• Title, Summary, Keyword: Discrete-time system

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Discrete-Time Sliding Mode Controller Design for Scanner system (Scanner System을 위한 Discrete-Time Sliding Mode Controller 설계)

  • 이충우;정정주
    • 제어로봇시스템학회:학술대회논문집
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    • pp.172-172
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    • 2000
  • In this paper, we propose a new discrete-time sliding mode controller for reference tracking. Stability of tracking error is analyzed. Design method of sliding surface for tracking control is proposed. Simulation and experimental results are included to show the effectiveness of the proposed method.

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Eigenvalue Sensitivity Analysis of Discrete Power Systems Including Generator Controllers and TCSC (발전기 제어장치와 TCSC를 포함하는 이산 전력시스템의 고유치 감도해석)

  • Kim, Deok-Young
    • Journal of the Korean Institute of Illuminating and Electrical Installation Engineers
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    • v.24 no.12
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    • pp.193-200
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    • 2010
  • In this paper, the eigenvalue sensitivity analysis is calculated in the power system which is including both generator controllers such as Exciter, PSS and thyristor controlled FACTS devices in transmission lines such as TCSC. Exciter and PSS are continuously operating controllers but TCSC has a switching device which operates non-continuously. To analyze both continuous and non-continuous operating equipments, the RCF method one of the numerical analysis method in discrete time domain is applied using discrete models of the power system. Also the eigenvalue sensitivity calculation algorithm using state transition equations in discrete time domain is devised and applied to a sampled system. As a result of simulation, the eigenvalue sensitivity coefficients calculated using discrete system models in discrete time domain are changed periodically and showed different values compared to those of continuous system model in time domain by the effect of periodic switching operations of TCSC.

Determining of the Sampling Time and Adjusting PID Coefficients in a Discrete System (이산 시스템에서 샘플링 시간의 설정 및 PID 계수 조정)

  • Choi, Goon-Ho
    • Journal of the Semiconductor & Display Technology
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    • v.16 no.4
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    • pp.46-51
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    • 2017
  • Recent controller design techniques often discretize the target system and implement a discrete controller that is digitized to match the target system. When constructing such a discrete system, it is necessary to first determine the sampling time. The smaller the sampling time is, the more advantageous it can be made similar to the original system, but the cost is a problem when realizing such a configuration as hardware. On the other hand, the longer the time, the more different the system is from the original system, and eventually the control becomes impossible. In this paper, we consider the above problem and propose a more logical approach to determine the sampling time in the discrete system and investigate the relation with the differential controller. We also apply this process to a nonlinear system called ARAGO disc and verify its validity through computer simulation.

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Characteristics of One Step Advanced Discrete Time D-Control with Time Delay in Noncolocated Flexible System (비병치 유연계의 시간지연 이산제어에서 한스텝선행 미분제어기의 특성)

  • Kang, Min-Sig
    • Transactions of the Korean Society of Mechanical Engineers
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    • v.17 no.7
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    • pp.1678-1685
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    • 1993
  • This paper considers a time delay control of noncolocated flexible mechanical systems in discrete time domain. A stability criterion suggested in the previous paper is,extended in the consideration of infinite mode property of flexible systems and finite control sampling frequency. Based on the stability criterion, the one step advanced discrete time derivative control is suggested, which can stabilize infinite number of modes of a flexible system. The sensitivity analysis shows the robustness of the one step advanced control to the system parameter uncertainties and time delay errors. Application to a simply supported beam verifies the extended stability criterion and the effectiveness of the one step advanced D-control.

Modeling and Control of Intersection Network using Real-Time Fuzzy Temporal Logic Framework (실시간 퍼지 시간논리구조를 이용한 교차로 네트워크의 모델링과 제어)

  • Kim, Jung-Chul;Lee, Won-Hyok;Kim, Jin-Kwon
    • Journal of Institute of Control, Robotics and Systems
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    • v.13 no.4
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    • pp.352-357
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    • 2007
  • This paper deals with modeling method and application of Fuzzy Discrete Event System(FDES). FDES have characteristics which Crisp Discrete Event System(CDES) can't deals with and is constituted with the events that is determined by vague and uncertain judgement like biomedical or traffic control. We proposed Real-time Fuzzy Temporal Logic Framework(RFTLF) to model Fuzzy Discrete Event System. It combines Temporal Logic Framework with Fuzzy Theory. We represented the model of traffic signal systems for intersection to have the property of Fuzzy Discrete Event System with Real-time Fuzzy Temporal Logic Framework and designed a traffic signal controller for smooth traffic flow. Moreover, we proposed the method to find the minimum-time route to reach the desired destination with information obtained in each intersection. In order to evaluate the performance of Real-time Fuzzy Temporal Logic Framework model proposed in this paper, we simulated unit-time extension traffic signal controller model of the latest signal control method on the same condition.

Discrete Time Modeling of the Front Suspension System with Nonlinearity (비선형성을 갖는 전륜 현가장치의 이산시간 모델링)

  • 이병림;이재응
    • Transactions of the Korean Society of Automotive Engineers
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    • v.8 no.6
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    • pp.156-164
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    • 2000
  • In this study, a discrete time model for a simplified front wheel suspension system which has nonlinear dampling and stiffness property is introduced. The model is estimated from the discrete data which are generated based on the real car parameter. The performance of the proposed method is evaluated through numerical simulation, and the simulation results show that the proposed method can estimate the nonlinear behavior of the suspension system very well.

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The identification of continuous-time systems within a closed-loop

  • Bae, Chul-Min;Wada, Kiyoshi;Imai, Jun
    • 제어로봇시스템학회:학술대회논문집
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    • pp.157-160
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    • 1996
  • Physical systems axe generally continuous-time in nature. However as the data measured from these systems is generally in the form of discrete samples, and most modern signal processing is performed in the discrete-time domain, discrete-time models are employed. This paper describes methods for estimating the coefficients of continuous-time system within a closed loop control system. The method employs a recursive estimation algorithm to identify the coefficients of a discrete-time bilinear-operator model. The coefficients of the discrete-time bilinear-operator model closely approximate those of the corresponding continuous-time Laplace transform transfer function.

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The Simulation of Myocardium Conduction System using DEVCS and Discrete Time CAM (DEVCS 및 Discrete Time CAM을 이용한 심근 전도 시스템의 시뮬레이션)

  • Kim, K.N.;Nam, G.K.;Son, K.S.;Lee, Y.W.;Jun, K.R.
    • Proceedings of the KOSOMBE Conference
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    • v.1997 no.05
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    • pp.150-155
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    • 1997
  • Modelling and Simulation of the activation process for the myocardium is meaningful to understand special excitation conduction system in the heart and to study cardiac functions. In this paper, we propose two dimensional cellular automata model for the activation process of the myocardium and simulated by means of discrete time and discrete event algorithm. In the model, cells are classified into anatomically similar characteristic parts of heart; SA node, internodal tracks, AV node, His bundle, bundle branch and four layers of the ventricular muscle, each of which has a set of cells with preassigned properties, that is, activation time, refractory duration and conduction time between neighbor cell. Each cell in this model has state variables to represent the state of the cell and has some simple state transition rules to change values of state variables executed by state transition function. Simulation results are as follows. First, simulation of the normal and abnormal activation process for the myocardium has been done with discrete time and discrete event formalism. Next, we show that the simulation results of discrete time and discrete event cell space model is the same. Finally, we compare the simulation time of discrete event myocardium model with discrete time myocardium models and show that the discrete event myocardium model spends much less simulation time than discrete time myocardium model and conclude the discrete event simulation method Is excellent in the simulation time aspect if the interval deviation of event time is large.

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Optimal Design of Discrete Time Preview Controllers for Semi-Active and Active Suspension systems

  • Youn, Il-Joong
    • Journal of Mechanical Science and Technology
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    • v.14 no.8
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    • pp.807-815
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    • 2000
  • In this paper, modified discrete time preview control algorithms for active and semi-active suspension systems are derived based on a simple mathematical 4 DOF half-car model. The discrete time preview control laws for ride comfort are employed in the simulation. The algorithms for MIMO system contain control strategies reacting against body forces that occur at cornering, accelerating, braking, or under payload, in addition to road disturbances. Matlab simulation results for the discrete time case are compared with those for the continuous time case and the appropriateness of the discrete time algorithms are verified by the of simulation results. Passive, active, and semi-active system responses to a sinusoidal input and an asphalt road input are analysed and evaluated. The simulation results show the extent of performance degradation due to numerical errors related to the length of the sampling time and time delay.

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