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Stability Bound for Time-Varying Uncertainty of Time-varying Discrete Interval System with Time-varying Delay Time

시변 지연시간을 갖는 이산 구간 시변 시스템의 시변 불확실성의 안정범위

  • Han, Hyung-seok (Department of Electronic Engineering, Gachon University)
  • 한형석 (가천대학교 전자공학과)
  • Received : 2017.10.29
  • Accepted : 2017.11.29
  • Published : 2017.12.31

Abstract

In this paper, we consider the stability bound for uncertainty of delayed state variables in the linear discrete interval time-varying systems with time-varying delay time. The considered system has an interval time-varying system matrix for non-delayed states and is perturbed by the unstructured time-varying uncertainty in delayed states with time-varying delay time within fixed interval. Compared to the previous results which are derived for time-invariant cases and can not be extended to time-varying cases, the new stability bound in this paper is applicable to time-varying systems in which every factors are considered as time-varying variables. The proposed result has no limitation in applicable systems and is very powerful in the aspects of feasibility compared to the previous. Furthermore. the new bound needs no complex numerical algorithms such as LMI(Linear Matrix Inequality) equation or upper solution bound of Lyapunov equation. By numerical examples, it is shown that the proposed bound is able to include the many existing results in the previous literatures and has better performances in the aspects of expandability and effectiveness.

본 논문에서는 시변 지연시간이 있는 선형 이산 구간 시변 시스템의 지연 상태변수에 존재하는 불확실성 안정범위에 관한 것을 다룬다. 고려된 시스템은 지연 없는 상태변수에 대한 시스템 행렬이 구간범위에서 시변으로 변동하고, 지연 시간이 구간범위 내에서 시변인 지연 상태변수에 대하여 비구조화된 불확실성이 시변으로 존재하는 시스템이다. 기존의 많은 연구들이 시변에 대한 부분을 고려하지 못하고 시불변 경우에 대하여 얻어진 것에 반하여, 본 논문에서는 모든 요소를 시변으로 고려하여 새로운 안정범위를 도출하였다. 새로운 안정범위는 적용 가능한 시스템에 대한 제한이 없는 것으로 그 효용성이 기존의 결과 보다 우수하다. 제안된 범위는 복잡한 선형행렬부등식 혹은 리아프노프 방정식의 상한 해 한계를 이용하는 복잡한 과정이 필요하지 않다. 수치예제를 통하여 제안된 결과가 기존의 결과들을 포함할 수 있음을 보이고, 이들 보다 확장성과 효용성이 우수함을 확인한다.

Keywords

References

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