• Proceedings of the Computational Structural Engineering Institute Conference
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• 1995.10a
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• pp.242-249
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• 1995

In order to search more efficient structural control algorithm, several closed-loop algorithm are developed. Among those, feedback control algorithm using parameters as displacement velocity, and acceleration has been studied. In this paper, especially the characteristics of accleration feedback is studied as more efficient control algorithm than any others. Furthermore the fact that ATMD with acceleration feedback system further reduce the variance of structural displacement rather than with displacement or velocity feedback system will be examined and proved.

• Journal of Advanced Marine Engineering and Technology
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• v.31 no.6
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• pp.791-796
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• 2007

When 2 sets of PID controllers are coupled directly each other to configure a closed control loop on behalf of coupling a controller and a plant. the behaviors or this exclusive loop system are expected to be unique in inherent system responses. If its properties be disclosed and generalized well in advance, it is possible for us to use the results for the purpose of fault detection and performance monitoring between control stations from the stage of system design. particularly in such cases as cascade control systems. In this paper. general properties of the proposed system are analyzed firstly to check whether it is controllable and how its steady responses would be. To simplify calculation, the analysis has been performed based on the transfer equation derived from a modelled case which consists of 2 PI controllers and signal converters between them. including time delay element and first-lag element to consider the situation of signal transmission. The results acquired from simulation are suggested to show how it works actually.

• Journal of the Korean Institute of Telematics and Electronics
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• v.23 no.6
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• pp.888-894
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• 1986

In this paper, a phase locked loop control system is designed to have high performance and stability in a 2-phase bifilar winding PM step motor. The BODE diagram analysis method is used to improve the stability and dynamic characteristic of the closed loop control system. Also, a PLL servo is used to accomplish high-precision speed and to attain smooth ness. In applying the PLL control to the step motor, a new design method is suggested to solve the control problem which occurs as a result of the limited maximum acceleration of the step motor. A simple design method is suggested without using the complicated multi-step characteirstic of the step motor in constant voltage driving. Computer simulation results agree clorelg with experiments, indicating that the PLL servo system of the step motor designed is very useful.

• 제어로봇시스템학회:학술대회논문집
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• 2000.10a
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• pp.49-49
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• 2000

Sensors are used to measure the states in need for control in a closed-loop system. Accuracy, reliability, stability of sensors are closely related to the controller performance. In case of sensor faults, they are detected by examining the sensor output values and the major values of the system. And then the types of the faults are recognized by the analysis of symptoms of faults. In this paper, a self-validating sensor is applied to the control of an aerodynamic plant system with the sensor fault problems in the potentiometer module for exact positioning to show the applicability. We propose a digital controller can provide a satisfactory loop performance even when the sensor faults occur.

• 제어로봇시스템학회:학술대회논문집
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• 1987.10a
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• pp.759-764
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• 1987

The design and application of optimal control technique to the rotary shearing system is mentioned in this paper. To maximize the accuracy in both shearing length and blade speed at shearing, time-varying gain patterns for closed loop control are designed on the basis of fixed terminal time constrained optimal regulator. The performance accuracy in real application has greatly improved than the conventional way of shearing control.

• 제어로봇시스템학회:학술대회논문집
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• 1989.10a
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• pp.489-493
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• 1989

In this paper a new approach to adaptive control using a combination of both direct and indirect methods has been proposed. Based on the estimates of the plant parameters and the current values of the control parameters, closed-loop estimation errors .epsilon.$_{\theta}$(t) and .epsilon.$_{k}$(t) are defined. These in turn are used in the adaptive laws for updating both identification as well as control parameters. The global uniform stability of the overall system is shown by constructing a Lyapunov function.n.

• 제어로봇시스템학회:학술대회논문집
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• 1990.10a
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• pp.463-468
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• 1990

A VSC law is derived for the attitude control of an orbiting spacecraft in the presence of disturbance and parameters variation using reaction jets. The switching surface was chosen to be a linear function of tracking error, its derivative and integral. Simulation results are presented to show that in the closed-loop system, precise attitude control is accomplished in spite of uncertainty in the system.

• Proceedings of the KIEE Conference
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• 1991.07a
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• pp.666-669
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• 1991

This paper deals with the robustness of a direct adaptive pole-placement control algorithm for continuous time plants with unmodeled dynamics. In this paper, least squares method is used for controller parameter adaptation and covariance matrix update equation is modified by normalizing signal to guarantee the boundedness of all signals in the closed loop system. In the proposed algorithm, no a priori knowledge is required and it is shown that persistence of excitation condition is required to ensure the stability of the closed loop system.

• Proceedings of the KIEE Conference
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• 2003.04a
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• pp.186-189
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• 2003

This paper presents an optimal tuning method of the decentralized PI controller of two-input, two-output(TITO) second order system to be formulated as LQR. The tuning method of proposed decentralized PI controller is developed by establishing the relationships between the closed-loop state equation including decentralized PI control factors and the closed-loop state equation of LQR, which can be guaranteed the performance and stability-robustness by selecting the weighting factors Q and R of the cost function in order to satisfy design specifications in frequency domain.

• Proceedings of the KIEE Conference
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• 1993.07a
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• pp.323-325
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• 1993

In this paper, an output feedback controller is proposed for continuous time-invariant linear systems. The proposed controller, LQ-FIR consists of an LQ control gain and an optimal FIR filter. The LQ-FIR controller is derived, and the stability of the closed loop system is proved. The bounds of parameter variations guaranteeing the closed loop stability are obtained, when the LQ-FIR controller is applied to the system with model uncertainties.