• Title/Summary/Keyword: robust analysis

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Robust Stability Condition and Analysis on Steady-State Tracking Errors of Repetitive Control Systems

  • Doh, Tae-Yong;Ryoo, Jung-Rae
    • International Journal of Control, Automation, and Systems
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    • v.6 no.6
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    • pp.960-967
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    • 2008
  • This paper shows that design of a robustly stable repetitive control system is equivalent to that of a feedback control system for an uncertain linear time-invariant system satisfying the well-known robust performance condition. Once a feedback controller is designed to satisfy the robust performance condition, the feedback controller and the repetitive controller using the performance weighting function robustly stabilizes the repetitive control system. It is also shown that we can obtain a steady-state tracking error described in a simple form without time-delay element if the robust stability condition is satisfied for the repetitive control system. Moreover, using this result, a sufficient condition is provided, which ensures that the least upper bound of the steady-state tracking error generated by the repetitive control system is less than or equal to the least upper bound of the steady-state tracking error only by the feedback system.

Research Issues in Robust QFD

  • Kim, Kwang-Jae;Kim, Deok-Hwan
    • Industrial Engineering and Management Systems
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    • v.7 no.2
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    • pp.93-100
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    • 2008
  • Quality function deployment (QFD) provides a specific approach for ensuring quality throughout each stage of the product development and production process. Since the focus of QFD is placed on the early stage of product development, the uncertainty in the input information of QFD is inevitable. If the uncertainty is neglected, the QFD analysis results are likely to be misleading. It is necessary to equip practitioners with a new QFD methodology that can model, analyze, and dampen the effects of the uncertainty and variability in a systematic manner. Robust QFD is an extended version of QFD methodology, which is robust to the uncertainty of the input information and the resulting variability of the QFD output. This paper discusses recent research issues in Robust QFD. The major issues are related with the determination of overall priority, robustness evaluation, robust prioritization, and web-based Robust QFD optimizer. Our recent research results on the issues are presented, and some of future research topics are suggested.

Adaptive Robust Control for Robot Manipulator with the Uncertain Bound Estimation and Implementation (불확실성의 경계를 추정하는 로봇 매니퓰레이터의 적응견실제어기 설계 및 실험)

  • 한명철;하인철
    • Journal of Institute of Control, Robotics and Systems
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    • v.10 no.4
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    • pp.312-316
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    • 2004
  • In this paper, it is presented an adaptive robust control system to implement real-time control of a robot manipulator. There are Quantitative or qualitative differences between a real robot manipulator and a robot modeling. In order to compensate these differences, uncertain factors are added to a robot modeling. The uncertain factors come from imperfect knowledge of system parameters, payload change, friction, external disturbance, etc. Also, uncertainty is often nonlinear and time-varying. In the proceeding work, we proposed a class of robust control of a robot manipulator and provided the stability analysis. In the work, we propose a class of adaptive robust control of robot manipulator with bound estimation. Through experiments, the proposed adaptive robust control scheme is proved to be an efficient control technique for real-time control of a robot system using DSP.

Design of Robust Motion Controllers with Internal-Loop Compensator (내부루프 보상기를 가지는 강인 동작 제어기의 설계)

  • Kim, Bong-Geun;Jeong, Wan-Gyun
    • Transactions of the Korean Society of Mechanical Engineers A
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    • v.25 no.10
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    • pp.1501-1513
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    • 2001
  • Disturbance observer, adaptive robust control, and enhanced internal model control are model based disturbance attenuation methods famous for robust motion controller which can satisfy desired performance and robustness of high-speed/high-accuracy positioning systems. In this paper, these are shown to be the same scheme with different parameterizations. To do this, a generalized framework, called as RIC(robust internal-loop compensator) is proposed and the conventional schemes are analyzed in the RIC framework. Through this analysis, it can be shown that there are inherent similarities between the schemes and advantages of the RIC in the viewpoint of controller design. This is verified through simulations and experiments.

Robust Voltage Controller of Single-Phase Inverter for UPS (무정전전원장치용 단상인버터의 강인한 전압제어기)

  • Ku, Dae-Kwan;Ji, Jun-Keun;Cha, Gueesoo;Moon, Jun-Hee
    • Proceedings of the KIPE Conference
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    • 2010.11a
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    • pp.298-299
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    • 2010
  • In this paper a robust voltage controller of single-phase inverter for UPS is presented. The voltage controller is designed using ${\mu}-based$ robust control scheme to simultaneously guarantee robust stability and robust tracking performance in presence of filter and load parameter variations. Firstly the robust performance of the resulting controller is theoretically confirmed via ${\mu}-analysis$. Then simulation results for single-phase inverter system with linear and nonlinear loads demonstrate feasibility of the proposed control method providing improved performance - good regulation and fast dynamic response.

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STABLE AND ROBUST ℓp-CONSTRAINED COMPRESSIVE SENSING RECOVERY VIA ROBUST WIDTH PROPERTY

  • Yu, Jun;Zhou, Zhiyong
    • Journal of the Korean Mathematical Society
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    • v.56 no.3
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    • pp.689-701
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    • 2019
  • We study the recovery results of ${\ell}_p$-constrained compressive sensing (CS) with $p{\geq}1$ via robust width property and determine conditions on the number of measurements for standard Gaussian matrices under which the property holds with high probability. Our paper extends the existing results in Cahill and Mixon from ${\ell}_2$-constrained CS to ${\ell}_p$-constrained case with $p{\geq}1$ and complements the recovery analysis for robust CS with ${\ell}_p$ loss function.

Robust Stabilization of Uncertain Nonlinear Systems via Fuzzy Modeling and Numerical Optimization Programming

  • Lee Jongbae;Park Chang-Woo;Sung Ha-Gyeong;Lim Joonhong
    • International Journal of Control, Automation, and Systems
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    • v.3 no.2
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    • pp.225-235
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    • 2005
  • This paper presents the robust stability analysis and design methodology of the fuzzy feedback linearization control systems. Uncertainty and disturbances with known bounds are assumed to be included in the Takagi-Sugeno (TS) fuzzy models representing the nonlinear plants. $L_2$ robust stability of the closed system is analyzed by casting the systems into the diagonal norm bounded linear differential inclusions (DNLDI) formulation. Based on the linear matrix inequality (LMI) optimization programming, a numerical method for finding the maximum stable ranges of the fuzzy feedback linearization control gains is also proposed. To verify the effectiveness of the proposed scheme, the robust stability analysis and control design examples are given.

Robust Stability Analysis of an Uncertain Nonlinear Networked Control System Category

  • Fei Minrui;Yi Jun;Hu Huosheng
    • International Journal of Control, Automation, and Systems
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    • v.4 no.2
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    • pp.172-177
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    • 2006
  • In the networked control system (NCS), the uncertain network-induced delay and nonlinear controlled object are the main problems, because they can degrade the performance of the control system and even destabilize it. In this paper, a class of uncertain and nonlinear networked control systems is discussed and its sufficient condition for the robust asymptotic stability is presented. Further, the maximum network-induced delay that insures the system stability is obtained. The Lyapunov and LMI theorems are employed to investigate the problem. The result of an illustrative example shows that the robust stability analysis is sufficient.

The Robust Pattern Recognition System for Flexible Manufacture Automation (유연 생산 자동화를 위한 Robust 패턴인식 시스템)

  • Wi, Young-Ryang;Kim, Mun-Hwa;Jang, Dong-Sik
    • Journal of Korean Institute of Industrial Engineers
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    • v.24 no.2
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    • pp.223-240
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    • 1998
  • The purpose of this paper is to develop the pattern recognition system with a 'Robust' concept to be applicable to flexible manufacture automation in practice. The 'Robust' concept has four meanings as follows. First, pattern recognition is performed invariantly in case the object to be recognized is translated, scaled, and rotated. Second, it must have strong resistance against noise. Third, the completely learned system is adjusted flexibly regardless of new objects being added. Finally, it has to recognize objects fast. To develop the proposed system, contouring, spectral analysis and Fuzzy ART neural network are used in this study. Contouring and spectral analysis are used in preprocessing stage, and Fuzzy ART is used in object classification stage. Fuzzy ART is an unsupervised neural network for solving the stability-plasticity dilemma.

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Robust Design of the Back-plate Shape of the Disc Brake Pad for Reduction of Uneven Wear (디스크 브레이크의 편마모 저감을 위한 브레이크 패드의 백플레이트 형상 강건설계)

  • Park, Jin-Tack;Han, Seung-Wook;Choi, Nak-Sam
    • Transactions of the Korean Society of Automotive Engineers
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    • v.22 no.1
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    • pp.8-19
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    • 2014
  • In this paper, a robust design of the back-plate of the brake pad to decrease the uneven wear of the pad was studied. A finite element analysis was performed to analyze the pressure distributions on the contact surfaces. Optimized back-plate shape of the brake pad was determined using the Taguchi method. The effectiveness of the robust design was clarified by the wear tests with a dynamometer.