Various active vibration suppression techniques, which use feedback control, are implemented on the structures. In real application, time delay can not be avoided especially in the feedback line of the actively controlled systems. The effects of the delay have to be thoroughly understood from the perspective of system stability and the performance of the controlled system. Often used control laws are developed without taking the delay into account. They fulfill the design requirements when free of delay. As unavoidable delay appears, however, the performance of the control changes. This work addresses the stability analysis of such dynamics as the control law remains unchanged but carries the effect of feedback time-delay, which can be varied. For this stability analysis along the delay axis, we follow up a recent methodology of the authors, the Direct Method (DM), which offers a unique and unprecedented treatment of a general class of linear time invariant time delayed systems (LTI-TDS). We discuss the underlying features and the highlights of the method briefly. Over an example vibration suppression setting we declare the stability intervals of the dynamics in time delay space using the DM. Having assessed the stability, we then look at the frequency response characteristics of the system as performance indications.

1.
Olgac, N., 1995, “Delayed Resonators as Active Dynamic Absorbers,” United States Patent 5,431,261.
2.
Olgac, N., Special Lecture at the 3rd IFAC Workshop on TDS 2001, http://www.siue.edu/ifacdelay/
3.
Seto, K., and Furuishi, Y., 1991, “A Study on Active Dynamic Absorber,” ASME Proceedings, Paper DE, Vol. 38, pp. 263–270.
4.
Seto
,
K.
, and
Yamashita
,
S.
,
1991
, “
Simultaneous Optimum Design Method for Multiple Dynamic Absorbers to Control Multiple Resonance Peaks
,”
SAE Transactions
,
100
, pp.
1481
1489
.
5.
Olgac
,
N.
, and
Hosek
,
M.
,
1998
, “
A New Perspective and Analysis for Regenerative Machine Tool Chatter
,”
Int. J. Mach. Tools Manuf.
,
38
(
7
), pp.
783
798
.
6.
Tlusty, J, 1985, “Machine Dynamics,” R. I. King, ed., Handbook of High Speed Machining Technology, Chapman and Hall, New York.
7.
Olgac
,
N.
, and
Holm-Hansen
,
B.
,
1994
, “
A Novel Active Vibration Absorption Technique: Delayed Resonator
,”
J. Sound Vib.
,
176
, pp.
93
104
.
8.
Olgac
,
N.
,
Elmali
,
H.
,
Hosek
,
M.
, and
Renzulli
,
M.
,
1997
, “
Active Vibration Control of Disturbed Systems Using Delayed Resonator with Acceleration Feedback
,”
ASME J. Dyn. Syst., Meas., Control
,
119
, pp.
380
388
.
9.
Chen
,
J.
,
Gu
,
G.
, and
Nett
,
C. N.
,
1994
, “
A New Method for Computing Delay Margins for Stability of Linear Delay Systems
,”
Syst. Control Lett.
,
26
, pp.
107
117
.
10.
Chen
,
J.
,
1995
, “
On Computing the Maximal Delay Intervals for Stability of Linear Delay Systems
,”
IEEE Trans. Autom. Control
,
40
(
6
), pp.
1087
1092
.
11.
Hale
,
J. K.
, and
Verduyn Lunel
,
S. M.
,
2001
, “
Effects of Small Delays on Stability and Control
,”
Operator Theory; Advances and Applications
,
122
, pp.
275
301
.
12.
Hale
,
J. K.
, and
Verduyn Lunel
,
S. M.
,
2001
, “
Strong Stabilization of Neutral Functional Differential Equations
,”
IMA J. Math. Control Inform.
,
19
, pp.
1
19
.
13.
Hale, J. K., and Verduyn Lunel, S. M., 1993, Introduction to Functional Differential Equations, Springer-Verlag.
14.
Hale
,
J. K.
,
Infante
,
E. F.
, and
Tsen
,
F.-S. P.
,
1985
, “
Stability in Linear Delay Equations
,”
J. Math. Anal. Appl.
,
105
, pp.
533
555
.
15.
Hertz
,
D.
,
Jury
,
E. I.
, and
Zeheb
,
E.
,
1984
, “
Simplified Analytic Stability Test for Systems with Commensurate Time Delays
,”
IEE Proc.
,
131
(
1
), Pt(D), pp.
52
56
.
16.
Jalili
,
N.
, and
Olgac
,
N.
,
1999
, “
Multiple Delayed Resonator Vibration Absorber for MDOF Mechanical Structures
,”
J. Sound Vib.
,
223
(
4
), pp.
567
585
.
17.
Kolmanovski, V. B., and Nosov, V. R., 1986, Stability of Functional Differential Equations, Academic Press, London, Great Britain.
18.
Niculescu, S-I., 2001, Delay Effects on Stability, Springer-Verlag.
19.
Zhang
,
J.
,
Knospe
,
C. R.
, and
Tsiotras
,
P.
,
2001
, “
Stability of Time-delay Systems: Equivalence Between Lyapunov and Scaled Small-gain Conditions
,”
IEEE Trans. Autom. Control
,
46
(
3
), pp.
482
486
.
20.
Gu
,
K.
, and
Niculescu
,
S.-I.
,
2000
, “
Additional Dynamics in Transformed Time-Delay Systems
,”
IEEE Trans. Autom. Control
,
45
(
3
), pp.
572
575
.
21.
Park
,
P.
,
1999
, “
A Delay-Dependent Stability Criterion for Systems with Uncertain Time-Invariant Delays
,”
IEEE Trans. Autom. Control
,
44
, pp.
876
877
.
22.
Olgac
,
N.
, and
Sipahi
,
R.
,
2002
, “
An Exact Method for the Stability Analysis of Time Delayed LTI Systems
,”
IEEE Trans. Autom. Control
,
47
(
5
), pp.
793
797
.
23.
Cooke
,
K. L.
, and
van den Driessche
,
P.
,
1986
, “
On Zeroes of Some Transcendental Equations
,”
Funkcialaj Ekvacioj
,
29
, pp.
77
90
.
24.
Thowsen
,
A.
,
1981
, “
The Routh-Hurwitz Method for Stability Determination of Linear Differential-Difference Systems
,”
Int. J. Control
,
33
(
5
), pp.
991
995
.
25.
Thowsen
,
A.
,
1981
, “
An Analytic Stability Test for a Class of Time-Delay Systems
,”
IEEE Trans. Autom. Control
,
26
(
3
), pp.
735
736
.
26.
Thowsen
,
A.
,
1982
, “
Delay-independent Asymptotic Stability of Linear Systems
,”
IEE Proc.
,
29
, pp.
73
75
.
27.
Seto, K., 1995, “Structural Modeling and Vibration Control.” Internal Report, Nihon University. Department of Mechanical Engineering, College of Science and Technology, Nihon University, 1-8-14 Kanda Surugadai Chiyoda-ku, Tokyo, 101-8308, Japan.
You do not currently have access to this content.