The Chen system is defined as follows8
d x ( t ) d t = a ( y ( t ) − x ( t ) ) {\displaystyle {\frac {dx(t)}{dt}}=a(y(t)-x(t))}
d y ( t ) d t = ( c − a ) x ( t ) − x ( t ) z ( t ) + c y ( t ) {\displaystyle {\frac {dy(t)}{dt}}=(c-a)x(t)-x(t)z(t)+cy(t)}
d z ( t ) d t = x ( t ) y ( t ) − b z ( t ) {\displaystyle {\frac {dz(t)}{dt}}=x(t)y(t)-bz(t)}
Plots of Chen attractor can be obtained with the Runge-Kutta method:9
parameters: a = 40, c = 28, b = 3
initial conditions: x(0) = -0.1, y(0) = 0.5, z(0) = -0.6
Multiscroll attractors also called n-scroll attractor include the Lu Chen attractor, the modified Chen chaotic attractor, PWL Duffing attractor, Rabinovich Fabrikant attractor, modified Chua chaotic attractor, that is, multiple scrolls in a single attractor.10
An extended Chen system with multiscroll was proposed by Jinhu Lu (吕金虎) and Guanrong Chen11
Lu Chen system equation
d y ( t ) d t = x ( t ) − x ( t ) z ( t ) + c y ( t ) + u {\displaystyle {\frac {dy(t)}{dt}}=x(t)-x(t)z(t)+cy(t)+u}
parameters:a = 36, c = 20, b = 3, u = -15.15
initial conditions:x(0) = .1, y(0) = .3, z(0) = -.6
System equations:12
d x ( t ) d t = a ( y ( t ) − x ( t ) ) , {\displaystyle {\frac {dx(t)}{dt}}=a(y(t)-x(t)),}
d y ( t ) d t = ( c − a ) x ( t ) − x ( t ) f + c y ( t ) , {\displaystyle {\frac {dy(t)}{dt}}=(c-a)x(t)-x(t)f+cy(t),}
In which
f = d 0 z ( t ) + d 1 z ( t − τ ) − d 2 sin ( z ( t − τ ) ) {\displaystyle f=d0z(t)+d1z(t-\tau )-d2\sin(z(t-\tau ))}
params := a = 35, c = 28, b = 3, d0 = 1, d1 = 1, d2 = -20..20, tau = .2
initv := x(0) = 1, y(0) = 1, z(0) = 14
In 2001, Tang et al. proposed a modified Chua chaotic system13
d x ( t ) d t = α ( y ( t ) − h ) {\displaystyle {\frac {dx(t)}{dt}}=\alpha (y(t)-h)}
d y ( t ) d t = x ( t ) − y ( t ) + z ( t ) {\displaystyle {\frac {dy(t)}{dt}}=x(t)-y(t)+z(t)}
d z ( t ) d t = − β y ( t ) {\displaystyle {\frac {dz(t)}{dt}}=-\beta y(t)}
h := − b sin ( π x ( t ) 2 a + d ) {\displaystyle h:=-b\sin \left({\frac {\pi x(t)}{2a}}+d\right)}
params := alpha = 10.82, beta = 14.286, a = 1.3, b = .11, c = 7, d = 0
initv := x(0) = 1, y(0) = 1, z(0) = 0
Aziz Alaoui investigated PWL Duffing equation in 2000:14
PWL Duffing system:
d x ( t ) d t = y ( t ) {\displaystyle {\frac {dx(t)}{dt}}=y(t)}
d y ( t ) d t = − m 1 x ( t ) − ( 1 / 2 ( m 0 − m 1 ) ) ( | x ( t ) + 1 | − | x ( t ) − 1 | ) − e y ( t ) + γ cos ( ω t ) {\displaystyle {\frac {dy(t)}{dt}}=-m_{1}x(t)-(1/2(m_{0}-m_{1}))(|x(t)+1|-|x(t)-1|)-ey(t)+\gamma \cos(\omega t)}
params := e = .25, gamma = .14+(1/20)i, m0 = -0.845e-1, m1 = .66, omega = 1; c := (.14+(1/20)i),i=-25...25;
initv := x(0) = 0, y(0) = 0;
Miranda & Stone proposed a modified Lorenz system:15
d x ( t ) d t = 1 / 3 ∗ ( − ( a + 1 ) x ( t ) + a − c + z ( t ) y ( t ) ) + ( ( 1 − a ) ( x ( t ) 2 − y ( t ) 2 ) + ( 2 ( a + c − z ( t ) ) ) x ( t ) y ( t ) ) {\displaystyle {\frac {dx(t)}{dt}}=1/3*(-(a+1)x(t)+a-c+z(t)y(t))+((1-a)(x(t)^{2}-y(t)^{2})+(2(a+c-z(t)))x(t)y(t))} 1 3 x ( t ) 2 + y ( t ) 2 {\displaystyle {\frac {1}{3{\sqrt {x(t)^{2}+y(t)^{2}}}}}}
d y ( t ) d t = 1 / 3 ( ( c − a − z ( t ) ) x ( t ) − ( a + 1 ) y ( t ) ) + ( ( 2 ( a − 1 ) ) x ( t ) y ( t ) + ( a + c − z ( t ) ) ( x ( t ) 2 − y ( t ) 2 ) ) {\displaystyle {\frac {dy(t)}{dt}}=1/3((c-a-z(t))x(t)-(a+1)y(t))+((2(a-1))x(t)y(t)+(a+c-z(t))(x(t)^{2}-y(t)^{2}))} 1 3 x ( t ) 2 + y ( t ) 2 {\displaystyle {\frac {1}{3{\sqrt {x(t)^{2}+y(t)^{2}}}}}}
d z ( t ) d t = 1 / 2 ( 3 x ( t ) 2 y ( t ) − y ( t ) 3 ) − b z ( t ) {\displaystyle {\frac {dz(t)}{dt}}=1/2(3x(t)^{2}y(t)-y(t)^{3})-bz(t)}
parameters: a = 10, b = 8/3, c = 137/5;
initial conditions: x(0) = -8, y(0) = 4, z(0) = 10
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阎振亚著 《复杂非线性波的构造性理论及其应用》第17页 SCIENCEP 2007年 ↩
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Chen, Guanrong; Jinhu Lu (2006). "Generating Multiscroll Chaotic Attractors: Theories, Methods and Applications" (PDF). International Journal of Bifurcation and Chaos. 16 (4): 793–794. Bibcode:2006IJBC...16..775L. CiteSeerX 10.1.1.927.4478. doi:10.1142/s0218127406015179. Retrieved 2012-02-16. http://www.ee.cityu.edu.hk/~gchen/pdf/LC-IJBC06-survey.pdf ↩
J. Lu, G. Chen p. 837 ↩
J.Liu and G Chen p834 ↩