• Title/Summary/Keyword: multiple controllers

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Digital Receding Time Horizon LQ Optimal Contour Control System (디지털 후퇴 유한시간 구간 LQ 최적 윤곽제어시스템)

  • Sim, Young-Bok;Lee, Gun-Bok
    • Transactions of the Korean Society of Machine Tool Engineers
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    • v.15 no.6
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    • pp.105-113
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    • 2006
  • This work is concerned with the development of digital contouring controller for multi-axial servosystems. Digital optimal contouring controller is proposed to coordinate each of the controllers of multiple feed drives and specifically improve the contouring performance. The optimal control formation includes the contour error explicitly in the performance index to be minimized. The contouring control is exercised for straight line and circular contours. Substantial improvement in contouring performance is obtained for a range of contouring conditions. Both steady state and transient error measures have been considered. The simulation study presented has established the potential of the proposed controller to improve contouring performance.

Indirect Vector Control of Induction Motor using Nonlinear Observer (비선형 관측기에 의한 유도전동기 간접 벡터제어)

  • 정삼용;이진섭;서진연;김동휘;최연옥;조금배
    • Proceedings of the KIPE Conference
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    • 1998.07a
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    • pp.366-370
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    • 1998
  • Indirect vector control for induction motors requires the use of observers for estimation or observation of rotor flux magnitude and position. In this paper, authors discribe the induction motor vector control and introduce a nonlinear observer, named ELO(extended Luenberger Observer), without simulation results as a preliminary work for trial application. Normally, design of nonlinear observer need coordinate transfromation and linearization through solving the partial different equation. However, ELO requires minimal solution of nonlinear partial differential equation. Simulation was performed by under the enviroment of Matlab and Simulink without the proposed observer because we are still working. Simulation was performed with conventional flux observer, a dc-ac inverter by SVPWM technique, a vector controller armed with multiple PI controllers

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A HARMONIC-FREE CURRENT-LINK AC TO AC POWER SUPPLY: DYNAMIC ANALYSIS AND DESIGN

  • Karshenas, Hamid R.;Dewan, S.B.
    • Proceedings of the KIPE Conference
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    • 1998.10a
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    • pp.182-187
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    • 1998
  • In this paper, the dynamic analysis and design of an AC to AC power supply with DC current link is presented. Despite many advantages of such a structure, its application in fixed frequency power supplies has received very little attention in the literature. Different issues related to dynamic analysis of the proposed system are considered. These include a simple averaging technique for modeling switching function generators, the concept of Internal Model Controllers, and necessary condition to avoid multiple crossing in ramp comparison methods. Theoretical and experimental results obtained from a DSP-based laboratory type setup are presented.

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Design and Implementation of UCT/AGV Based Upon Steering Function (조향 함수를 고려한 UCT/AGV 설계 및 주행 기법에 관한 연구)

  • 윤경식;진태석;이장명
    • 제어로봇시스템학회:학술대회논문집
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    • 2000.10a
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    • pp.406-406
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    • 2000
  • In this study, as a part developing an unmanned container terminal (UCT), Ive designed and implemented an Autonomous Ground Vehicle (AGV) that can deliver containers in the port fast and safely as they are scheduled. It is preferable to research the intelligent UCT/AGV for delivering containers all day long without causing any trouble. For the sake of safe and fast AGV driving, we implemented a multiple-sensor system with vision, ultrasonic, and IR sensors and we adapted the hight-speed wireless LAN that satisfies the IEEE 802.11 Standard for hi-directional communication between the main processor in AGV and a host computer. The Pentium-III processor board mounted on the bottom frame in AGV combines and computes the information from sensors and controls the AGV driving. There are also the 80C196KC micro-controllers to control the actuating and steering motors. In addition, a steering function that is defined newly in this paper is heavily concerned in the mechanical design, and it plays an important role when AGV moves along a curve. Experimental results show the fast and safe delivery operations are possible with this UCT/AGV

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LQG design scheme for multiple vibration controllers in a data center facility

  • Kohiyama, Masayuki;Yoshida, Minako
    • Earthquakes and Structures
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    • v.6 no.3
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    • pp.281-300
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    • 2014
  • This study proposes a scheme to design control parameters for a data center facility with a vibration controller on its top floor and a secondary isolation device with its own vibration controller designed to protect vibration-sensitive computer equipment. The aim is to reduce the effects of acceleration and drift from an earthquake on computer servers placed on the isolation device that must operate during a seismic event. A linear elastic model is constructed and the evaluation function of the linear quadratic Gaussian (LQG) control is formulated. The relationship between the control parameters and the responses is examined, and based on the observations, a control parameter design scheme is constructed to reduce the responses of both the building and the computer server effectively.

Data Based Lower-Order Controller Design: Moment Matching Approach (데이터 기반 저차제어기 설계: 모멘트 정합 기법)

  • Kim, Young Chol;Jin, Lihua
    • The Transactions of The Korean Institute of Electrical Engineers
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    • v.61 no.12
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    • pp.1903-1910
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    • 2012
  • This paper presents a data based low-order controller design algorithm for a linear time-invariant process with a time delay. The algorithm is composed by combining an identification step based on open loop pulse test with a low-order controller design step to obtain the entire set of controllers achieving multiple performance specifications. The initial information necessary for this algorithm are merely the width and amplitude of a rectangular pulse, a controller of four types (PI, PD, PID, first-order), and design objectives. Various parametric approaches that have been developed are merged in the controller design algorithm. The resulting controller set satisfying the design objectives are displayed on the 2D and 3D graphics and thus it is very easy for us to pick a controller inside the admissible set because we can check the corresponding closed-loop performances visually.

Reference Point Projection Method for Improved Dynamics of Solar Array Hardware Emulation

  • Wellawatta, Thusitha;Choi, Sung-Jin
    • Proceedings of the KIPE Conference
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    • 2018.07a
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    • pp.126-128
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    • 2018
  • Solar array simulator (SAS) is a special DC power supply that regulates the output voltage or current to emulate characteristics of photovoltaic (PV) panels. Especially, the control of SAS is a challenging task due to the nonlinearity in the output curve, which is dependent on irradiance as well as temperature and is determined by panel materials. Conventionally, both current-mode control and voltage-mode control should be alternated by partitioning the operating curve into multiple sections, which is not only for the measurement noise problem with the feedback sensing but also for the control stability issue near the maximum power point. However, the occurrence of transition among different controllers may deteriorate the overall performance. To eliminate the mode transitions, a novel single controller scheme has been introduced in this paper, where the reference operating projection technique enables simple, smooth and numerically stable control. Theoretical consideration on the loop stability issue is discussed and the performance is verified experimentally for the emulation of a PV panel data in view of stability and response speed.

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Fuzzy Modeling Technique of Nonlinear Dynamical System and Its Stability Analysis (비선형(非線型) 시스템의 퍼지 모델링 기법과 안정도(安定度) 해석(解析)에 관한 연구)

  • Lee, J.T.;So, M.O.;Lee, S.S.;Ji, S.J.;Kim, T.W.
    • Proceedings of the KIEE Conference
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    • 1995.07b
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    • pp.801-803
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    • 1995
  • This paper presents the linearized fuzzy modeling technique of nonlinear dynamical system and the stability analysis of fuzzy control system. Firstly, the nonlinear system is partitionized by multiple linear fuzzy subcontrol systems based on fuzzy linguistic variables and fuzzy rules. Secondly, the disturbance adaptation controllers which guarrantee the global asymptotic stability of each fuzzy subsystem by an optimal feedback control law are designed and the stability analysis procedures of the total fuzzy control system using Lyapunov functions and eigenvalues are discussed in detail through a given illustrative example.

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On-line Frequency Estimation Based on Cascade Adaptive Notch Filter and Application to Active Noise Control

  • Kim, Sunmin;Park, Youngjin
    • 제어로봇시스템학회:학술대회논문집
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    • 1998.10a
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    • pp.81-84
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    • 1998
  • For ANC systems applied to aircrafts or passenger ships, engines from which reference signals are usually measured are located so far from seats where main part of controllers are placed. It can make feedforward ANC scheme difficult to implement or very costly. Feedback ANC algorithms which do not require reference signals and use error signals alone to update the filter, are usually sensitive to measurement noise ' and impulse noise. In this paper, reference signal needed for the feedforward control is not measured directly but generated with the estimated frequencies. Cascade adaptive notch filter (ANF), which has the low computational burden, is used to implement ANC system in real time. Several ANFs of order 2 are connected in series to estimate multiple sinusoids. Computer simulations and experiments in the laboratory for verifying efficacy of the proposed algorithm are carried out.

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A Study on Reliable Control System Using an Additive Redundant Adaptive Controller (가법적 중복적응 제어기를 이용한 신뢰성 제어 시스템에 관한 연구)

  • ;;Zeungnam Bien
    • The Transactions of the Korean Institute of Electrical Engineers
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    • v.39 no.3
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    • pp.301-311
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    • 1990
  • A multiple controller structure consisting of a typical feedback controller and an additive redundant controller is proposed for enhancing the reliability of the control system. For the case where the main controller is chosen as a pole assignment controller with input/output measurements and the redundant controller as the Model Reference Adaptive Controller (MRAC) whose reference model is the closed-loop combination of the plant and the main controller, it is proven that the tracking error between the command input and plant output converges to zero under failure in one of the controllers or parameter perturbations of the plant, and further that the reliability measured by Mean Time To Failure (MTTF) is greater than that of the system with only a single main controller. A simulation Example is provided to illustrate reliable operation of the proposed control system against the controller failure.

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