Authors:
Lamia Ben Jemaa,
Edward J. Davison,
Volume: 1, Page 3708 Paper number 59
Abstract:
Fundamental limitations for error tracking/regulation are obtained
for the robust servomechanism problem (RSP) for discrete time periodic
systems. In studying this problem, the RSP for a multi-input/multi-output
discrete time system is considered. Application of these results
is then made to the ``periodic system robust servomechanism problem'',
and explicit expressions for the limiting costs for error tracking
regulation are obtained. These limitations can be characterized completely
by the number and location of the non-minimum phase transmission zeros.
Authors:
Naohisa Otsuka,
Volume: 1, Page 3715 Paper number 68
Abstract:
In this paper necessary conditions and / or sufficient conditions for
the solvability of the disturbance-rejection problem with dynamic compensator
which was investigated by Grasselli and Longhi is given for linear
fÖ-periodic discrete-time systems without assuming that the order
of dynamic compensator is equal to that of system plant. Further,
the minimal order of dynamic compensator which is necessary for the
solution of the problem is also investigated under the assumption that
the disturbance map does not depent on the time.
Authors:
S.E. Benton,
Eric Rogers,
David H. Owens,
Volume: 1, Page 3721 Paper number 1125
Abstract:
Repetitive processes are a distinct class of 2D systems of both practical
and theoretical interest. Their essential characteristic is repeated
sweeps, termed passes, through a set of dynamics defined over a finite
duration with explicit interaction between the outputs, or pass profiles,
produced as the process dynamics evolve. Experience has shown that
these processes cannot be studied/controlled by direct application
of existing theory (in all but a few very restrictive special cases).
This fact, and the growing list of applications areas, has prompted
an on-going research programme into the development of a `mature' systems
theory for these processes into reliable generally applicable controller
design algorithms. This paper develops stability tests for a sub-class
of so-called differential linear repetitive processes in the presence
of a general set of initial conditions, where it is known that the
structure of these conditions is critical to their stability properties.
Authors:
Hakan Köroglu,
Ömer Morgül,
Volume: 1, Page 3727 Paper number 1039
Abstract:
Linear Quadratic (LQ) controller design is considered for continuous-
time systems with harmonic signals of known frequencies and it is shown
that the design is reducible to an interpolation problem. All LQ optimal
loops are parametrized by a particular solution of this interpolation
problem and a (free) stable/proper transfer function. The appropriate
choice of this free parameter for optimal stability robustness is formulated
as a multiobjective design problem and reduced to a Nevanlinna-Pick
interpolation problem with some interpolation points on the boundary
of the stability domain. Using a related result from the literature,
it is finally shown that, if there is sufficient penalization on the
power of the control input, the level of optimum stability robustness
achievable with LQ optimal controllers is the same as the level of
optimum stability robustness achievable by arbitrary stabilizing controllers.
Authors:
Keliang Zhou,
Danwei Wang,
Volume: 1, Page 3733 Paper number 1277
Abstract:
In this paper, a repetitive learning control (RC) scheme is proposed
for const-voltage const-frequency (CVCF) pulsewidth modulated (PWM)
AC/DC converter. The repetitive controller is designed to force periodic
tracking error approach zero asymptotically. The design theory of repetitive
learning controller is described systematically and the stability analysis
of overall system is discussed. The proposed DC/AC converter offers
minimized voltage total harmonics distortion (THD) under parameter
uncertainties and load disturbances. Simulation results are provided
to illustrate the validity of the proposed scheme.
Authors:
Manabu Yamada,
Zaier Riadh,
Yasuyuki Funahashi,
Volume: 1, Page 3739 Paper number 1610
Abstract:
In this paper, a new approach to regulate quickly any periodic signals
with multiple periods is proposed and a useful multiple repetitive
control system is presented from the practical viewpoint. The contributions
are as follows: First, the dead-time length of the periodic generator
is reduced to the sum of all the periods. Therefore, the proposed multiple
repetitive controller not only can be implemented with much less memory
element than the previous ones but also can provide much faster convergence
of the controlled error to zero. Secondly, the proposed repetitive
controller not only can assure the stability of the multiple repetitive
control system but also can assign all poles of the closed loop system
on the disk with a given radius whose center is the origin. Thirdly,
the proposed controller is obtained in an explicit form and the design
method requires to solve no equation. The design effort is very small
even if the periods are very large. Fourthly, the robustness of the
system is improved by introducing a low pass zero phase filter. Finally,
the effectiveness is demonstrated by simulation.
Authors:
Hiroshi Fujimoto,
Yoichi Hori,
Volume: 1, Page 3745 Paper number 1439
Abstract:
In this paper, novel multirate feedback controllers are proposed for
digital control systems with relatively long sampling period. The
proposed controllers achieve vibration suppression and disturbance
rejection even in the semi-Nyquist frequency region. First, the continuous-time
vibration suppression controller is exactly discretized by the multirate
sampling control based on the closed-loop characteristics. Second,
the multirate repetitive controllers are proposed both by the feedback
and feedforward approaches. Moreover, the inter-sample disturbance
rejection performance is optimized by the fast sampling approach.
The proposed controllers are applied to the settling and following
modes of hard disk drive, and the advantages of these approaches are
demonstrated by simulations.
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