It is well known that the type of hold circuit used in a digital control scheme critically influences the position of the discrete-time zeros. Most digital control systems use a zero-order hold (ZOH). Nevertheless, there are more convenient alternatives to the use of a ZOH signal reconstruction device in certain digital control problems. A fractional order hold (FROH) circuit is proposed in this paper in order to manage a computer hard disk read–write head described as a second order system. Significant improvements in the transient performance of the closed-loop system are obtained with respect to the use of a ZOH when using a properly adjusted FROH device.
References
-
-
1)
-
M.J. BLACHUTA
.
On zeros of pulse transfer function.
IEEE Trans. Autom. Control
,
6 ,
1229 -
1234
-
2)
-
H.K. SUNG ,
S. HARA
.
Properties of sensitivity and complementary sensitivity functions singles input–output digital control systems.
Int. J. Control
,
6 ,
2429 -
2439
-
3)
-
B.C. Kuo
.
(1980)
Digital control systems.
-
4)
-
K.M. PASSINO ,
P.J. ANTSAKLIS
.
Inverse stable sampled low-pass systems.
Int. J. Control
,
6 ,
1905 -
1913
-
5)
-
K.J. Åstrom ,
P. Hagander ,
J. Sternby
.
Zeros of sampled systems.
Automatica
,
1 ,
31 -
38
-
6)
-
T. HAGIWARA ,
T. YUASA ,
M. ARAKI
.
Stability of the limiting zeros of sampled-data systems with Zero- and First-Order Holds.
Int. J. Control
,
6 ,
1325 -
1346
-
7)
-
M. M'SAAD ,
R. ORTEGA ,
I.D. LANDAU
.
Adaptive controllers for discrete-time systems with arbitrary zeros: an overview.
Automatica
,
4 ,
113 -
423
-
8)
-
R.H. MIDDLETON
.
Trade-offs in linear control system design.
Automatica
,
2 ,
281 -
292
-
9)
-
D.W. CLARKE
.
Self-tuning control of nonminimum-phase systems.
Automatica
,
5 ,
501 -
517
-
10)
-
K.J. ASTRÖM ,
B. WITTENMARK
.
Self-tuning controllers based on pole-zero placement.
IEE Proc. D, Control Theory and Appl.
,
3 ,
120 -
130
-
11)
-
R. Dorf
.
(1998)
Modern control systems.
-
12)
-
R. BARCENA ,
M. DE LA SEN ,
I. SAGASTABEITIA
.
Improving the stability properties of the zeros of sampled systems with Fractional order hold.
IEE Proc., Control Theory Appl.
,
4 ,
456 -
464
-
13)
-
G.F. Franklin ,
J.D. Powell ,
M. Workman
.
(1997)
Digital control of dynamic systems.
-
14)
-
K.J. Astrom ,
B. Wittenmark
.
(1995)
Adaptive control.
-
15)
-
ISHITOBI, M., ZHU, Q: `Zeros of sampled systems with fractional order hold implemented by zero order hold', IEEE International Conference on Intelligent processing systems, 1997, New York, 1, p. 698–702.
-
16)
-
K.J. Åström ,
B. Wittenmark
.
(1997)
Computer controlled systems. Theory and design.
-
17)
-
M. ISHITOBI
.
Stability of zeros of sampled systems with fractional order hold.
IEE Proc. Control Theory Appl.
,
3 ,
296 -
300
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