Research Article
Synchronization in Dynamically Coupled Fractional-Order
Chaotic Systems: Studying the Effects of Fractional Derivatives
J. L. Echenaus´ ıa-Monroy ,
1
C. A. Rodr´ ıguez-Mart´ ıne ,
1
L. J. Ontañ ´ on-Garc´ ıa ,
2
J. Alvarez,
1
and J. Pena Ramirez
1
1
Applied Physics Division, Center for Scientific Research and Higher Education at Ensenada, CICESE. Carr. Ensenada-Tijuana,
3918 Zona Playitas, Ensenada, 22860 BC, Mexico
2
Coordinaci´ on Acad´ emica Regi´ on Altiplano Oeste, Universidad Aut´ onoma de San Luis Potos´ ı,
Carretera a Santo Domingo 200, 78 600, Salinas de Hidalgo, S.L.P, Mexico
CorrespondenceshouldbeaddressedtoJ.L.Echenaus´ ıa-Monroy;jose.luis.echenausia@gmail.comandJ.PenaRamirez;
jpena@cicese.mx
Received 27 August 2021; Revised 23 October 2021; Accepted 4 December 2021; Published 24 December 2021
Academic Editor: Atila Bueno
Copyright © 2021 J. L. Echenaus´ ıa-Monroy et al. is is an open access article distributed under the Creative Commons
AttributionLicense,whichpermitsunrestricteduse,distribution,andreproductioninanymedium,providedtheoriginalworkis
properly cited.
is study presents the effectiveness of dynamic coupling as a synchronization strategy for fractional chaotic systems. Using an
auxiliary system as a link between the oscillators, we investigate the onset of synchronization in the coupled systems and we
analytically determine the regions where both systems achieve complete synchronization. In the analysis, the integration order is
considered as a key parameter affecting the onset of full synchronization, considering the stability conditions for fractional
systems. e local stability of the synchronous solution is studied using the linearized error dynamics. Moreover, some statistical
metrics such as the average synchronization error and Pearson’s correlation are used to numerically identify the synchronous
behavior. Two particular examples are considered, namely, the fractional-order R¨ ossler and Chua systems. By using bifurcation
diagrams,itisalsoshownthattheintegrationorderhasastronginfluencenotonlyontheonsetoffullsynchronizationbutalsoon
the individual dynamic behavior of the uncoupled systems.
1. Introduction
Synchronization is an emergent physical phenomenon
caused by the interaction of two or more dynamic entities
that pervade the natural world [1–4]. In the case of oscil-
lating units, the synchronization phenomenon can be de-
fined as the adjustment of temporal evolution to a common
rhythm.
Forthecaseofinteger-ordersystems,thereexistsavastand
mature literature where we can find different interconnection
schemes for synchronizing dynamic systems, like, for example,
master-slave synchronization scheme, adaptive synchroniza-
tion, and synchronization based on state observers, to name a
few [5–10]. Although each of these strategies is effective, there
are limitations in their applications, e.g., there are cases where
theseschemeshavemarginalrangesforwhichthesynchronous
response is achieved or have poor robustness to maintain a
stable synchronous state under the influence of external dis-
turbances. is is one of the reasons why dynamic intercon-
nections have emerged as an alternative to the classical static
schemes. In this case, the interaction between agents is indi-
rectly achieved through a suitably designed dynamic coupling
[11–13].istypeofsynchronizationstrategyhasshownbetter
performance than static couplings. In particular, dynamic
coupling increases the intervals of coupling strength values for
which it is possible to achieve synchronized behavior, and it
may also be possible to synchronize systems that cannot be
synchronized with static coupling [11].
Ontheotherhand,theuseoffractionalcalculushasbeen
extensively studied in nonlinear systems (see, e.g., [14–18])
and also, there exist notable contributions related to the
study of synchronization in fractional-order systems (see,
Hindawi
Complexity
Volume 2021, Article ID 7242253, 12 pages
https://doi.org/10.1155/2021/7242253