究生和本科生外，该项目还在传感器和结构健康监测领域促进学生创业活动。提出的研究的智力价值在于研究热力学和量子力学驱动的电子传递现象，这些现象可用于实现永久计时器和时钟。正在研究不同的器件和布局拓扑结构，这将导致具有不同动态响应的计时器和可以在整个监测期间连续运行的计时器。将计时器的物理特性与压电驱动的冲击电离热电子注入过程的物理特性相结合，当传感器嵌入或植入机械活性结构中时，实现对机械应变的自供电监测。利用这些时间调制的热电子注入器阵列，该项目正在研究稀疏重建算法，该算法将能够对显著的应变相关事件进行时间戳。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标准CMOS工艺中进行原型设计，并与先前开发的射频识别（RFID）和无线传感片上系统架构集成。这种混合能量清除配置不仅可以实现对突出事件和罕见事件的连续、自供电监测，还可以实现传感器数据的无线检索，以及在用户命令和控制下对传感器进行远程初始化和配置。

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.