• Title/Summary/Keyword: stability control method

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Reference Model Feedback Control and Stability Evaluation for Control System with Hard Non-linearities (견비선형을 갖는 제어시스템에 대한 기준모델 피드백제어 및 안정성평가)

  • Jung, Yu-Chul;Lee, Gun-Bok
    • Transactions of the Korean Society of Machine Tool Engineers
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    • v.15 no.5
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    • pp.72-78
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    • 2006
  • The paper proposes reference model error feedback control scheme for motion control system with hard non-linear components as like saturation and dead-zone in plant input part. Additionally, the plant has the system uncertainty effected by plant model parameter deviation and disturbance. The control algorithm uses the reference model to apply additional feedback loop with the error between reference model output and actual output effected by disturbance and non-linear components. And the stability evaluation based on Popov stability and controller design method are formulated to be performed. The effectiveness of the proposed scheme is examined by simulations. The results are proven by reasonable performances following reference model responses with good disturbance rejection performance without over-tuning of controller.

Sampled Fuzzy Controller for discrete networked control systems (샘플치 퍼지 제어기를 이용한 이산 퍼지 시스템 제어)

  • Kook, Song-Min;Bae, Park-Jin;Kim, Jong-Seon;Hoon, Joo-Young
    • Proceedings of the KIEE Conference
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    • 2008.07a
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    • pp.1783-1784
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    • 2008
  • This paper presents a novel control technique to deal with networked control systems with neutral timedelay, which is known to highly degrade the control performance of the controlled system. The stability analysis and design method for a sampled-data fuzzy controller for discrete networked control systems (NCS). The neutral time-delay and sampling activity will complicate the NCS. And it make the stability analysis much more difficult than that for a continuous-time NCS. Based on the fuzzy control approach, linear matrix inequality (LMI)-based stability conditions are derived to guarantee the neutral T-S fuzzy system stability. The simulation results and practical experiments illustrate that the proposed controller design is realistic.

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Study on Improving Stability of 6×6 Skid-Steering Vehicle by Employing Skyhook Control Method (스카이 훅 제어를 이용한 6×6 견마 차량의 주행 안정성 향상 방안 연구)

  • Jeon, Su-Hee;Lee, Jeong-Han;Yoo, Wan-Suk;Kim, Jae-Yong
    • Transactions of the Korean Society of Mechanical Engineers A
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    • v.35 no.8
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    • pp.905-912
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    • 2011
  • In order to protect equipment such as controllers, it is important to improve the driving stability of $6{\times}6$ skidsteering vehicles driven on rough roads. The estimation and improvement of the driving stability should be based on the vertical acceleration, roll acceleration, and pitch acceleration. These variables will be used to achieve multivariable control and increase the vehicle driving stability. In this study, to improve vehicle stability by reducing the vertical acceleration, roll angular acceleration, and pitch angular acceleration, the skyhook control method is employed to control MR(Magnetorheological) dampers equipped with the vehicle. The proposed control system is tested in multibody dynamic simulation.

An Analytical Solution for Voltage Stability Studies Incorporating Wind Power

  • Lin, Yu-Zhang;Shi, Li-Bao;Yao, Liang-Zhong;Ni, Yi-Xin;Qin, Shi-Yao;Wang, Rui-Ming;Zhang, Jin-Ping
    • Journal of Electrical Engineering and Technology
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    • v.10 no.3
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    • pp.865-876
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    • 2015
  • Voltage stability is one of the most critical security issues which has not yet been well resolved to date. In this paper, an analytical method called PQ plane analysis with consideration of the reactive power capability of wind turbine generator and the wake effect of wind farm is proposed for voltage stability study. Two voltage stability indices based on the proposed PQ plane analysis method incorporating the uncertainties of load-increasing direction and wind generation are designed and implemented. Cases studies are conducted to investigate the impacts of wind power incorporation with different control modes. Simulation results demonstrate that the constant voltage control based on reactive power capability significantly enhances voltage stability in comparison of the conventional constant power factor control. Some meaningful conclusions are obtained.

Terminal Sliding Mode Control of Nonlinear Systems Using Self-Recurrent Wavelet Neural Network (자기 회귀 웨이블릿 신경망을 이용한 비선형 시스템의 터미널 슬라이딩 모드 제어)

  • Lee, Sin-Ho;Choi, Yoon-Ho;Park, Jin-Bae
    • Journal of Institute of Control, Robotics and Systems
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    • v.13 no.11
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    • pp.1033-1039
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    • 2007
  • In this paper, we design a terminal sliding mode controller based on self-recurrent wavelet neural network (SRWNN) for the second-order nonlinear systems with model uncertainties. The terminal sliding mode control (TSMC) method can drive the tracking errors to zero within finite time in comparison with the classical sliding mode control (CSMC) method. In addition, the TSMC method has advantages such as the improved performance, robustness, reliability and precision. We employ the SRWNN to approximate model uncertainties. The weights of SRWNN are trained by adaptation laws induced from Lyapunov stability theorem. Finally, we carry out simulations for Duffing system and the wing rock phenomena to illustrate the effectiveness of the proposed control scheme.

Composite adaptive neural network controller for nonlinear systems (비선형 시스템제어를 위한 복합적응 신경회로망)

  • 김효규;오세영;김성권
    • 제어로봇시스템학회:학술대회논문집
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    • 1993.10a
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    • pp.14-19
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    • 1993
  • In this paper, we proposed an indirect learning and direct adaptive control schemes using neural networks, i.e., composite adaptive neural control, for a class of continuous nonlinear systems. With the indirect learning method, the neural network learns the nonlinear basis of the system inverse dynamics by a modified backpropagation learning rule. The basis spans the local vector space of inverse dynamics with the direct adaptation method when the indirect learning result is within a prescribed error tolerance, as such this method is closely related to the adaptive control methods. Also hash addressing technique, similar to the CMAC functional architecture, is introduced for partitioning network hidden nodes according to the system states, so global neuro control properties can be organized by the local ones. For uniform stability, the sliding mode control is introduced when the neural network has not sufficiently learned the system dynamics. With proper assumptions on the controlled system, global stability and tracking error convergence proof can be given. The performance of the proposed control scheme is demonstrated with the simulation results of a nonlinear system.

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A Stability Estimation Method of HVDC System Using Reduced Model (축약모델을 이용한 HVDC시스템의 안정도 평가)

  • Kim Chan-Ki;Lim Seong-Joo;Choo Jin-Boo
    • The Transactions of the Korean Institute of Power Electronics
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    • v.10 no.1
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    • pp.1-12
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    • 2005
  • This paper deals with the HVDC stability according to controller types and control modes. From the viewpoint of controllers, the HVDC system which has PI, PD and PID, is designed considering the system response and stability. Also the HVDC system consists of multi-control modes like voltage control, current control and alpha control. Therefore, the HVDC stability analysis have to consider the above control modes and controller types. In this paper, the reduced model of HVDC control is analyzed in PSS/E(Power System Simulation/Engineering) and PSCAD/EMTDC.

Parameter Tuning Algorithm for Sliding Mode Control (슬라이딩 모드 제어를 위한 인자 튜닝 알고리듬)

  • 류세희;박장현
    • Proceedings of the Korean Society of Precision Engineering Conference
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    • 2003.06a
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    • pp.438-442
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    • 2003
  • For an efficient sliding mode control system stability and chattering avoidance should be guaranteed. A continuation method using boundary layer is well known as one solution for this. However since not only model uncertainties and disturbances but also control task itself is variable. it is practically impossible to set controller parameters - control discontinuity, control bandwidth, boundary layer thickness - in advance. In this paper first an adaptation law of control discontinuity is introduced to assure system stability and then fuzzy logic based tuning algorithm of design parameters is applied based on monitored performance indices of tracking error, control chattering, and model precision. In the end maximum control bandwidth not exciting unmodeled dynamics and minimum control discontinuity, boundary layer thickness making system stable and free of chattering are found respectively. This eliminates control chattering and enhances control accuracy as much as possible under given control situation. In order to demonstrate the validity of the proposed algorithm safe headway maintenance control for autonomous transportation system is simulated. The control results show that the proposed algorithm guarantees system stability all the time and tunes control parameters consistently and in consequence implements an efficient control in terms of both accuracy and actuator chattering.

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Stability of Time Delay Systems Using Numerical Computation of Argument Principles

  • Suh, Young-Soo
    • International Journal of Control, Automation, and Systems
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    • v.1 no.1
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    • pp.127-133
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    • 2003
  • This paper proposes a new numerical method to check the stability of a general class of time delay systems. The proposed method checks whether there are characteristic roots whose real values are nonnegative through two steps. Firstly, rectangular bounds of characteristic roots whose real values are nonnegative are computed. Secondly, the existence of roots inside the bounds are checked using the numerical computation of argument principles. An adaptive discretization is proposed for the numerical computation of argument principles.

쿨롱마찰을 갖는 유연 링크 로봇의 H$_2$ /H$_\infty$ 최적제어

  • 한성익;김종식
    • Proceedings of the Korean Society of Precision Engineering Conference
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    • 1996.11a
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    • pp.401-405
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    • 1996
  • A new method of nonlinear robust controller synthesis is introduced which is an extension of linear mixed $H_2/H_{\infty}$ control. This method guarantees robust stability fur hard nonlinearity and uncertainty of the plant. The method is applied to the control of a flexible link of robot with Coulomb friction. Simulation shows good performances with respect to the response and the robustness.

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