• 제목/요약/키워드: Time-varying delay time

검색결과 312건 처리시간 0.025초

가변적인 통신지연시간을 갖는 원격 작업 환경을 위한 실시간 햅틱 렌더링 (Real-Time Haptic Rendering for Tele-operation with Varying Communication Time Delay)

  • 이경노;정성엽
    • 동력기계공학회지
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    • 제13권2호
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    • pp.71-82
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    • 2009
  • This paper presents a real-time haptic rendering method for a realistic force feedback in a remote environment with varying communication time-delay. The remote environment is assumed as a virtual environment based on a computer graphics, for example, on-line shopping mall, internet game and cyber-education. The properties of a virtual object such as stiffness and viscosity are assumed to be unknown because they are changed according to the contact position and/or a penetrated depth into the object. The DARMAX model based output estimator is proposed to trace the correct impedance of the virtual object in real-time. The output estimator is developed on the input-output relationship. It can trace the varying impedance in real-time by virtue of P-matrix resetting algorithm. And the estimator can trace the correct impedance by using a white noise that prevents the biased input-output information. Realistic output forces are generated in real-time, by using the inputs and the estimated impedance, even though the communication time delay and the impedance of the virtual object are unknown and changed. The generated forces trace the analytical forces computed from the virtual model of the remote environment. Performance is demonstrated by experiments with a 1-dof haptic device and a spring-damper-based virtual model.

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Robust H${\infty}$Fuzzy Control of Nonlinear Systems with Time-Varying Delay via Static Output Feedback

  • Kim, Taek-Ryong;Park, Jin-Bae;Joo, Young-Hoon
    • 제어로봇시스템학회:학술대회논문집
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    • 제어로봇시스템학회 2005년도 ICCAS
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    • pp.1486-1491
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    • 2005
  • In this paper, a robust H${\infty}$ stabilization problem to a uncertain fuzzy systems with time-varying delay via static output feedback is investigated. The Takagi-Sugeno (T-S) fuzzy model is employed to represent uncertain nonlinear systems with time-varying delayed state, which is a continuous-time or discrete-time system. Using a single Lyapunov function, the globally asymptotic stability and disturbance attenuation of the closed-loop fuzzy control system are discussed. Sufficient conditions for the existence of robust H${\infty}$controllers are given in terms of linear matrix inequalities.

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시변 지연 이산 시간 비선형 시스템에 대한 정적 출력 궤환 $H\infty$ 퍼지 강인 제어기 설계 (Static Output Feedback Robust $H\infty$ Fuzzy Control of Discrete-Time Nonlinear Systems with Time-Varying Delay)

  • 김택룡;박진배;주영훈
    • 한국지능시스템학회:학술대회논문집
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    • 한국퍼지및지능시스템학회 2005년도 춘계학술대회 학술발표 논문집 제15권 제1호
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    • pp.149-152
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    • 2005
  • In this paper, a robust $H\infty$ stabilization problem to a uncertain discrete-time fuzzy systems with time-varying delay via static output feedback is investigated. The Takagi -Sugeno (T-S) fuzzy model is employed to represent an uncertain nonlinear systems with time-varying delayed state. Using a single Lyapunov function, the globally asymptotic stability and disturbance attenuation of the closed-loop fuzzy control system are discussed. Sufficient conditions for the existence of robust $H\infty$ controllers are given in terms of linear matrix inequalities.

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양자화와 오버플로우 비선형성을 가지는 이산시간 불확실 지연 특이시스템의 지연종속 강인 안정성 (Delay-dependent Robust Stability of Discrete-time Uncertain Delayed Descriptor Systems using Quantization/overflow Nonlinearities)

  • 김종해;오도창
    • 전기학회논문지
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    • 제62권4호
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    • pp.529-535
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    • 2013
  • This paper considers the problem of robust stability for uncertain discrete-time interval time-varying delayed descriptor systems using any combinations of quantization and overflow nonlinearities. First, delay-dependent linear matrix inequality (LMI) condition for discrete-time descriptor systems with time-varying delay and quantization/overflow nonlinearities is presented by proper Lyapunov function. Second, it is shown that the obtained condition can be extended into descriptor systems with uncertainties such as norm-bounded parameter uncertainties and polytopic uncertainties by some useful lemmas. The proposed results can be applied to both descriptor systems and non-descriptor systems. Finally, numerical examples are shown to illustrate the effectiveness and less conservativeness.

시변 지연시간을 가지는 미지의 시스템에 대한 간접 극배치 적응 PID 제어기 (Indirect Adaptive Pole Assignment PID Controllers for Unknown Systems with time varying delay)

  • 남현도;안동준
    • 대한전기학회:학술대회논문집
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    • 대한전기학회 1988년도 전기.전자공학 학술대회 논문집
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    • pp.913-916
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    • 1988
  • Indirect adaptive pole assignment PID controllers for unknown systems with time varying delay, is proposed. Unknown system parameters are estimated by recursive least square method, and time varying delay is estimated using indirect predictors. Since the order of parameter vectors didn't increase, the computational burden is not largely increased in spite of using indirect adaptive control method with time varying delay estimation. Computer simulation is performed to illustrate the efficiency of the proposed method.

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Design of Robust Control for State-Delay Systems

  • Joon, Kwon-Taek;Chul, Ha-In;Chul, Han-Myung
    • 제어로봇시스템학회:학술대회논문집
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    • 제어로봇시스템학회 2001년도 ICCAS
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    • pp.129.6-129
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    • 2001
  • In this paper, we consider a class of time-varying systems with time-varying state delay. Generally, this system is affected by many uncertainties and we assume that the information of the upper bound(time-delay, uncertainty) is known. In this work, we propose a robust control for system with state delay. The stability based on Lyapunov function is presented. Finally, a numberical example is given to demonstrate the validity of the result.

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오차피드백 제어입력이 개선된 모델추종 시간지연제어기 설계 (A Design of Model-Following Time Delay Controller with Modified Error Feedback Controller)

  • 박병석;윤지섭;강이석
    • 한국정밀공학회지
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    • 제17권12호
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    • pp.176-184
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    • 2000
  • TDC(Time Delay Control) deals with the time-varying system parameters, unknown dynamics and unexpected disturbances using time delay. TDC can be divided into two separate parts: an auxiliary controller and a servo controller. The two controllers can be designed independently. The auxiliary controller is used to reduce sensitivity to parameter variations, nonlinear effects, and other disturbances. The servo controller is to reduce the error between the desired command and output. We propose the model-following time delay controller with modified error feedback controller. This was applied to follow the desired reference model for the uncertain time-varying overhead crane. The model generates the damped-out swinging motion trajectory to suppress the swinging motion caused by the acceleration and the deceleration of crane transportation. The control performance was evaluated through simulations. The theoretical results indicate that this control method shows excellent performance to an overhead crane with the uncertain time-varying parameters.

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Recursive Least Squares Run-to-Run Control with Time-Varying Metrology Delays

  • Fan, Shu-Kai;Chang, Yuan-Jung
    • Industrial Engineering and Management Systems
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    • 제9권3호
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    • pp.262-274
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    • 2010
  • This article investigates how to adaptively predict the time-varying metrology delay that could realistically occur in the semiconductor manufacturing practice. Metrology delays pose a great challenge for the existing run-to-run (R2R) controllers, driving the process output significantly away from target if not adequately predicted. First, the expected asymptotic double exponentially weighted moving average (DEWMA) control output, by using the EWMA and recursive least squares (RLS) prediction methods, is derived. It has been found that the relationships between the expected control output and target in both estimation methods are parallel, and six cases are addressed. Within the context of time-varying metrology delay, this paper presents a modified recursive least squares-linear trend (RLS-LT) controller, in combination with runs test. Simulated single input-single output (SISO) R2R processes subject to various time-varying metrology delay scenarios are used as a testbed to evaluate the proposed algorithms. The simulation results indicate that the modified RLS-LT controller can yield the process output more accurately on target with smaller mean squared error (MSE) than the original RLSLT controller that only deals with constant metrology delays.

시간지연 특이시스템의 비약성 보장비용 제어 (Non-fragile guaranteed cost control of delayed descriptor systems)

  • 김종해
    • 대한전기학회:학술대회논문집
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    • 대한전기학회 2006년도 심포지엄 논문집 정보 및 제어부문
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    • pp.246-248
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    • 2006
  • This paper is concerned with non-fragile guaranteed cost state feedback controller design algorithm for descriptor systems with time-varying delay and static state feedback controller with multiplicative uncertainty. The considered uncertainties are norm-bounded and time delay is time-varying. Under the condition of controller gain variations, conditions for the existence of controller satisfying asymptotic stability and non-fragility and controller design method are derived via LMI approach. Moreover, the measure of non-fragility and the upper bound to minimize guaranteed cost function are given.

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WT 평면에서의 두 신호 시지연 추정 (Time Delay Estimation of Two Signals in Wavelet Transform Domain)

  • 김재국;이영석;김성환
    • 한국음향학회지
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    • 제16권4호
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    • pp.5-10
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    • 1997
  • 본 논문에서는 웨이브렛 변환을 이용한 새로운 시지연 추정방법인 WTD-LMSTDE을 제안하였다. 이 방법은 시평면에서 입력 신호 자기상관 행렬의 고유치 분포를 줄임으로서 수렴속도를 향상시켰다. 이 알고리즘의 성능을 시불변과 시변인 경우에 대해서 평가하였다. 결과로서 시불변 시지연의 경우에, WTD-LMSTDE의 추정 정확도가 LMSTDE보다 SNR에 따라서 3.3%에서 12.5%까지 개선되었다. 시변 시지연의 경우에는, 선형적으로 증가하는 자연 환경에서 WTD-LMSTDE의 평균 오차 전력이 잡음이 없는 상태에서 LMSTDE와 비교하여 2.4dB정도 감소하였다. 결론적으로 WTD-LMSTDE의 성능이 LMSTDE보다 우수함을 확인할 수 있었다.

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