射出成形製程監測之自發電無線感測模組研發及其關鍵元件-溫度/壓力複合式微感測器之設計製作

Abstract

近年來由於節能環保議題的盛行，因此能源擷取技術(Energy Harvesting)快速發展；而無線感測網路則是已經被廣泛的使用(Wireless Sensors Network, WSN)。結合此兩項技術因而發展智慧型節能無線感測網路，此一技術可由大型工具機或者工作環境中回收能量使用，除減少能源消耗外更甚者可以達到永續利用之效果可以克服無線感測網路必須頻繁更換電池之問題，成為無線感測網路解決能量問題的另一方案。 本研究利用熱-電轉換機制由射出成形機回收廢熱使用，並進一步整合出一個具備自身發電能力的無線感測模組；成功監測射出成形加工時模內溫度之變化；除溫度外亦進行了壓力監測，但由於雜訊過大之問題仍無法克服，因此僅確認此實驗架構之可行性。除此外，針對無線感測模組之韌體進行修改，大幅提升了無線感測模組之訊號傳輸能力，但由於高傳輸效率之無線感測模組耗電量也同時上升，雖仍小於其他無線傳輸協定，但以目前所用之熱電回收系統仍無法滿足此一需求，但已為未來對於傳輸速率有較高需求之使用者預見了另一可能性。最後，自行設計一可同時監測壓力與溫度之複合式感測元件並利用微機電製程技術(MEMS)製作，目前已完成最關鍵之電磁訊號發送元件並成功量測訊號。

Recently, energy-harvester-powered (i.e., self-powered) wireless sensors network for environmental, medical, mechanical, and civil structural monitoring applications are rapidly developed. In this thesis, an energy-harvester-powered (i.e., self-powered) wireless sensing module for injection-molding monitoring is reported. Thermoelectric generators connected in series are used to harness a thermal energy from the injection-molding process and subsequently convert the thermal energy to the electrical output. The electrical output is consequently modulated/rectified to power a customized wireless temperature-sensing module which consists of wireless RF components, central controlling unit, RTD temperature sensor (embedded inside a mold cavity to detect the process temperature of injection-molding), and corresponding circuits. Due to this, a self-powered wireless temperature sensing module for injection-molding monitoring is achieved. The experimental results show the module successfully monitors the process temperature of the injection-molding. In addition, a smart MEMS temperature/pressure-hybrid sensor is fabricated and integrated with the module toward an intelligent injection-molding monitoring module. The testing results indicate the intelligent module is capable of sensing the temperature and pressure in the injection-molding process.