• Title/Summary/Keyword: Robust algorithm

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The design of the variable structure position controller for a DC servo motor using Digital Signal Processor (DSP를 이용한 DC 모타에 대한 가변구조 위치제어기 설계)

  • Park, Gwi-Tae;Kang, Moon-Ho;Lee, Young;Moon, Ii-Nam;Yoo, Ji-Yoon
    • Proceedings of the KIEE Conference
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    • 1990.07a
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    • pp.319-323
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    • 1990
  • VSS controller is suited for systems where the robust performances in the presence of parameter variations and disturbances are most important. The practical realization of such robust VSS algorithm using DSP ($TMS_{32020}$) is dicussed in this paper. PWH-like control signal which is produced by directly using VSS control algorithm substitutes the PWM amplifier. And the armature current is used in construction of switching function for the purpose of increasing switching frequency. In order to compensate steady state error produced by various external disturbances practical integral compensator is considered.

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A Study on the Design of Adaptive Controller with Supervision Function (감독기능을 갖는 적응제어기 구성에 관한 연구)

  • 이창구;권오형;황형수;김성중
    • The Transactions of the Korean Institute of Electrical Engineers
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    • v.37 no.12
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    • pp.894-902
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    • 1988
  • In this paper, a method for the design of robust adaptive controller using the heuristic rules of industrial engineers is presented. This scheme works on the basis of heuristic rules and includes a supervisor, a system identifier and a detuner. The supervisor detects onsetting instability based on the analysis of the amplitude and the trend of error signal, also selects running controllers. Upon detecting instability, the controller is switched to a PID algorithm and run recursively until stability is restored. Simultaneously, new input / output data is gathered and the system identifier runs to get critical sensitivity (kc) and critical period(tc). Based on the new values(kc, tc), a GPC controller is redesigned and normal GPC is finally run. The algorithm described in this paper belongs to the supervised adaptive control category with a limited use of heuristic rules. Finally, we show the robust of this scheme by simulated example.

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A Navigation Control Algorithm for Automated Guided Vehicle Based on Neural Network Sensing Prediction (신경망 예측에 기반한 AGV의 주행 알고리듬)

  • 나용균;김선효;오세영;성학경;김성권
    • 제어로봇시스템학회:학술대회논문집
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    • 2000.10a
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    • pp.428-428
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    • 2000
  • A robust intelligent algorithm for AGV navigation control is presented here based on both magnetic and gyro sensors to track a reference trajectory. Since the proposed system uses an intermittent array of short magnetic tape strips, it lends itself to a very easy installation and maintenance compared to other types of positioning references such as electric wire, magnets, RF and laser beacons. The neural network is to predict the lateral deviation of the AGV in the intervals where no magnetic tape references are available. Further, the use of intelligent control ensures a robust and flexible control performance. Computer simulation of AGV control demonstrates its adequate tracking performances even where the sensor information is not available. Real experiments using Samsung AGV are also on the way for real verification

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$\mu$-Controller Design using Genetic Algorithm (유전알고리즘을 이용한 $\mu$제어기 설계)

  • 기용상;안병하
    • Proceedings of the Korean Society of Precision Engineering Conference
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    • 1996.11a
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    • pp.301-305
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    • 1996
  • $\mu$ theory can handle the parametric uncertainty and produces more non-conservative controller than H$_{\infty}$ control theory. However an existing solution of the theory, D-K iteration, creates a controller of huge order and cannot handle the real or mixed real-complex perturbation sets. In this paper, we use genetic algorithms to solve these problems of the D-K iteration method. The Youla parameterization is used to obtain all stabilizing controllers and the genetic algorithms determines the values of the state feedback gain, the observer gain, and Q parameter to minimize $\mu$, the structured singular value, of given system. From an example, we show that this method produces lower order controller which controls a real parameter-perturbed plant than D-K iteration method.

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A Study on the Robust Direct Adaptive Controller Design in the presence of Unmodelled Dynamics and Disturbances (비모형화 특성과 외란을 고려한 강인한 직접 적응제어기 설계에 관한 연구)

  • Park, Kwan-Jong;Kim, Eung-Seok;Kim, Hong-Pil;Yang, Hai-Won
    • Proceedings of the KIEE Conference
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    • 1990.07a
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    • pp.77-80
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    • 1990
  • This paper presents a continuous-time robust direct adaptive algorithm in the presence of bounded disturbances and / or unmodeled dynamics. In the new algorithm, Narendra's adaptation law is adapted. And a term, proportional to the product of tracking error and normalizing signal, is added to the conventional control law. It is shown that the performance of the adaptive schemes is improved if a proportional adaptation tera is added to the control law. The scalar case is only discussed in the stability analysis. Computer simulation is presented to complement the theoretical result.

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Design of a Controller for Enhancing Positioning Performance of a PZT Driven Stage (PZT 구동 스테이지의 위치 제어 성능 향상을 위한 제어기 설계)

  • Park, J.S.;Jeong, Kyu-Won
    • Journal of the Korean Society of Manufacturing Technology Engineers
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    • v.21 no.3
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    • pp.465-472
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    • 2012
  • This paper describes a new robust control algorithm which can be used to enhance the positioning performance of an ultra-precision positioning system. The working table is supported by flexure hinges and moved by a piezoelectric actuator, whose position is measured by an ultra-precise linear encoder. The system dynamics is very complicated because the movement of the table is governed by both the mechanical characteristics and those of the PZT actuator. So that, the dynamics of the stage was modeled roughly in this paper, and the overall system was formularized to solve the small gain problem. A series of experiments was conducted in order to verify the usefulness of the proposed algorithm. From the experimental results, the positioning performance such as the accuracy, the rise time and the hysteresis nonlinearity were greatly improved.

A Study on Optimal Design of $H_{\infty}$-PSS using IA (IA를 이용한 $H_{\infty}$-PSS의 최적 설계에 관한 연구)

  • Lee, Jong-Phil;Hur, Dong-Ryol;Kim, Chang-Hyun;Chung, Hyeng-Hwan
    • Proceedings of the KIEE Conference
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    • 2001.07a
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    • pp.125-127
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    • 2001
  • In this paper, a robust $H_{\infty}$ optimal design problem under a structure-specified PSS is investigated for power systems with parameter variation and disturbance uncertainties. Immune algorithm is employed for optimization method of PSS parameter. It is shown that the proposed $H_{\infty}$-PSS tuned using immune algorithm is more robust than conventional PSS.

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Adaptive Watermarking based on Fuzzy Inference and Human Visual System (퍼지 추론과 시각특성 기반의 적응적 워터마킹)

  • Shin Hee-Jong;Park Ki-Hong;Kim Yoon-Ho
    • Journal of Digital Contents Society
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    • v.5 no.4
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    • pp.311-315
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    • 2004
  • In this paper, we proposed a robust watermarking algorithm based on fuzzy inference and human visual system. In the first, discrete wavelet transform(DWT) is involved to calculate additive energy strength, then we devised fuzzy inference, which was established by computing contrast and texture degree in gray-level image. Watermark is embeded into the coefficients of 3-level DWT so as to consider a spatial effects. Visual recognizable patterns such as binary image were used as a watermark Consequently, experimental results showed that proposed algorithm is robust in JPEC compression.

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Endpoint Detection of Speech Signal Using Wavelet Transform (웨이브렛 변환을 이용한 음성신호의 끝점검출)

  • 석종원;배건성
    • The Journal of the Acoustical Society of Korea
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    • v.18 no.6
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    • pp.57-64
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    • 1999
  • In this paper, we investigated the robust endpoint detection algorithm in noisy environment. A new feature parameter based on a discrete wavelet transform is proposed for word boundary detection of isolated utterances. The sum of standard deviation of wavelet coefficients in the third coarse and weighted first detailed scale is defined as a new feature parameter for endpoint detection. We then developed a new and robust endpoint detection algorithm using the feature found in the wavelet domain. For the performance evaluation, we evaluated the detection accuracy and the average recognition error rate due to endpoint detection in an HMM-based recognition system across several signal-to-noise ratios and noise conditions.

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A Study on the Image Watermarking Method (이미지 워터마킹 기법에 관한 연구)

  • Lee, Doo Sung;Kim, Sun Hyung;Kim, Ki Seok
    • Journal of Korea Society of Digital Industry and Information Management
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    • v.5 no.4
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    • pp.161-168
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    • 2009
  • There are many research for efficient, robust and invisible watermarking system that protects the digital contents like a image and animation according to growth of IT industry. First of all, frequency domain watermarking system like DWT(Descrete Wavelet Transform) is excellent because of minimum loss of original image and robustness of external attack. But, if we raise the insertion strength of watermark, then blazing of image occurs on existing DWT watermarking system and we should have a regular square image. In this study, we research the overflow check for preventing image from blazing and a robust and invisible watermarking algorithm. And we research a free-size DWT watermarking system using padding bytes, without a dependency of size.