For a six degree-of-freedom active vibration isolation system, a control strategy based on modal decoupling is proposed. This has the advantage of controlling the modal directions on a centralized single-input single-output basis. As a consequence, stability and performance can be imposed in each of the modal directions separately. An experimental demonstration is given using a dummy metrology frame. That is, a 1600 kg payload mass supported by three combined pneumatic and Lorentz controlled isolators. With this setup, two unstable modal directions resulting from a high center of gravity are stabilized without compromising performance in any of the remaining directions. In fact, performance in the remaining directions is enhanced using manual loop shaping.

1.
Rivin
E.I.
,
2003
, Passive Vibration Isolation, ASME Press, New York.
2.
Yasuda
M.
,
Osaka
T.
, and
Ikeda
M.
,
1996
, “
Feedforward Control of a Vibration Isolation System for Disturbance Suppression
,” Proc. 35th Conference on Decision and Control, Kobe, Japan, pp.
1229
1233
.
3.
Yoshioka
H.
,
Takahashi
Y.
,
Katayama
K.
,
Imazawa
T.
, and
Murai
N.
,
2001
, “
An Active Microvibration Isolation System for Hi-tech Manufacturing Facilities
,”
J. Vibr. Acoust.
,
123
, pp.
269
275
.
4.
Elliott
S.
,
Serrand
M.
, and
Gardonio
P.
,
2001
, “
Feedback Stability Limits for Active Isolation Systems with Reactive and Inertial Actuators
,”
J. Vibr. Acoust.
,
123
, pp.
250
261
.
5.
Miura
T.
,
Ikeda
M.
, and
Yasuda
M.
,
2000
, “
Robust Position and Attitude Control of an Active Vibration Isolation System
,” Proc. MOVIC, Sydney, Australia,
2
, pp.
469
474
.
6.
Zhang
Y
, and
Alleyne
A.
,
2003
, “
A Simple Novel Approach to Active Vibration Isolation With Electorhydraulic Actuation
,”
ASME J. Dyn. Syst., Meas., Control
,
125
, pp.
125
128
.
7.
Kim
S-M
,
Elliott
S.
, and
Brennan
M. J.
,
2001
, “
Decentralized Control for Multichannel Active Vibration Isolation
,”
IEEE Trans. Control Syst. Technol.
,
9
(
1
), pp.
93
100
.
8.
Subrahmanyan
P.
,
Williams
M.
, and
Trumper
D.
,
1998
, “
Active Vibration Isolation Design for a Photolithographic Stepper
,” Proc. 6th International Symposium on Magnetic Bearings, Cambridge, MA.
This content is only available via PDF.
You do not currently have access to this content.