動態網路控制系統之時間延遲分析

Abstract

近年來，網路在工業上的應用越來越多，由於網路化可以帶來許多優點，比如說減省配線，減少安裝和維護的成本，和增加監控和控制的距離等，所以，網路控制系統慢慢也成為一種趨勢。 在建構CAN網路方面，我們開發了一套CAN網路監控系統，可以在開發CAN網路的時候方便網路的監控和除錯。本論文整合了Ethernet和CAN兩種不協定的網路，建立一個網路控制系統平台，在遠端經由個人電腦，透過可讓TCP/IP和CAN兩種協定互相轉換的gateway，成功的控制由微控器和AC伺服馬達組成的馬達遠端監控系統。 在網路控制方面，本研究透過實驗來量測客戶端到馬達系統間應用層到應用層的平均延遲時間。藉由實驗的分析，可以發現不同的取樣週期和控制環境皆會對延遲時間造成影響。在實驗中也發現距離因素不會影響延遲時間。隨著取樣時間減少和系統傳輸量增加，網路延遲時間也會慢慢跟著增加。在無線網路下所量測的平均延遲時間，會因環境干擾所造成延遲時間的突發性增加。但在經過處理後，可以取得較準確的延遲時間。本研究成功的設計史密斯估測器(Smith predictor)，可從遠端建立監控系統，並實際成功的測試了由高雄控制交大實驗室中的伺服控制系統。

To construct a remote control system, a monitoring system has been developed as a platform in this study to debug the CAN network system. Furthermore, both the industrial network CAN and the commercial networks, the Ethernet and the 802.11, have been integrated as network control systems (NCSs). By applying the TCP/IP as the gateway between different networks, an AC servo motor with different networks (a) the Ethernet and the CAN and (b) the wireless 802.11 and the CAN have been established and tested. The time delay between the application layer of the client and the application layer of the remote control target has been measured, analyzed, and processed through experiments. Results of the Ethernet and the CAN system indicate that different sampling periods and environments greatly affect the delayed time. Moreover, the distance has insignificant effect on the time delay of the NCS. In the wireless network environment, time delay may suddenly increases due to its environment disturbance. In the present NCS with the wireless system, the measured time delay processed by eliminating all sudden change values leads to significantly improved results of NCS. Finally, to verify the proposed NCS with a serious time delay, a remote control system by including the Smith predictor has been successfully applied to control a servo motor system form Kaohsiung to the laboratory in Nation Chiao-Tung University to verify the feasibility of the proposed systems.