智慧型無線感測監控系統平臺建構與其在土木結構診斷應用之研究-總計畫暨子計畫:應用智能材料與微機電技術開發土木結構無線監測模組之獵能器與被動式無線感測器之研究(I)

Abstract

在結構健康監測時，傳統無線感測節點都需要裝設電池以提供能 量，但當感測器封裝於結構内部後，欲更換電池則是非常困難，為了減 少電池所導致的維護困難，使用不需電池的被動式無線感測器及能源擷 取器(獵能器）則成為結構健康監測所用智慧無線感測器網路的最新趨 勢。因此，本計畫規劃為三年期計畫，研究内容可分為三部分：1.能源 擷取器之研製，2.被動式無線感測器之研製，3.整合能源擷取器與被動 式無線感測器於智慧型無線監測系統平台與性能測試。

其中振動式能源擷取器會由本研究群已開發之變頻壓電能源擷取核 心技術，進一步應用複合式能源擷取之概念，將變頻壓電式與電磁式結 合，藉以研製變頻壓電/電磁複合式振動能源擷取器，不僅可更廣泛擷取 可用之環境能源，還能保有變頻機制使能源擷取器之共振頻率可與環境 振動頻率一致，進而產生最大功率輸出。再者，為了能夠廣泛地擷取空 間中各方向之振動能源，也將開發三維變頻壓電/電磁複合式能源擷取 器。被動式無線感測器部分，由於應變與振動是土木結構中最常監測的 物理量，本計畫將以先前開發高靈敏度電感電容迴路應變感測技術及電 容式微加速度技術為基礎，開發適合於土木結構監測的被動式電感電容 迴路無線感測元件，包含被動式無線應變計與被動式無線加速度計。由 於無需裝設電池於感測元件端，可安裝於不適合裝設電池的土木結構内 部，再搭配能源擷取器供應能量於結構外部的訊號讀取與處理模組，可 與智慧型無線監測系統平臺整合，利於電池維護及延長電池更換周期。

In conventional wireless structure health monitoring (SHM) net, each sensing node needs a battery. However, when the sensor needs to be embedded in the structure, battery maintenance or replacement becomes very difficult. Therefore, using passive wireless sensors and energy harvester in the sensing node become latest trend in wireless sensing net for SHM. This proposal is a three-year plan, and focuses on (1) development of energy harvester; (2) development of passive wireless sensor; (3) integration of energy harvester and passive wireless sensors to the wireless structure health monitoring (SHM) net.

For energy harvester, based on our previously developed piezoelectric vibration-based energy harvesting technology, hybrid type will be developed here by combining electro-magnetic and piezoelectric energy harvesting devices, as well as the 3D energy harvester to capture the multi ambient energy in the three dimensional space. For passive wireless sensors to monitor strain and vibration in structure, based on our previously developed high-sensitivity passive LC strain sensor and capacitive accelerometer, passive wireless strain sensor and passive wireless accelerometer will be developed by using LC circuit. Since battery does not need to be connected to the passive sensor, sensor can be installed in the structure without battery. By further combining with the energy harvester to provide extra power for the signal processing and storage module, the integration of passive wireless sensors and energy harvester in the wireless sensing node will be helpful in energy saving and battery maintenance.