• Title, Summary, Keyword: linear time-varying system

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New Delay-dependent Stability Criteria for Uncertain Stochastic Systems with Time-varying Delays (시변 지연이 존재하는 불확실 스토캐스틱 시스템의 지연의존 안정성)

  • Kwon, Oh-Min;Park, Ju-Hyun;Lee, Sang-Moon
    • The Transactions of The Korean Institute of Electrical Engineers
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    • v.58 no.11
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    • pp.2261-2265
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    • 2009
  • In this paper, the problem of delay-dependent stability of uncertain stochastic systems with time-varying delay is considered. The uncertainties are assumed to be norm-bounded. Based on the Lyapunov stability theory, new delay-dependent stability criteria for the system are derived in terms of LMI(linear matrix inequality). Two numerical examples are given to show the effectiveness of proposed method.

Mixed Control of Agile Missile with Aerodynamic Fin and Thrust Vectoring Control (유도탄의 유도명령 추종을 위한 혼합제어기 설계 : 공력 및 추력벡터제어)

  • 이호철;최용석;송택렬;송찬호;최재원
    • Journal of Institute of Control, Robotics and Systems
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    • v.10 no.7
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    • pp.658-668
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    • 2004
  • This paper is concerned with a control allocation strategy using the dynamic inversion and the pseudo inverse control which generates the nominal control input trajectories. In addition, an autopilot design method is proposed by using time-varying control technique which is time-varying version of the pole placement of linear time-invariant system for an agile missile with aerodynamic fin and thrust vectoring control. The control allocation proposed in this paper is capable of extracting the maximum performance by combining each control effector, aerodynamic fin and thrust vectoring control. The adopted time-varying control technique for the autopilot design enhances the robustness of the tracking performance for a reference command. The main results are validated through the nonlinear simulations with aerodynamic data.

Utilization of the Filtered Weighted Least Squares Algorithm For the Adaptive Identification of Time-Varying Nonlinear Systems (적응 FWLS 알고리즘을 응용한 시변 비선형 시스템 식별)

  • Ahn Kyu-Young;Lee In-Hwan;Nam Sang-Won
    • The Transactions of the Korean Institute of Electrical Engineers D
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    • v.53 no.12
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    • pp.793-798
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    • 2004
  • In this paper, the problem of adaptively identifying time-varying nonlinear systems is considered. For that purpose, the discrete time-varying Volterra series is employed as a system model, and the filtered weighted least squares (FWLS) algorithm, developed for adaptive identification of linear time-varying systems, is utilized for the adaptive identification of time-varying quadratic Volterra systems. To demonstrate the performance of the proposed approach, some simulation results are provided. Note that the FWLS algorithm, decomposing the conventional weighted basis function (WBF) algorithm into a cascade of two (i.e., estimation and filtering) procedures, leads to fast parameter tracking with low computational burden, and the proposed approach can be easily extended to the adaptive identification of time-varying higher-order Volterra systems.

A theory of linear quasi-time invariant filters

  • Lee, Heyoung;Bien, Zeungnam
    • 제어로봇시스템학회:학술대회논문집
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    • pp.362-367
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    • 1996
  • In this paper, the eigenstructure of a class of linear time varying systems, termed as linear quasi-time invariant(LQTI) systems, is investigated. A system composed of dynamic devices such as linear time varying capacitors and resistors can be an example of the class. To effectively describe and analyze the LQTI systems, a generalized differential operator G is introduced. Then the dynamic systems described by the operator G are studied in terms of eigenvalue, frequency characteristics, stability and an extended convolution. Some basic attributes of the operator G are compared with those of the differential operator D. Also the corresponding generalized Laplace transform pair is defined and relevant properties are derived for frequency domain analysis of the systems under consideration. As an application example, a LQTI circuit is examined by using the concept of eigenstructure of LQTI system. The LQTI filter processes the sinusoidal signals modulated by some functions.

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Input-Output Gains of Linear Periodic Time-Varying Systems with Applications to Multirate Signal Processing (다중비 신호처리에 적용한 선형 주기적 시변 시스템의 입출력 이득)

  • 이상철;박계원
    • Journal of the Korea Institute of Information and Communication Engineering
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    • v.4 no.5
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    • pp.963-969
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    • 2000
  • In this paper, we define two input-output gains of linear periodic time-varying systems. One is the ratio of output with worst-case l2-norm over all inputs with unit 12-norm. It denotes G($\iota_2,\iota_2$.The other is the ratio of output with worst-case RMS value over all inputs with unit RMS value. It denotes G(RMS, RMS) .It is fact that these two gains are equivalent for linear time-invariant system. In this paper, we prove these two gains are also equivalent for linear periodic time-varying system. In addition, the relationship between two method of obtaining the generalized frequency responses for linear periodic time-varying system is derived. Finally, we apply the defined input-output gains to M-channel filter-bank which is multi-rate signal Processing system, used to speech coding. In the filter-bank, generally, aliasing distortion, magnitude distortion, and phase distortion are present. It is shown that these are kept small if the filter-bank is designed by a method that optimizes the gain G($\iota_2,\iota_2$ of an error system.

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A Consideration on the Applicability of the Discrete-Time Models of Linearly Time-Varying Systems to Digital Signal Processing (선형 시변 시스템에서의 이산 시간 모델의 신호처리 적용성 고찰)

  • Kwon, Soon-Man;Lee, Jong-Moo;Park, Min-Kook;Kim, Choon-Kyung;Cheon, Jong-Min
    • Proceedings of the KIEE Conference
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    • pp.267-269
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    • 2005
  • This paper describes a consideration on the sampling in linearly time-varying (LTV) systems in view of the convenience in digital signal processing. The relation between a continuous-time and a discrete-time system models is investigated for a simple linear time-invariant system. Based on the results of the investigation, we first consider discrete-time models for LTV systems, Then the simplicity of the models in terms of microprocessor-based digital signal processing is compared.

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Observer Design for Linear Neutral Systems with Time-Varying Delays (시변 시간 지연을 포함하는 선형 뉴트럴 시스템의 관측기 설계)

  • Song, Min-Kook;Joo, Young-Hoon;Park, Jin-Bae
    • Journal of Korean Institute of Intelligent Systems
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    • v.17 no.4
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    • pp.483-487
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    • 2007
  • This paper is concerned with the observer design problem for linear neutral systems with time-varying delays. The problem addressed is that of designing a full-order observer that guarantees the exponential stability of the error system. An effective algebraic matrix equation approach is developed to solve this problem. In particular, both observer analysis and design problems are investigated. Sufficient conditions for a linear neutral system to be stable are first established. Furthermore, an illustrative example is used to demonstrate the validity of the proposed design procedure.

A Linear Matrix Inequality Optima Control for the Tracking of an Autonomous Gliding Vehicle (자동 미끄럼 이동 로봇의 경로 추종을 위한 LMI 최적 제어 기법)

  • 이진우
    • 제어로봇시스템학회:학술대회논문집
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    • pp.335-335
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    • 2000
  • Applications such as unmanned aerial vehicles (UAVs), autonomous underwater vehicles (AUVs) and the time varying nature of their navigation, guidance and control systems motivate an integrated approach to trajectory general ion and trajectory tracking for autonomous vehicles. In this paper, an experimental testbed was designed for studying this integrated trajectory control approach. In this paper we apply the separating approach to an autonomous nonlinear vehicle system. A new linear matrix inequality based H$_{\infty}$ control technique for periodic time-varying systems is applied to the role of trajectory tracking. Trajectory general ion is accomplished by exploit ing the differential flatness property of the vehicle system; this at lows product ion of desired feasible nominal or reference trajectories from certain ″flat'system outputs. Simulation and experimental results are presented showing stable tracking of a periodic circular trajectory.

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New Stability Conditions for Positive Time-Varying Discrete Interval System with Interval Time-Varying Delay Time (구간 시변 지연시간을 갖는 양의 시변 이산 구간 시스템의 새로운 안정 조건)

  • Han, Hyung-Seok
    • The Journal of Advanced Navigation Technology
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    • v.18 no.5
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    • pp.501-507
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    • 2014
  • A dynamic system is called positive if any trajectory of the system starting from non-negative initial states remains forever non-negative for non-negative controls. In this paper, new sufficient conditions for asymptotic stability of the interval positive time-varying linear discrete-time systems with time-varying delay in states are considered. The considered time-varying delay time has an interval-like bound which has minimum and maximum delay time. The proposed conditions are established by using a solution bound of the Lyapunov equation and they are expressed by simple inequalities which do not require any complex numerical algorithms. An example is given to illustrate that the new conditions are simple and effective in checking stability for interval positive time-varying discrete systems.

Robust Pole Assignment Design for Linear Time-varying Uncertain Systems using LMI (LMI 기법을 이용한 시변 불확정성 선형 시스템의 강인 극점 배치 설계)

  • Kim, Jae-Sung;Ma, Sam-Sun;Kim, Jin-Hoon
    • Proceedings of the KIEE Conference
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    • pp.491-493
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    • 1999
  • In this paper, we consider the design of robust pole assignment for linear system. Considered uncertainty is time-varying uncertainty. Based on Lyapunov stability theorem and linear matrix inequality(LMI) we present the design result for pole assignment. Finally, we give some numerical examples to show the applicability and usefulness of our presented results.

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