技術探索

高可靠度現場無線感測網路系統技術

中文摘要

工廠現場即時監控是提升生產管理與產品品質的重要利器,而傳統的有線網路監控系統成本高且佈線不易,不利於中小型或運行中的工廠,因此無線工業感測網路逐漸成為智慧工廠未來主流。然工廠環境中充斥著作業人員與運輸機具移動造成訊號受阻隔而衰減、混雜的無線干擾(例如:無線對講機、馬達運轉所衍生的寬頻雜訊等)、或是機台林立而造成多路徑效應等問題,對於無線傳輸可靠度影響甚鉅。再者無線網路頻寬與時序同步能力遠不如有線網路,面對工廠多元化傳輸需求,將是一大挑戰。總而言之,無線網路在工廠實務應用上仍未能全然滿足設備干擾、資料同步與服務品質等需求。
  本計畫設計發展之高可靠度現場無線感測網路系統提供感測資料收集應用,本系統主要包含三個部分:mote感測節點、網路管理器、以及行動監控平台。感測節點mote裝置以IEEE 802.15.4e自動形成感測叢集,並傳送與接收資料至所屬的網路管理器。網路管理器管理其感測叢集內的mote節點,同時與其他網路管理器形成WiFi mesh網路骨幹,將資料收即至後台。行動監控平台Mobile Dashboard則提供Web-based場域編輯工具與感測網路監控工具便於佈建及監控人員掌控狀況。
  本系統經工廠實地佈建測試驗證,情境包含(一)跨越實體阻隔收集機台定點多樣態感測資料;(二)跨廠區移動載具之資料收集。測試結果顯示WiFi mesh以hopping可跨越阻隔及連結廠區且可傳輸速度亦滿足資料收集需求,驗證本系統於工廠生產管理資料收集應用的有效性,且於網路佈建具有機動性及擴充性。未來系統將朝向各特定應用之服務品質發展,提供產業升級更好的輔助工具。

Abstract

Monitoring system is important for production management and quality control. Wired solutions are high cost and the cabling installations are inconvenience. Hence, wireless sensor network solution has become a new trend in intelligent factories. However, due to the combined effects of signal attenuation, noise and multipath induced by machines, personnel or vehicles, the transmission of wireless networks might be not reliable as wired networks. It is also a challenge by using wireless network solutions to satisfy the various transmission requirements in factories, due to the limited bandwidth and poor capability of time-synchronization. As a result, there are several issues such as, interfere, data synchronization, Quality of Service (QoS), have to be overcome in real cases.
In this project we developed a high reliability field wireless sensor network system for data collection. This system includes three parts: mote, network manager and mobile dashboard. Mote is sensor embedded network device, built with IEEE 802.15.4e communication protocol and in charge of sending sensor data to its belonging network manager. Network Manager is a hardware device built with Wi-Fi and IEEE 802.15.4e communication protocols that are used to corporately collect sensor data from the motes and send to management server. Mobile Dashboard is an application with graphical user interface that user can easily arrange sensor network hardware and monitor them.
The system has been verified in two factories. In case 1, there are obstacle in the environment; in case 2, the mobile carrier with sensor node moved in two zones. The results show WiFi mesh network are constructed through hopping to overcome constrained environments, and the data rates fulfil the requirements. It shows the efficiency of our system in filed network for sensor data collection. In the future, the QoS issues will be improved for specific applications.

關鍵詞(Key Words)

感測網路(Sensor Network)
感測節點(Mote)
網路管理器(Network Manager)
行動監控平台(Mobile Dashboard)

相關檔案: 高可靠度現場無線感測網路系統技術(全文)