• Title/Summary/Keyword: robustness

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LQG/LTR methods for systems with input delay (입력에 시간지연이 있는 시스템에 대한 LQG/LTR 기법)

  • 권욱현;이상정
    • 제어로봇시스템학회:학술대회논문집
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    • 1986.10a
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    • pp.356-361
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    • 1986
  • This paper presents robustness properties of LQ regulators for input-delayed systems. Using frequency-domain representations, the Kalman inequality concerning the return-difference matrix is derived. The stability margins of LQ regulators are investigated using the Kalman inequality when the open-loop system is stable. In order to obtain stability margins a upper bound of the solution of LQ Riccati equations is derived. Finally, the LQG/LTR method to improve the robustness of LQG regulators is obtained and illustrated with an example.

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A study on improvement of robustness in adaptive control (적응제어에 있어서의 robustness 개선을 위한 방법에 관한 연구)

  • 김홍필;민병태;양해원
    • 제어로봇시스템학회:학술대회논문집
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    • 1987.10b
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    • pp.182-184
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    • 1987
  • When a .epsilon.$_{1}$-modification is applied to a plant with unmodeled dynamics and bounded output disturbance, the output error seems to be relatively large. A .epsilon.$_{1}$-modification with the same switching action as in the switching a modification is proposed to reduce the output proposed adaptive control scheme is to a second-oder plant and it can be asserted that the control objective is satisfied.

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The Robustness of Continuous Implicit Self Tuning Controller (연속치 내재형 자기동조 제어기의 강인성)

  • Lee, Bong-Kuk;Huh, Uk-Youl
    • Proceedings of the KIEE Conference
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    • 1990.07a
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    • pp.496-499
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    • 1990
  • In this paper, the robustness of implict self tunning controller on the continuous time system is investigated. Continuous time exponentially weighted least square algorithm is used for estimating the system parameters. The pole-zero placement method is adapted for the control algorithm. On considering the control weighting factor and realizability filter the effects of unmodeled dynamics of the plant are examined by the simulation.

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An Adaptive Control Method of Robot Manipulators using RBFN (RBFN을 이용한 로봇 매니퓰레이터의 적응제어 방법)

  • 이민중;최영규;박진현
    • 제어로봇시스템학회:학술대회논문집
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    • 2000.10a
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    • pp.420-420
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    • 2000
  • In this paper, we propose an adaptive controller using RBFN(radial basis function network) for robot manipulators The structure of the proposed controller consists of a RBFN and VSC-1 ike control. RBFN is used in order to approximate かon system, and VSC-like control to guarantee robustness On the basis of the Lyapunov stability theorem, we guarantee the stability for the total system. And the learning law of RBFN is established by the Lyapunov method, Finally, we apply the proposed controller to tracking control for a 2 link SCARA type robot manipulator.

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The design method of dead-time compensator for processes with multiplicative uncertainty and long dead time (승산 불확실성을 가지는 시간 지연 시스템의 제어기 설계 방법)

  • 김인희;마진석;최병태;김우현;구본호;권우현
    • 제어로봇시스템학회:학술대회논문집
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    • 2000.10a
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    • pp.237-237
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    • 2000
  • In this paper, The modified dead-time compensator for plants with an integrator and long dead time is proposed. The design procedure takes account of the closed-loop performance and robustness. The tuning of the controller can be done using some information about the plant and its uncertainties. The proposed controller is compared to others recently presented in the literature. Some simulation results verify good closed-performance and robustness of the proposed DTC.

Properties of Adaptive Filter Using Hadamard Transformation (하다마드 변환을 이용한 적응필터의 특성)

  • 이태훈;박진배
    • 제어로봇시스템학회:학술대회논문집
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    • 2000.10a
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    • pp.242-242
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    • 2000
  • Comparing to the conventional adaptive filters using LMS algorithm, the proposed adaptive filters can reduce the amounts of computation and have robustness to variance of characteristics of input signals. LMS algorithm is performed in the domain of Hadamard transform after a reference signal and input signal are transformed by fast Hadamard transformation. As a transformation from time domain to Hadamard transformed domain, the proposed filter not only maintains the performance of estimating an input signal but also greatly reduces the number of multiplication. Moreover, the effect of characteristic changes of input signal is decreased. Computer simulation shows the stability and robustness of the proposed filter.

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Robustness for Pairwise Multiple Comparison Procedures with Trimmed Means under Violated Assumptions : Bonferroni, Shaffer, and Welsch Procedure

  • Kim, Hyun-Chul
    • Communications for Statistical Applications and Methods
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    • v.4 no.3
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    • pp.775-785
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    • 1997
  • Robustness rates for repeated measures pairwise multiple comparison procedures were investigated in a split plot design with one between- and one within-subjects factor using untrimmed and trimmed data. Five factors were manipulated in the study: distribution, sphericity, variance-covariance heteroscedasticity, total sample size, and sample size ratio. The Welsch test (W) and the Welsch test on trimmed data $(W_{RT})$ performed better than the other procedures, but had a liberal tendency. The trimmed difference score Bonferroni Procedure $(B_{DT})$ was a good choice in some conditions.

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Input Noise Immunity of Multilayer Perceptrons

  • Lee, Young-Jik;Oh, Sang-Hoon
    • ETRI Journal
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    • v.16 no.1
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    • pp.35-43
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    • 1994
  • In this paper, the robustness of the artificial neural networks to noise is demonstrated with a multilayer perceptron, and the reason of robustness is due to the statistical orthogonality among hidden nodes and its hierarchical information extraction capability. Also, the misclassification probability of a well-trained multilayer perceptron is derived without any linear approximations when the inputs are contaminated with random noises. The misclassification probability for a noisy pattern is shown to be a function of the input pattern, noise variances, the weight matrices, and the nonlinear transformations. The result is verified with a handwritten digit recognition problem, which shows better result than that using linear approximations.

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Design of Robust Controller of Inverter for Single UPS (단상 UPS용 인버터의 강인제어기 설계)

  • 김제홍;김재식
    • Proceedings of the IEEK Conference
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    • 2001.06e
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    • pp.233-236
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    • 2001
  • In this paper, a robust controller for UPS inverter is designed using CDM (Coefficient Diagram Method) developed by S. Manabe, by which a low order controller guaranteeing the stability and robustness is easily designed. The proposed controller consists of two control loops, the inner current control loop and the outer voltage control loop. The robustness of the proposed controller is verified through the theoretic evolution and its simulation.

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On the Robustness of Watermarking in the Frequency Domain for Still Images

  • Miyazaki, Akio;Ejima, Masataka
    • Proceedings of the IEEK Conference
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    • 2000.07b
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    • pp.861-864
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    • 2000
  • This paper aims to establish fundamentals of measuring and evaluating the performance of water-marking systems. We first present the general model of a watermarking method for still images. Based on this model, we propose a statistical method of measuring the performance and robustness of the watermarking system. Then, the DCT-based watermarking system is analyzed and its performance is evaluated by using the proposed method.

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