灰色比例積分控制器應用於高精度時間同步協定

Using Grey Proportional Integral Controller for Precision Time Synchronization Protocol

李炳輝(Ping-Hui Lee)

指導教授 ： 張帆人

共同指導教授 ： 涂昆源(Kun-Yuan Tu)

國立臺灣大學/電機資訊學院/電機工程學研究所/碩士(2008年)

https://doi.org/10.6342/NTU.2008.03161

摘要

IEEE1588標準係一高精度時間同步協定(PTP)，其主要設計用於分散式聯網系統各節點之即時時間同步。在子網中，PTP系統預期可達次微秒(<10-6秒)時間同步性能。因此，PTP系統可應用於傳統量測與控制系統、工業自動化、通訊系統、電力系統及眾多現代技術領域。時間伺服器(Clock servo)在PTP系統中扮演重要的角色。通常時間伺服器是利用比例積分(PI)控制器來實現。主時鐘(Master clock)及從時鐘(Slave clock)之時間偏差則回授至PI控制器，參考PI控制器之輸出，可調整從時鐘同步於主時鐘，且相對計時速率(Relative tick-rate)因此可趨於穩定。為增進PI控制器之性能，本研究採用灰色理論求得PI控制器中比例項之參數。從時鐘相對於主時鐘之時間偏移(Drift)，可由灰色預測演算法求得。因此，灰色PI控制器可縮短暫態響應時間，使系統更快趨於穩定。為了評估系統性能，本研究結合了PTP軟體及網路介面，建立一個子網路系統。且本論文採用ITU-T推薦之亞倫方差進行系統穩定度分析。結果顯示，灰色PI控制器性能優於傳統PI控制器，引用灰色PI控制器，可大幅縮短系統暫態響應時間。

關鍵字

高精度時間同步協定 ； 時間同步協定 ； 灰色 ； 比例積分器

並列摘要

IEEE1588 standard is a precision time synchronization protocol (PTP). It is designed to synchronize real-time clocks in the nodes of a distributed system that communicate using a network. Within a subnet, the PTP system is expected to achieve the synchronization accuracy in sub-microsecond range. Thus, it is applicable to traditional measurement and control systems, industrial automation systems, communication systems, electrical power systems and many other areas of modern technology.The unit of clock servo plays important roles in the PTP system. It is usually implemented by proportional integral (PI) controller. The time offsets between the master and the slave clock are fed into the PI controller. The output of the PI controller is used to steer the slave clock to synchronize with the master clock. Therefore, the relative tick-rate of the slave clock can be stabilized. In order to improve the performance of the PI controller, this study adopts the gray theory to determine the parameter of the proportional term of the PI controller. The drift of the time offset from master clock can be obtained by using the gray prediction algorithm. Accordingly, the gray PI controller makes the system reduce the time to reach steady state. To assess the performance of the system, this study integrates the PTP software and the network interface with timestamper to establish a subnet. For the stability analysis of the system under tests, this paper utilizes the ITU-T recommended Allan deviation. Experimental results show that the performance of the gray PI controller is better than the traditional one. The transient response time of the system is significantly reduced by introducing the proposed gray PI controller.

並列關鍵字

IEEE 1588 ； Grey ； ptp

參考文獻

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