• Title/Summary/Keyword: variable structure system

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A Study on the Dynamic Behavior of a 2-step Variable Valve Switching System for Automotive Engines (자동차 엔진용 2단 가변밸브 기구의 스위칭 시스템 동적 거동에 관한 연구)

  • Kim, Dongil;Kim, Dojoong
    • Transactions of the Korean Society of Automotive Engineers
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    • v.22 no.6
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    • pp.39-48
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    • 2014
  • Variable valve actuation system is one of the widely used techniques to improve the fuel efficiency and power of automotive engines. 2-step variable valve actuation systems are also paid attention for the application to direct acting type valve train systems. Besides its advantages in size, weight, relatively simple structure, ets, however, 2-step variable valve actuation system has inherent disadvantages in dynamic instability of switching system to alter discontinuous lift modes. In this study, both experimental and analytical studies are performed to understand the dynamic behavior of a switching mechanism of a 2-step variable valve actuation system, and present a design method to improve its dynamic instability.

The Application of Fuzzy Reaching Law Control in AC Position Servo System

  • Yang Yangxi;Liu Ding
    • Proceedings of the KIPE Conference
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    • 2001.10a
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    • pp.360-364
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    • 2001
  • In this paper, a novel method of reaching law variable structure control based on fuzzy rules is present, which is that the reaching law parameters is on-line adjusted by fuzzy rules. This method is used in a digital ac position servo system, the experiment results show that the system designed by this method has both satisfactory quality and very smaller chattering.

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A study on the variable structure model following controller design of uncertain system (불확실한 시스템의 가변구조 모델 추종 제어기 설계에 관한 연구)

  • 박재홍;이형찬;양해원
    • 제어로봇시스템학회:학술대회논문집
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    • 1990.10a
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    • pp.155-160
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    • 1990
  • This paper presents the new VSMFC (variable structure model following control) algorithm of a system with parameter uncertainty. In contrast to the conventional approach, continuous control inputs am used instead of discontinous ones and modified reachability condition for sliding mode reduces a reaching phase and a newly proposed sliding surfaces are used for the robust control of uncertain system.

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Variable Speed SRM Drive System with Fuzzy Controller (퍼지제어기를 이용한 스윗치드 리럭탄스 전동기의 속도제어)

  • Kim, C.H.;Kwon, Y.A.;Kim, C.U.
    • Proceedings of the KIEE Conference
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    • 1994.07a
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    • pp.6-8
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    • 1994
  • Switched reluctance motor drive system is well known as a variable speed drive system because it has a simple motor structure and a simple driving circuit. Widely slotted photo interrupter has been investigated as a position sensor for SRM speed control because it has advantages of low cost and simple structure. However it has low resolution and it produces dead-time signal. This paper studies variable speed SRM drive system with slotted photo-interrupter. Controller in this study is constructed by using fuzzy controller that covers system nonlinearities and small perturbations in sufficiency. The performance of this system is evaluated through computer simulation and experiment results.

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An Electrohydraulic Position Servo Control Systems Using the Optimal Feedforward Integral Variable Structure Controller

  • Phakamach, Phongsak
    • 제어로봇시스템학회:학술대회논문집
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    • 2004.08a
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    • pp.936-941
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    • 2004
  • An Optimal Feedforward Integral Variable Structure or FIVSC approach for an electrohydraulic position servo control system is presented in this paper. The FIVSC algorithm combines feedforward strategy and integral in the conventional Variable Structure Control (VSC) and calculating the control function to guarantee the existence of a sliding mode. Furthermore, the chattering in the control signal is suppressed by replacing the sign function in the control function with a smoothing function. The simulation results illustrate that the purposed approach gives a significant improvement on the tracking performances when compared with some existing control methods, like the IVSC and MIVSC strategies. Simulation results illustrate that the purposed approach can achieve a zero steady state error for ramp input and has an optimal motion with respect to a quadratic performance index. Moreover, Its can achieve accurate servo tracking in the presence of plant parameter variation and external load disturbances.

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The Control of Large Scale System by Sliding Mode (슬라이딩 모드를 이용한 대규모 계통의 제어)

  • Chun, Hee-Young;Park, Gwi-Tae;Kuo, Chun Ping;Kim, Dong-Sik;Im, Hyeong-Yong
    • Proceedings of the KIEE Conference
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    • 1987.07a
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    • pp.190-194
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    • 1987
  • This paper describes a new method for control of large-scale system by sliding mode. The concepts of control to large-scale system on the basis of VSS(Variable Structure System) control theory are used to decompose a large control problem into a two-level algorithm such that each subsystem is stabilized with local discontinuous controllers and higher level corrective control is designed to take into account the effect of interaction among the subsystems. In this paper, we show that each subsystem is controlled with repect to local continuous and higher level corrective control. This algorithm can be easily applied to multi-variable control system and obtained a continuous control in comparison With variable structure control systems. Two numerical examples are discussed as illustrations.

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A Simulation Study of Position Control Performance of a Shape Memory Alloy-Actuated Flow Control Valve (형상기업합금을 이용한 유량제어밸브의 위치제어 적용 시뮬레이션)

  • Choi, Su-Hyun;Lee, Han-Suk;Kuk, Kum-Hoan
    • Journal of the Korean Society for Precision Engineering
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    • v.16 no.8
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    • pp.79-87
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    • 1999
  • In this study, a new type of flow control valve which is SMA actuated flow control valve is presented. The flow control valve is actuated by a small motion of shape memory alloy. The performance of this valve as a position control component is analyzed by computer simulation. A variable structure control technique is applied for the position control by the flow control valve. The position control performance of the valve is evaluated on the step responses of a PID control by a electrohydraulic servo valve. For the simulation study, first, the mathematical model of a hydraulic system, which is consisted of the flow control valve and a hydraulic cylinder, is formulated. This mathematical model and the designed variable structure control algorithm are then combined by the MATLAB software. The same sequence of work is carried out for the PID position control system with a electrohydraulic servo valve. The simulation results show the validity of the new type of flow control valve as a variable position control component.

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A Study on Optimal Polynomial Neural Network for Nonlinear Process (비선형 공정을 위한 최적 다항식 뉴럴네트워크에 관한 연구)

  • Kim, Wan-Su;Oh, Sung-Kwun;Kim, Hyun-Ki
    • Proceedings of the KIEE Conference
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    • 2005.10b
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    • pp.149-151
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    • 2005
  • In this paper, we propose the Optimal Polynomial Neural Networks(PNN) for nonlinear process. The PNN is based on Group Method of Data Handling(GMDH) method and its structure is similar to feedforward Neural Networks. But the structure of PNN is not fixed like in conventional Neural Networks and can be generated. The each node of PNN structure uses several types of high-order polynomial such as linear, quadratic and modified quadratic, and is connected as various kinds of multi-variable inputs. The conventional PNN depends on experience of a designer that select No. of input variable, input variable and polynomial type. Therefore it is very difficult a organizing of optimized network. The proposed algorithm identified and selected No. of input variable, input variable and polynomial type by using Genetic Algorithms(GAs). In the sequel the proposed model shows not only superior results to the existing models, but also pliability in organizing of optimal network. Medical Imaging System(MIS) data is simulated in order to confirm the efficiency and feasibility of the proposed approach in this paper.

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Variable Structure Control Design Based on Eigenvalues Assignment of Sliding Mode (슬라이딩 모드 고유치 설정에 기반을 둔 가변구조 제어 설계)

  • Hong, Yeon-Chan;Lee, Tae-Bong
    • Journal of the Korea Academia-Industrial cooperation Society
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    • v.11 no.6
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    • pp.2207-2213
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    • 2010
  • A new scheme for variable structure control design which is based on eigenvalues assignment of sliding mode is developed. In conventional methods, generally, specific type of system matrix like canonical or regular form is required to construct a switching surface. Furthermore, the methods are not explicit. The new method in this paper solved the problems. No special type of system matrix is required and very explicit. It is shown that the switching surface can be constructed and determined uniquely without any dependency on the system form. The proposed method is based on the fact that the dynamics of sliding mode is determined by system zeros. Finally, a numerical example is given to verify the validity of the results studied in this paper.

A Study on the Variable -Structure Control Using New Switching Variables (새로운 스위칭 변수를 이용한 가변구조제어에 관한 연구)

  • 이주장;이흥규;이병일
    • Journal of the Korean Institute of Telematics and Electronics
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    • v.25 no.12
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    • pp.1586-1593
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    • 1988
  • A new control scheme for the variable-structure control system using new time-varying switching variable is presented in this paper. It is proposed to have new algorithm for reducing the reaching time on a switching hyperplane by modifying the Morgan's algorithm. From the results of the simulation, it is concluded the proposed control algorithm yields smaller control inputs (without disturbance) and ripples (with disturbance) than that obtained by Morgan's algorithm in the steady-state. This control algorithm can be applied to proper control systems having sensitive effects on disturbances, due to the robustness.

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