A Memristor-based Chaotic System with Bifurcation Analysis
Xiaofang Hu, Gang Feng
Dept. Mechanical and Biomedical
Engineering
City University of Hong Kong
Hong Kong, China
E-mail: xiaofanghs@gmail.com,
megfeng@cityu.edu.hk
Shukai Duan, Weihong Yin
College of Electronics and
Information Engineering
Southwest University
Chongqing, China
Email: duansk@swu.edu.cn
weihong8596@gmail.com
Guanrong Chen
Dept. Electronic Engineering
City University of Hong Kong
Hong Kong, China
E-mail: eegchen@Cityu.edu.hk
Abstract—This paper proposes and investigates a memristor-
based chaotic system by incorporating an HP TiO
2
memristor
into the canonical Chen’s chaotic system. More precisely, a
charge-controlled memristor model with some appropriate
boundary conditions is introduced. The relationship between
the electric charge and the flux passing through the memristor
is formulated and then employed as a nonlinear term in the
constructed chaotic system. The rich dynamical behaviors of
the memristor-based system are demonstrated by calculating
the Lyapunov exponent spectrum and Lyapunov dimension,
observing the chaotic attractors, analyzing the bifurcations.
Keywords-memristors; chaos; Lyapunov exponent; chaotic
attractor; bifurcation analysis
I. INTRODUCTION
In 1971, memristor was predicted by Leon Chua [1],
which identified the link between flux and charge of a
missing electric element. About 40 years later, physical
memristors were developed by William and his team from
the Hewlett-Packard (HP) Lab, in 2008 [2]. The memristor
has received considerable attention thereafter, from both
academic and industrial communities, to the research on its
theoretical models [3-4], hardware implementations [5], and
potential applications [5-6].
Memristor has several variants today. They are two-port
nonlinear nanoscale electric devices, featuring a pinched
hysteresis current-voltage loop under periodic excitation.
However, the I-V loop alone could not uniquely define a
memristor but the constructive relationships can represent a
memristor device. One of the constructive relationships is
constructed by the flux (time accumulation of the voltage)
and the charge (time accumulation of the current). At
present, memristors have found many promising potentials in
widespread applications [7-11]. Particularly, due to the
properties of continuously variable resistance and zero-
power message storage, memristor is considered as a
competitive candidate for developing the next-generation
non-volatile memory [7]. In addition, memristors have
variable conductance states depending on the historical
record of external excitation, which exhibits a striking
resemblance to a biological synapse. Therefore, memristors
have become an ideal hardware component for artificial
synaptic circuit, which opens a new venue for implementing
powerful neuromorphic computing architectures [8]. In
nonlinear circuits, memristors also bring many opportunities.
In particular, novel implementations of chaotic oscillators
consisting of memristive elements have built up a new
paradigm for research and potential applications [9-11].
Theoretical research and physical realizations of varieties
in chaos generators have experienced a swift progress and
development in the past three decades [11-12]. However, the
practical applications of chaos have not been fully explored
because of technical difficulties in implementing chaos
generators by traditional means. Memristors, with nanoscale
size and prominent nonlinear characteristics, are likely to
further promote this traditional research buy a new means.
Noticeably, by replacing Chua’s diode with a more general
memristor, or memristive system, several Chua-circuit-based
chaotic oscillators could be constructed [9-10]. Subsequently,
many research efforts have been devoted to this promising
subject, including design, implementations and dynamics
analysis of various memristor-based chaotic systems [11, 14,
15].
This paper proposes and studies a novel chaotic system
by introducing an HP memristor into the canonical Chen’s
oscillator. Firstly, the theoretical charge-controlled model
and the constructive charge-flux relationship in memristor
are introduced in Section II. Then, the new memristor-based
chaotic system is proposed in Section III, with a systematic
analysis of its dynamical behaviors. To that end, a further
investigation into various chaotic attractors and bifurcations
are carried out in Section IV. Finally, brief conclusions are
drawn in Section V.
II. T
HE HP MEMRISTOR MODEL
A memristor is theoretically defined via the flux-charge
constitutive relationship by
()ddqdq
dt dq dt
ϕϕ
=⋅
, (1)
which leads to the relationship between the voltage across
and the current passing through the memristor, as follows:
()
() () ( ) ()
dq
it vt W vt
d
ϕ
ϕ
ϕ
==
, (2a)
()
() () ( )()
dq
vt it M qit
dq
ϕ
==
, (2b)
2014 Sixth International Conference on Computational Intelligence and Communication Networks
978-1-4799-6929-6/14 $31.00 © 2014 IEEE
DOI 10.1109/.81
329
2014 Sixth International Conference on Computational Intelligence and Communication Networks
978-1-4799-6929-6/14 $31.00 © 2014 IEEE
DOI 10.1109/CICN.2014.81
329