Given a probability space , where Ω is the sample space, F is the σ algebra of subsets of the sample space and P is the probability measure on F. Over this probability space , we consider the following uncertain linear stochastic systems with Markovian jump parameters and mode-dependent time delays:
(1)
where is the state; is the disturbance input which belongs to ; is the measurement; is the signal to be estimated; and , independent of the Markov process, is a one-dimensional standard Wiener process. E is a singular square matrix, and . , , , , , , , , , , , , , , , , , , , , , , , , are governed by the Markov process , and is symmetric. is a continuous-time Markovian process with right-continuous trajectories and taking values in a finite set with transition probability matrix given by
where , ; for is the transition rate from mode i at time t to mode j and . is the time-varying delay when the mode is in and satisfies
(2)
where , are known real constant scalars, . denotes a vector-valued initial continuous function defined on the interval .
When , let denote ; so, for each ,
(3)
where , , , , , , , , , , , , , , , , , , , , , , , , are known real constant matrices describing the nominal system; , , , , , , , , , , , , , , , , , , , , , , , , are unknown matrices representing time-varying parameter uncertainties, and the admissible uncertainties are assumed to be modeled in the form
(4)
where , , , , , , , , , are known real constant matrices and is the uncertain time-varying matrix satisfying .
The vector-valued nonlinear functions f, , are assumed to satisfy the following sector-bounded conditions:
(5)
where are known real constant matrices, and , are symmetric positive definite matrices.
Remark 1 When E is a unit matrix, , , , , , , , , , , , , , , , , , , , , , , , , , , , , , , , , , system (1) was studied in [10]. The system in this paper is a class of stochastic time-delay systems broader than others.
In this paper, we consider a full-order filter with the following form:
where is the filter state and is the estimated vector, , , , , , are the desired filter matrices to be designed, may be a singular square matrix, , , , , , are the filter gain variations with the following form:
(8)
where , , , , are known real constant matrices and is unknown time-varying matrix function satisfying .
Remark 2 When is a unit matrix, and , , , , , the filter (6) was studied in [9]. The objective in this paper improves the function of the filter.
Applying this filter to system (1), we obtain the following filtering error system:
(9)
where
Denote , in this article, we focus our attention on the quadratic supply rate
where Q, S, R are appropriately dimensioned, and Q, R are symmetric matrices.
Definition 1 [18]
If filtering error system (9) is asymptotically stable and for all and , there exists such that the following inequality is well defined, then
(10)
Definition 2 Given a set of suited dimension real matrices Q, S, R, where Q, R are symmetric matrices, system (6) is called a robust dissipative filter of uncertain system (1) if there exist , , , , , such that
-
(a)
the augmented system (9) with is robust asymptotically stable for all uncertainties;
-
(b)
the filtering error system is strict robust dissipative.
Our aim is to determine parameters , , , , , such that system (6) is a robust dissipative filter for uncertain system (1).
Lemma 1 [8]
Given a set of suited dimension real matrices Q, H, E, Q is a symmetric matrix, such that
for all
F
satisfies
if and only if there exists
such that
Lemma 2 (Schur complement)
Given a symmetric matrix , where , the following three conditions are equivalent:
-
(i)
;
-
(ii)
, ;
-
(iii)
, .