李善強 彭秀艷 李強



關鍵詞:混沌系統;時變時滯;有限時間同步;自適應控制
DOI:10.15938/j.emc.2019.06.000
中圖分類號文獻標志碼:A 文章編號:1007 -449X(2019)06 -0000 -00
Abstract:In this paper, the issue of adaptive finitetime synchronization of multiple chaotic systems with timevarying delay is investigated. The chaotic systems with different structures and timevarying state delays are considered. Firstly, by designing appropriate adaptive update law, the gain of the controller can be updated online to achieve faster convergence speed. The design method of adaptive controller is presented. Then by using Lyapunov stability theorem and finitetime stability theory, it is proved that the designed adaptive controller and the corresponding control gain adaptive update law can guarantee the synchronization of states of multiple error dynamic systems in finite time, and the estimation of synchronization settling time is also given. Finally, the feasibility and effectiveness of the proposed adaptive finitetime synchronization control method is further validated by numerical simulation of three typical chaotic systems i.e. Lorenz system, Chen system and Lü system.
Keywords:chaotic systems; timevarying delay; finitetime synchronization; adaptive control
0 引 言
混沌系統同步問題具有廣闊的工程應用前景,例如物理、生物和信息科學以及混沌系統的同步在保密通信領域中起著重要作用[1-2]。因此,近年來混沌系統的同步控制問題得到研究者的廣泛關注。最初,研究者只是研究兩個混沌系統的同步控制問題,例如文獻[3]研究了兩個時變時滯混沌神經網絡的有限時間同步控制問題。隨后,具有時變時滯和有界擾動的混沌系統的有限時間同步控制已在文獻[4]中討論。文獻[5-6]研究了混沌系統的自適應有限時間同步問題。文獻[7]研究了兩個時滯混沌神經網絡的間歇同步控制問題。兩個不同的具有時變時滯混沌系統的投影同步在文獻[8]中被研究。利用脈沖控制方法,文獻[9]對混沌系統的延遲同步進行了分析。而文獻[10]針對帶有執行器故障的不確定混沌系統,研究了魯棒自適應容錯同步問題。對于兩個混沌系統的同步,相對簡單。而且,很多文獻都是假設兩個混沌系統的結構完全相同,在不同初始條件下,使得驅動系統和響應系統達到同步。
對于多個時滯混沌系統的同步控制研究變得越來越復雜,且面臨著更大的挑戰。文獻[11-14]研究了多個混沌系統同步控制問題,但是這些文獻均沒有考慮系統的時變時滯現象。因此,關于具有時變時滯的多個結構不同的混沌系統的有限時間同步控制是一個較復雜的研究問題,目前尚未見有關研究結果。
基于上述分析,本文研究了多個時滯混沌系統的有限時間同步控制問題。文章的主要貢獻如下:1)多個混沌系統具有不同的結構;2)給出了自適應控制器和自適應律的設計方法;3)引入投影比例因子,研究多個混沌系統的投影同步控制。適當地選擇投影因子,可知投影同步包括了通常的完全同步問題;4)給出了保證多個時滯混沌系統達到有限時間同步的充分條件。
4 結 論
研究了多個不同的具有時變時滯的混沌系統的有限時間投影同步問題。利用自適應控制的方法設計了有限時間同步自適應控制器。根據Lyapunov穩定性定理和有限時間穩定理論證明了所提自適應控制器可以保證多個的混沌系統有限時間投影同步。最后,通過算例仿真驗證了自適應控制器的可行性和有效性。
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(編輯:賈志超)