Quasi-periodic Flows in Time-Delay Systems

In this chapter, from Luo (2014 ), period-m flows to quasi-periodic flows in time-delayed nonlinear dynamical systems will be presented. The analytical solutions of quasi-periodic flows in autonomous time-delayed systems will be discussed, and the analyti

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Quasi-periodic Flows in Time-Delay Systems

In this chapter, from Luo (2014), period-m flows to quasi-periodic flows in time-delayed nonlinear dynamical systems will be presented. The analytical solutions of quasi-periodic flows in autonomous time-delayed systems will be discussed, and the analytical solutions of quasi-periodic flows in periodically forced, time-delayed nonlinear dynamical systems will be presented. The analytical solutions of quasi-periodic solutions in free and periodically forced, time-delayed vibration systems will be presented.

4.1

Time-Delay Nonlinear Systems

Consider quasi-periodic flows in autonomous, time-delayed nonlinear systems, and the analytical solution of quasi-periodic flows relative to period-m flow is given as follows. Theorem 4.1 Consider a nonlinear, time-delayed, dynamical system as x_ ¼ Fðx; xs ; pÞ 2 Rn

ð4:1Þ

where Fðx; xs ; pÞ is a C r -continuous nonlinear vector function (r  1). (A) If such a time-delayed dynamical system has a period-m flow xðmÞ ðtÞ with finite norm jjxðmÞ jj and period T ¼ 2p=X, there is a generalized coordinate transformation for the period-m flow of Eq. (4.1) in the form of ðmÞ

xðmÞ ðtÞ ¼ a0 ðtÞ þ sðmÞ

xsðmÞ ðtÞ ¼ a0

ðtÞ þ

1 X

k k bk=m ðtÞ cosð hÞ þ ck=m ðtÞ sinð hÞ; m m k¼1 1 X

k k bsk=m ðtÞ cos½ ðh  hs Þ þ csk=m ðtÞ sin½ ðh  hs Þ m m k¼1

© Springer International Publishing Switzerland 2017 A.C.J. Luo, Periodic Flows to Chaos in Time-delay Systems, Nonlinear Systems and Complexity 16, DOI 10.1007/978-3-319-42664-8_4

ð4:2Þ

115

116

4 Quasi-periodic Flows in Time-Delay Systems sðmÞ

with a0

ðmÞ

sðmÞ

ðmÞ

¼ a0 ðt  sÞ; bk ð0Þ

ðmÞ

sðmÞ

¼ bk ðt  sÞ; ck ðmÞ

ðmÞ

ðmÞ

¼ ck ðt  sÞ; hs ¼ Xs and

ðmÞ

¼ ða01 ; a02 ;    ; a0n ÞT ;

a1  a0 ðkÞ

a2  bk=m ¼ ðbk=m1 ; bk=m2 ;    ; bk=mn ÞT ; ðkÞ

a3  ck=m ¼ ðck=m1 ; ck=m2 ;    ; ck=mn ÞT sð0Þ

 a0

sðmÞ

sðkÞ

 bsk=m ¼ ðbsk=m1 ; bsk=m2 ;    ; bsk=mn ÞT ;

sðkÞ

 csk=m ¼ ðcsk=m1 ; csk=m2 ;    ; csk=mn ÞT

a1 a2 a3

sðmÞ

sðmÞ

sðmÞ

¼ ða01 ; a02 ;    ; a0n ÞT ;

ð4:3Þ

which, under jjxðmÞ ðtÞ  xðmÞ ðtÞjj\e and jjxsðmÞ ðtÞ  xsðmÞ ðtÞjj\es with prescribed small e [ 0 and es [ 0, can be approximated by a finite term transformation xðmÞ ðtÞ as ðmÞ

xðmÞ ðtÞ ¼ a0 ðtÞ þ sðmÞ

xsðmÞ ðtÞ ¼ a0

ðtÞ þ

N0 X

k k bk=m ðtÞ cosð hÞ þ ck=m ðtÞ sinð hÞ; m m k¼1 N0 X

ð4:4Þ

k k bsk=m ðtÞ cos½ ðh  hs Þ þ csk=m ðtÞ sin½ ðh  hs Þ m m k¼1

and the generalized coordinates are determined by a_ ¼ f s0 ða; as ; pÞ

ð4:5Þ

where k0 ¼ diagðInn ; 2Inn ;    ; NInn Þ; ð0Þ

ðmÞ

ðkÞ

ðkÞ

a1  a0 ; a2  bk=m ; a3  ck=m ; sð0Þ

a1

sðmÞ

 a0

sðkÞ

; a2

ðkÞ

 bsk=m ; a3  csk=m

ð0Þ

a1 ¼ a1 ; ð1Þ

ð2Þ

ðNÞ

ð1Þ

ð2Þ

ðNÞ

a2 ¼ ða2 ; a2 ;    ; a2 ÞT  bðmÞ ; a3 ¼ ða3 ; a3 ;    ; a3 ÞT  cðmÞ ; sð0Þ

as1 ¼ a1 ; sð1Þ

sð2Þ

sðNÞ T

sð1Þ

sð2Þ

sðNÞ T

ðmÞ

ðmÞ

as2 ¼ ða2 ; a2 ;    ; a2 as3 ¼ ða3 ; a3 ;    ; a3

Þ  bsðmÞ ; Þ  csðmÞ ;

ðmÞ

F1 ¼ F0

ðmÞ

F2 ¼ ðF11 ; F12 ;    ; F1N ÞT ;

4.1 Time-Delay Nonlinear Systems

117 ðmÞ

ðmÞ

ðmÞ

F3 ¼ ðF21 ; F22 ;