that the closed-loop system (3) is a stable regular
state-space system. This completes the proof.
The sufficiency part of the proof of Theorem 1
provides a construction of the matrix D of state-
derivative feedback which stabilizes the system (1).
The major steps of this construction are given
below.
Construction
Given: A, B
Find: D
Step 1: Check conditions (a) and (b) of Theorem
1. If these conditions are satisfied go to Step 2. If
conditions (a) and (b) are not satisfied go to Step 4.
Step 2: Stabilizability of the pair (A, B) implies
that the pair (A, B) is either controllable or
uncontrollable with stable uncontrollable
eigenvalues. If the pair (A, B) is controllable, then
from Lemma 7 it follows that there exists a matrix
F over R such that
det[ A BF] = A BF] = χ(s)
where be an arbitrary monic and strictly
Hurwitz polynomial over R[s] of degree
n.
The
matrix F can be calculated using known methods
for the solution of pole assignment problem by state
feedback [7].
If the pair (A,B) is uncontrollable with stable
uncontrollable eigenvalues then from Lemma 8 and
Lemma 9 it follows that there exists a matrix T
such that
AT =
B =
The pair is controllable and the matrix
is Hurwitz stable. Controllability of the pair
and Lemma 7 imply the existence of a
matrix over R of appropriate dimensions such
that
det] φ(s)
where φ(s) is an arbitrary monic, strictly Hurwitz
polynomial over R[s] of appropriate degree. The
matrix can be calculated using known methods
for the solution of pole assignment by state feedback
[7]. According to (49) the matrix [A+BF] with F
given by
F= [, 0]
is Hurwitz stable.
Step 3: Put
D = F[A BF]-1
Step 4: The stabilization problem by state-
derivative state feedback has no solution.
5 Conclusions
In this paper the stabilization problem by state-
derivative feedback for linear time-invariant
continuous-time systems is studied and completely
solved. The proof of the main results of this paper is
constructive and furnishes a procedure for the
computation of stabilizing state-derivative feedback.
As far as we know the stabilization problem by
state-derivative feedback for linear time-invariant
continuous-time systems in its full generality, is still
an open problem. This clearly demonstrates the
originality of the contribution of the main results of
this paper with respect to existing results.
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WSEAS TRANSACTIONS on SYSTEMS and CONTROL
DOI: 10.37394/23203.2023.18.7