• Title, Summary, Keyword: time-delayed perturbation

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Stability Bounds of Delayed Time-varying Perturbations of Discrete Systems (이산시스템에서 시간지연을 갖는 시변 상태 지연 섭동의 안정 범위에 관한 연구)

  • Lee, Dal-Ho;Han, Hyung-Seok
    • Journal of Institute of Control, Robotics and Systems
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    • v.13 no.2
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    • pp.147-153
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    • 2007
  • The stability robustness problem of linear discrete-time systems with delayed time-varying perturbations is considered. Compared with continuous time system, little effort has been made for the discrete time system in this area. In the previous results, the bounds were derived for the case of non-delayed perturbations. There are few results for delayed perturbation. Although the results are for the delayed perturbation, they considered only the time-invariant perturbations. In this paper, the sufficient conditions for stability can be expressed as linear matrix inequalities(LMIs). The corresponding stability bounds are determined by LMI(Linear Matrix Inequality)-based algorithms. Numerical examples are given to compare with the previous results and show the effectiveness of the proposed results.

Robust stability for discrete-time systems with delayed perturbations

  • Park, Juhyun;Rhee, Bongjae;Won, Sangchul
    • 제어로봇시스템학회:학술대회논문집
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    • pp.972-975
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    • 1996
  • This paper presents a sufficient condition for robust stability of discrete-time systems with delayed nonlinear perturbations. Using state evolution method, the bound on the norms of nonlinear perturbation which guarantees the exponential stability of the systems, is found. The numerical example is given to illustrate the results.

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Performance and Robustness of Discrete Perturbation Observer

  • Sangjoo Kwon;Chung, Wan-Kyun;Youngil Youm
    • 제어로봇시스템학회:학술대회논문집
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    • pp.31.5-31
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    • 2001
  • In conventional perturbation estimators such as disturbance observers(DOB) [1, 2] or time-delayed controllers(TDC) [3{5}, the low pass filter(so-called Q-filter) plays an important role in the stability and performance. However, a general design guideline or analysis for the Q-filter has not been researched yet. In this paper, a guideline for the design of discrete Q-filter is suggested in terms of the analysis of the relationship between the filter parameters and stability performance robustness in discrete-time domain. The analysis clarifies the discrete-time effect of the perturbation estimator and provides a transparent relationship between performance and robustness depending ...

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PERMANENCE FOR THREE SPECIES PREDATOR-PREY SYSTEM WITH DELAYED STAGE-STRUCTURE AND IMPULSIVE PERTURBATIONS ON PREDATORS

  • Zhang, Shuwen;Tan, Dejun
    • Journal of applied mathematics & informatics
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    • v.27 no.5_6
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    • pp.1097-1107
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    • 2009
  • In this paper, three species stage-structured predator-prey model with time delayed and periodic constant impulsive perturbations of predator at fixed times is proposed and investigated. We show that the conditions for the global attractivity of prey(pest)-extinction periodic solution and permanence of the system. Our model exhibits a new modelling method which is applied to investigate impulsive delay differential equations. Our results give some reasonable suggestions for pest management.

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A Stability Region of Time-varying Perturbations by Using Generalized Eigenvalue Problem (일반화된 고유치 문제를 이용한 시변 섭동의 안정 범위)

  • Lee, Dal-Ho;Han, Hyung-Seok
    • Journal of Institute of Control, Robotics and Systems
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    • v.11 no.11
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    • pp.901-906
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    • 2005
  • The stability robustness problem of continuous linear systems with nominal and delayed time-varying perturbations is considered. In the previous results, the entire bound was derived only for the overall perturbations without separation of the perturbations. In this paper, the sufficient condition for stability of the system with two perturbations, which are nominal and delayed, is expressed as linear matrix inequalities(LMIs). The corresponding stability bounds fer those two perturbations are determined by LMI(Linear Matrix Inequality)-based generalized eigenvalue problem. Numerical examples are given to compare with the previous results and show the effectiveness of the proposed.

NUMERICAL ANALYSIS OF PRESSURE PERTURBATION OF DELTA WING VORTEX FLOW AT A HIGH ANGLE OF ATTACK (고 받음각 ONERA 70도 삼각날개 와류 유동의 압력 섭동 분석)

  • Son, M.S.;Sa, J.H.;Park, S.H.;Byun, Y.H.
    • Journal of computational fluids engineering
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    • v.20 no.2
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    • pp.73-80
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    • 2015
  • Delayed Detached-Eddy Simulation was conducted to investigate surface pressure coefficient distribution and surface pressure fluctuation over an ONERA 70-degree delta wing at a high angle of attack. Time-averaged surface pressure distribution is directly affected by the primary vortices, whereas the pressure fluctuation is influenced by the unsteady fluctuating boundary layer over the surface. And pressure coefficient, velocity, pressure fluctuation, and turbulent kinetic energy were analyzed along the vortex core in order to investigate the process of vortex breakdown. Consequently, strong pressure fluctuations were found where the vortex breakdown was occurred at x~620 mm. The turbulent kinetic energy abruptly increased and followed after the vortex breakdown.

Comparison of Muscle Onset Times During Perturbation Between Subjects With and Without Work-Related Chronic Low Back Pain (직업성 만성요통 환자와 정상성인에서 동요 유발 시 근 수축 개시시간 비교)

  • Roh, Kyung-Sun;Kwon, Oh-Yun;Yi, Chung-Hwi;Jeon, Hye-Seon
    • Physical Therapy Korea
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    • v.14 no.2
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    • pp.21-28
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    • 2007
  • The purpose of this study was to compare the onset times of muscle activities and the order of muscle firing in erector spinae, multifidus, rectus abdominis and biceps brachii during perturbation between subjects with and without work-related chronic low back pain (LBP). Twenty-nine subjects, 14 with and 15 without LBP, participated in this study. The muscle responses were measured by surface EMG (electromyography) during perturbation in eye opened and eye closed conditions. The EMG onset times of the erector spinae, multifidus, rectus abdominis and biceps brachii were similar between groups in eye closed condition. But the onset times of the erector spinae, multifidus, rectus abdominis were significantly delayed in subjects with LBP in eye opened condition. The results provide an evidence for impaired feed-forward control of the trunk muscles in subjects with LBP. Further studies are needed to identify whether the impaired feed-forward control of the trunk muscles is the contributing factor to LBP.

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