適用於網際網路控制系統之流量控制演算法設計

Design of Flow Control Algorithm for Internet-based Networked Control Systems

葉子源(Tz-Yuan Ya)

指導教授 ： 曾傳蘆

國立臺北科技大學/機電學院/電機工程系所/碩士(2006年)

摘要

透過網際網路傳送資訊或進行控制，不僅可以降低線路的複雜度並且可以進行遠距操控，所以網際網路控制系統(Internet-based Networked Control System, INCS)應用受到越來越多的重視，但因為網際網路傳送資料時會有傳輸延遲現象，在系統設計上必須考慮其延遲的特性。
有鑑於此，本論文在比較傳輸控制協定(Transmission Control Protocol, TCP)、使用者資料段協定(User Datagram Protocol, UDP)與最近提出的控制系統傳輸協定(Control System Transfer Protocol, CSTP)等傳輸協定的優缺點後，提出一個適用於網際網路控制系統資料傳輸的新型模糊流量控制演算法。由於網路傳輸會因時間、地點的不同，所得到的網路狀態也會有所不同，因此所提流量控制演算法結合基因演算法與模糊控制法則，可隨網路狀態，例如網路來回時間(Round Trip Time, RTT)及其變動量，改變傳送端的封包傳送率，使資料傳送端具有即時自我調整的流量控制功能。
最後，本論文整合網路模擬軟體NS2與控制模擬軟體MATLAB為模擬平台，進行網際網路控制系統的模擬。由模擬所得到的數據，可知本論文所提出之流量控制機制能使網路控制系統之網路傳輸延遲量減小，傳輸封包延遲較具均一性，並可提高控制系統的穩定性，使整個閉迴路系統有更好的動態特性。

關鍵字

網際網路 ； 流量控制 ； 基因演算法 ； 網際網路控制系統

並列摘要

Using Internet to deliver information or control message can not only reduce the complexity of wire lines but also allow for carrying out the remote control. Consequently, applications of the Internet-based Networked Control System (INCS) become the main stream of researches. Due to the essential characteristics of data-transmission delay, INCS design has to consider the delay characteristics, especially in feedback control system design.
After comparing delay characteristics of TCP (Transmission Control Protocol), UDP (User Datagram Protocol), and recently proposed CSTP (Control System Transfer Protocol), this thesis proposes a new fuzzy flow control algorithm which is suitable for INCS data transmission. It is known that the network status varies according to the fluctuation of the data transmission depending on place and time. Based on the round trip time and the corresponding variation, the proposed algorithm adopts the genetic algorithm and fuzzy control method to adjust the packet's sending rate at sender, and thus the sender can real-time self-adjust the flow to improve the uniformity of transmission delay.
Finally, to verify the effectiveness of the proposed method, NS2 and Matlab software are integrated to build up the simulation platform. From the results of the simulation, it can be found that the proposed mechanism can reduce the transmission delay and improve the uniformity of delay. As a result, the stability and dynamical behavior of the closed-loop system are also improved.

並列關鍵字

Internet ； Flow control ； Genetic algorithm ； Internet-based Networked

參考文獻

[1] M. Mitsubishi, K. Kobayashi, T. Watanabe, H. Nakanishi, and B. Watanabe, “Development of an inter-word tele-micro-surgery system with operational environment information transmission capability,” Proceedings of IEEE International Conference on Robotics and Automation, vol. 3, 1995, pp. 3081-3088.

[3] Y. Wakita, S. Hirai, and K. Machida, “Intelligent monitoring system for limited communication path: telerobotic task execution over Internet,” Proceedings of IEEE/RSJ International Conference on Intelligent Robots and Systems, vol. 2, 1995, pp. 104-109.

[7] R. Oboe and P. Fiorini, “Internet-based telerobotics: problems and approaches,” Proceedings of the 8th International Conference on Advanced Robotics, 1997, pp. 765-770.

[8] R. Oboe and P. Fiorini, “A design and control environment for Internet-based telerobotics,” International Journal of Robotics Research, vol. 17, April 1998, pp. 433-449.

[10] S. Floyd and T. Henderson, “The new Reno modification to TCP’s fast recovery algorithm,” RFC 2582, April 1999.