Abstract
Synchronization phenomena have been studied from a control point of view for many years. However, the vast majority of papers consider complete synchronization, and very few have been devoted to phase synchronization. This paper addresses control and observability aspects of phase synchronization. In order to focus on fundamental aspects, a feedback control framework related to master–slave synchronization is considered. Comparing results using Cartesian and cylindrical coordinates in the context of such a framework and with three known oscillator models, it is argued that (1) observability does not play a significant role in phase synchronization, although it is granted that it might be relevant for complete synchronization, and (2) a practical difficulty is faced when phase synchronization is aimed at, but the control action is not a direct function of the phase error, as it is usually the case in synchronization studies. This difficulty with its fundamental and practical consequences is investigated in some detail.
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Notes
In case of bidirectional coupling (not directly investigated in this paper), the term \(k_2[x_1(t)-x_2(t)]\) would be added to the first equation of the second oscillator, and the oscillators are no longer called master or slave.
Ideally, this signal should be a function of the phase error, e.g., \(e(t)=\phi _2(t)-\phi _1(t)\).
A common nonlinear and \(2\pi \)-periodic control action is \(m_\phi (t)=k_\phi \sin [r_\phi (t)-\phi _1(t)]\). In this paper we use a \(2\pi \)-periodic control action \(m_\phi (t)=k_\phi \mathtt{wraptopi} [r_\phi (t)-\phi _1(t)]\), where wraptopi wraps angles to the range \((-\pi ,\,\pi ]\).
In 2D this boils down to polar coordinates. Because in this paper 2D and 3D oscillators are considered, the term cylindrical coordinates will be used.
The arctangent function is considered with two arguments: atan2(\(y,\,x\)), where the angle information can be obtained in the four quadrants.
As for the origin of this system the following quotation is relevant “Since the first description of two-dimensional radially symmetric differential equations with limit cycles was given by Poincaré, we propose that these systems be called Poincaré oscillators” [31, p. 25]. However, it is pointed out that the denomination is used for a class of two-dimensional differential equations and the specific oscillator in (8) is not considered in that reference.
Abbreviations
- CA:
-
Control action
- CS:
-
Complete synchronization
- MV:
-
Manipulated variable
- PS:
-
Phase synchronization
References
Boccaletti, S., Kurths, J., Osipov, G., Valladares, D.L., Zhou, C.S.: The synchronization of chaotic systems. Phys. Rep. 366(1–2), 1–101 (2002)
Osipov, G.V., Kurths, J., Zhou, C.: Synchronization in Oscillatory Networks. Springer, Berlin (2007)
Fujisaka, H., Yamada, T.: Stability theory of synchronized motion in coupled-oscillator systems. Prog. Theor. Phys. 69(1), 32–47 (1983). https://doi.org/10.1143/PTP.69.32
Kapitaniak, T.: Synchronization of chaos using continuous control. Phys. Rev. E 50(2), 1642–1644 (1994)
Rosenblum, M.G., Pikovsky, A.S., Kurths, J.: Phase synchronization of chaotic oscillators. Phys. Rev. Lett. 76(11), 1804–1807 (1996)
Piqueira, J.R.C.: Network of phase-locking oscillators and a possible model for neural synchronization. Commun. Nonlinear Sci. Numer. Simul. 16(9), 3844–3854 (2011). https://doi.org/10.1016/j.cnsns.2010.12.031
Kurths, J., Romano, M.C., Thiel, M., Osipov, G.V., Ivanchenko, M.V., Kiss, I.Z., Hudson, J.L.: Synchronization analysis of coupled noncoherent oscillators. Nonlinear Dyn. 44, 135–149 (2006). https://doi.org/10.1007/s11071-006-1957-x
Pereira, T., Batista, M.S., Kurths, J.: General framework for phase synchronization through localized sets. Phys. Rev. E 75, 026216 (2007). https://doi.org/10.1103/PhysRevE.75.026216
Belykh, V.N., Osipov, G.V., Kuckländer, N., Blasius, B., Kurths, J.: Automatic control of phase synchronization in coupled complex oscillators. Physica D 200(1–2), 81–104 (2005). https://doi.org/10.1016/j.physd.2004.10.008
Letellier, C., Aguirre, L.A.: Interplay between synchronization, observability, and dynamics. Phys. Rev. E 82, 016204 (2010). https://doi.org/10.1103/PhysRevE.82.016204
Aguirre, L.A., Letellier, C.: Controllability and synchronizability: are they related? Chaos Solitons Fractals 83, 242–251 (2016). https://doi.org/10.1016/j.chaos.2015.12.009
Sendiña-Nadal, I., Boccaletti, S., Letellier, C.: Observability coefficients for predicting the class of synchronizability from the algebraic structure of the local oscillators. Phys Rev E 94, 042205 (2016). https://doi.org/10.1103/PhysRevE.94.042205
Parlitz, U., Junge, L., Kocarev, L.: Synchronization-based parameter estimation from time series. Phys. Rev. E 54(6), 6253–6259 (1996). https://doi.org/10.1103/PhysRevE.54.6253
Maybhate, A., Amritkar, R.E.: Use of synchronization and adaptive control in parameter estimation from a time series. Phys. Rev. E 59, 284–293 (1999). https://doi.org/10.1103/PhysRevE.59.284
Freitas, U.S., Macau, E.E.N., Grebogi, C.: Using geometric control and chaotic synchronization to estimate an unknown model parameter. Phys. Rev. E 71(4), 047203 (2005). https://doi.org/10.1103/PhysRevE.71.047203
Sedigh-Sarvestani, M., Schiff, S.J., Gluckman, B.J.: Reconstructing mammalian sleep dynamics with data assimilation. PLoS Comput. Biol. 8(11), e1002788 (2012). https://doi.org/10.1371/journal.pcbi.1002788
Buscarino, A., Frasca, M., Branciforte, M., Fortuna, L., Sprott, J.C.: Synchronization of two Rössler systems with switching coupling. Nonlinear Dyn. 88, 673–683 (2016). https://doi.org/10.1007/s11071-016-3269-0
Mahmoud, G.M., Mahmoud, E.E.: Phase and antiphase synchronization of two identical hyperchaotic complex nonlinear systems. Nonlinear Dyn. 61, 141–152 (2010). https://doi.org/10.1007/s11071-009-9637-2
Das, S., Srivastava, M., Leung, A.Y.T.: Hybrid phase synchronization between identical and nonidentical three-dimensional chaotic systems using the active control method. Nonlinear Dyn. 73, 2261–2272 (2013). https://doi.org/10.1007/s11071-013-0939-z
Stone, E.F.: Frequency entrainment of a phase coherent attractor. Phys. Lett. A 163, 367–374 (1992)
Kuramoto, Y.: Self-entrainment of a population of coupled non-linear oscillators. In: Araki, H. (ed.) Lecture Notes in Physics, vol. 39, pp. 420–422. Springer, Berlin (1975)
Dörfler, F., Bullo, F.: Synchronization in complex networks of phase oscillators: a survey. Automatica 50, 1539–1564 (2014)
Josić, K., Mar, D.J.: Phase synchronization of chaotic systems with small phase diffusion. Phys. Rev. E 64, 056234 (2001). https://doi.org/10.1103/PhysRevE.64.056234
Hsieh, G.C., Hung, J.C.: Phase-locked loop techniques—a survey. IEEE Trans. Industr. Electron. 43(6), 609–615 (1996)
Kalman, R.E.: On the general theory of control systems. In: Proceedings of the First IFAC Congress Automatic Control, Butterworths, London, pp. 481–492 (1960)
Hermann, R., Krener, A.J.: Nonlinear controllability and observability. IEEE Trans. Autom. Control 22(5), 728–740 (1977)
Parlitz, U., Schumann-Bischoff, J., Luther, S.: Local observability of state variables and parameters in nonlinear modeling quantified by delay reconstruction. Chaos 24, 024411 (2014). https://doi.org/10.1063/1.4884344
Letellier, C., Aguirre, L.A., Maquet, J.: Relation between observability and differential embeddings for nonlinear dynamics. Phys. Rev. E 71, 066213 (2005)
Pecora, L.M., Carroll, T.L.: Synchronization in chaotic systems. Phys. Rev. Lett. 64(8), 821–824 (1990)
Rosenblum, M., Pikovsky, A.S., Kurths, J.: From phase to lag synchronization in coupled chaotic oscillators. Phys. Rev. Lett. 78(22), 4193–4196 (1997)
Glass, L., Mackey, M.C.: From Clocks to Chaos: The Rhythms of Life. Princeton University Press, Princeton (1988)
van der Pol, B.: Forced oscillations in a circuit with non-linear resistance. Philos. Mag. J. Sci. 3(13), 65–80 (1927). https://doi.org/10.1080/14786440108564176
Rössler, O.E.: An equation for continuous chaos. Phys. Lett. 57A(5), 397–398 (1976)
Mormann, F., Lehnertz, K., David, P., Elger, C.E.: Mean phase coherence as a measure for phase synchronization and its application to the EEG of epilepsy patients. Physica D 144, 358–369 (2000)
Acknowledgements
LAA gratefully acknowledges the financial support from CNPq. LF is grateful to IFMG Campus Betim for an academic leave. The authors thank Christophe Letellier for commenting on an early draft of this paper.
Funding
Funding was provided by Conselho Nacional de Desenvolvimento Científico e Tecnológico (Grant No. 302079/2011-4).
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Aguirre, L.A., Freitas, L. Control and observability aspects of phase synchronization. Nonlinear Dyn 91, 2203–2217 (2018). https://doi.org/10.1007/s11071-017-4009-9
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DOI: https://doi.org/10.1007/s11071-017-4009-9