Improved non-fragile feedback control for stochastic jump system based on observer and quantized measurement

https://doi.org/10.1016/j.jfranklin.2020.09.024Get rights and content

Abstract

This paper elaborates the topic of observer-based non-fragile mixed passivity and H control for stochastic Markovian jump system with mode-dependent time-varying delays and uncertain parameters via quantized measurements. Improved sufficient conditions are acquired via constructing a mode-dependent Lyapunov–Krasovskii (L–K) functional and using the free-weight matrix technique. A suitable observer-based non-fragile feedback controller is provided to guarantee stochastic stability of the closed-loop system. Two examples including an electrical RLC circuit are presented to illustrate the correctness of the proposed approach in this paper.

Introduction

Over the past a few decades, many scholars are attracted to the Markovian jump systems (MJS) in virtue of the superiority of expressing random changes for physical systems suitably [1], [2], [3], [4], [5]. A mass of satisfactory results have been obtained in the intensive study about stability analysis [6], [7], [8] and control synthesis [9], [10], [11], [12] for MJS. In practice, many dynamic systems are often corrupted by noise, therefore, the topics of Ito^ stochastic systems become hot, which can simulate various practical systems affected by certain types of environmental noise, see, [13], [14], [15]. When a Ito^ stochastic system encounters Markovian jump changes, a stochastic Markovian jump system (SMJS) is generated [16], [17].

In practical systems, time delays are often confronted, which tend to reduce the performance and even lead to the instability of the system [18], [19], [20], [21]. The topic of stability and controller design for SMJS with time delays has been extensively studied in recent years [22], [23], [24], [25]. To mention a few, a new criteria was established to show the stability of uncertain MJS with polytopic parameter uncertainties and delays in [23]; the issue of stability analysis for uncertain time-delay MJS was taken into account in [24], the mode-dependent state feedback controller was designed for stochastic Markovian jump delay systems based on LaSalle theorem in [25].

There exist quite small uncertainties that lead to the closed-loop system unstable in controller implementation. Thus, up till now, considerable topics of non-fragile controller have been researched [26], [27]. How to design an insensitive feedback controller has been the principal problem of this control scheme, see, [28], [29], [30], [31], [32], [33]. For instance, both additive and multiplicative controller uncertainties were considered in [28]; the issue of non-fragile controller based on average dwell-time method was investigated in [29].

Noting that it is often difficult to acquire the states of many dynamic systems directly in real fields. Fortunately, the constructed observer can be employed to estimate the system states. The observer-based controller is widely applied in many practical plants [34], [35], [36], [37], [38]. Based on observer, [34] designed a non-fragile controller for stochastic systems, [38] developed mixed passive and H control for a class of MJS. However, mode-independent delays, Ito^ stochastic effects and Markovian jump changes were not mentioned simultaneously in the above literature. According to our knowledge, the problem of observer-based non-fragile mixed passivity and H control for SMJS with mode-dependent time-varying delays and uncertain parameters has not been fully investigated yet.

On the other hand, it is worth mentioning that quantization of input signals or measurement output is indispensable in some practical cases, and quantization can cause undesirable effect on system performance even stability [39]. Thus, considering the limited communication capacity of many dynamic systems, how to mitigate quantization effect and realize quantization control effectively has always been a significant research topic [20], [37]. Very recently, many important results of quantized feedback control have been reported, see, [12], [16], [37] and the references therein. Given all that, this paper will address the issue of non-fragile mixed passivity and H control for SMJS with mode-dependent time-varying delays and uncertain parameters based on observer and quantized measurements.

The main contributions of this paper are summed up as follows:

(1) A non-fragile controller and a non-fragile observer are considered simultaneously, an improved mode-dependent and delay-dependent L-K functional is constructed in this paper.

(2) Time-varying delays τrt(t) for SMJS are mode-dependent, derivative constraint condition of τ˙rt=i(t)h<1 is extended to τ˙rt=i(t)h, thus, the constraint condition is more general than the most existed results.

(3) Quantized measurement is utilized to solve feedback control for delayed SMJS based on observer.

Notation: E(·) denotes the expectation operator; | · | represents the Euclidean vector norm; matrix Q>0 (Q0) refers to Q is positive definite (positive semidefinite); Sym(X) is defined as Sym(X)=X+XT; * expresses a term that is induced by symmetry expressions.

Section snippets

Problem formulation and preliminaries

We consider the following SMJS with time-varying delays:{dx(t)=[(A(rt)+ΔA(t,rt))x(t)+(Aτ(rt)+ΔAτ(t,rt))x(tτrt(t))+B1(rt)u(t)+D1(rt)ν(t)]dt+[(E(rt)+ΔE(t,rt))x(t)+(Eτ(rt)+ΔEτ(t,rt))x(tτrt(t)+B2(rt)u(t)]dω(t),y(t)=C1(rt)x(t)+C1τ(rt)x(tτrt(t)),z(t)=C2(rt)x(t)+C2τ(rt)x(tτrt(t))+B3(rt)u(t)+D2(rt)ν(t),where x(t)Rn is the state; y(t)Rp is the measured output; z(t)Rq is the controlled output; u(t)Rp is the control input; ν(t)Rm is the disturbance input and belongs to L2[0, ∞); ω(t) is a

Main results

Theorem 1

The delayed SMJS (13) with ν(t)=0 is said to be stochastically stable, if for all iS, there exist matrices Q>0, R>0, Z>0, J>0, Pi>0 and scalars τ > 0, μ > 0, h, δ > 0, such that:Πi=[Π11iΠ12iZ*Π22iZJ**ZR]<0whereΠ11i=j=1NπijPj+PiA˜i+A˜iTPi+(1+δτ)QZ+E˜iT(Pi+τZ)E˜i+τ2A˜iTRA˜i,Π12i=PiA˜τi+Z+JT+E˜iT(Pi+τZ)E˜τi+τ2A˜iTRA˜τi,Π22i=(1h)QZJJT+E˜τiT(Pi+τZ)E˜τi+τ2A˜τiTRA˜τi.

Proof

For the sake of simplicity, we define the drift term of the delayed SMJS (13) as f(t), wheref(t)=A˜iζ(t)+A˜τiζ(tτi(t))+D˜iν(

Simulation examples

Example 1 Consider the time-varying delay SMJS (1) with the following parameters:A1=[0.1000.1],A2=[0.2000.2],Aτ1=[1.10.200.5],Aτ2=[10.100.4],E1=[0.2000.2],E2=[0.3000.3],Eτ1=[0.2000.2],Eτ2=[0.3000.3],C11=[0.10.1],C12=[0.60.6],C1τ1=[0.50.5],C1τ2=[0.60.6],C21=[00.7],C22=[00.8],C2τ1=[00.7],C2τ2=[00.8],B11=[00.5]T,B12=[00.6]T,B21=[0.10.1]T,B22=[0.20.2]T,MP1=[1.50.1]T,MP2=[1.60.2]T,ML1=[0.10.1]T,ML2=[0.20.2]T,NA1=[0.10.1],NAτ1=[0.10.1],NE1=[0.10.1],NEτ1=[0.10.1],NA2=[0.20.2],NAτ2=[0.20.2

Conclusions

This paper has elaborated the topic of observer-based non-fragile mixed passivity and H control for SMJS with mode-dependent time-varying delays and uncertain parameters via quantized measurements. Improved sufficient conditions have been acquired via constructing a mode-dependent L–K functional and using the free-weight matrix technique. A suitable observer-based non-fragile feedback controller has been provided to guarantee stochastic stability of the closed-loop system. Two examples

Declaration of Competing Interest

The authors declare that they have no conict of interest.

Acknowledgments

The authors would like to thank the anonymous Referees and the Editors for their valuable comments and suggestions, which greatly improved the exposition and quality of the work. This work was partially supported by the National Natural Science Foundation of China under Grants 61773191, 61673169; Support Plan for Outstanding Youth Innovation Team in Shandong Higher Education Institutions under Grant 2019KJI010; the Natural Science Foundation of Shandong Province for Outstanding Young Talents in

References (39)

Cited by (3)

View full text