REGULATOR PROBLEM FOR LINEAR SYSTEMS WITH
CONSTRAINTS ON CONTROL AND ITS INCREMENT
Fouad MESQUINE , Fernando TADEO , and Abdellah BENZAOUIA
University Cadi Ayyad, Faculty of Sciences
Department of Physics, Research unit Constrained Robust Regulation
B.P. 2390, Marrakesh Morocco
E-mail: mesquine@ucam.ac.ma, benzaouia@ucam.ac.ma
Departamento de Ingenieria de Sistemas y Automatica
Univesidad de Valladolid, 47005 Valladolid, Spain.
E-mail: fernando@autom.uva.es
Abstract: This paper discusses the problem of constraints on both control and its increment
for linear systems in state space form, in both the continuous and discrete time domains. For
autonomous linear systems with constrained increment, necessary and sufficient conditions
are derived, such that the evolution of the system respects the incremental constraints. It
is also derived a pole placement technique to solve inverse problem, deriving stabilizing
state feedback controllers which respect constraints on both control and its increment. An
illustrative example shows the application of the method. Copyright c IFAC 2002.
Keywords: Keywords: Linear Systems, Constraints, Control, Increment, Positive Invariance,
Pole assignment
1. INTRODUCTION
Usually, real plants or physical plants are subject to
constrained variables. The most frequent constraints
are of saturation type, that is, limitations on the
magnitude of certain variables. Hence, this topic is
of continuing interest and one could cite, not ex-
haustively, (Benzaouia, and Burgat, 1988; Benzaouia,
and Hmamed, 1993; Benzaouia, and Mesquine, 1994;
Blanchini 1990;1999 and the references Therein).
Other type of constraints were introduced while con-
sidering predictive control (GPC) and practical ap-
plications that is incremental constraints (Dion, et
al.,1987; Clarke et al. 1987; Warwick, and Clarke,
1988). In fact, for some processes, the rate of variables
change is limited within certain bounds. These limits
can arise from physical constraints that, if exceeded,
could damage the process. From our knowledge, no
work has been published on incremental constraints
using state space representations. Henceforth, this pa-
per investigates the problem of stabilizing linear con-
tinuous and discrete time systems with constraints on
both control and control increment. Necessary and
sufficient conditions of positive invariance for incre-
mental domains with respect to autonomous systems
are given. Furthermore, a link is done between pole
assignment procedure and these conditions to find sta-
bilizing controllers by state feedback.
1.1 Notations:
If is a vector, denotes its derivative with
respect to time in the continuous time case or
in the discrete-time case. Further, for a scalar
we define and , and
then we note that
Copyright © 2002 IFAC
15th Triennial World Congress, Barcelona, Spain