• 제어로봇시스템학회:학술대회논문집
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• 1996.10b
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• pp.1197-1200
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• 1996

This paper is concerned with the design of robust state feedback controller for a class of linear time-delay systems with norm-bounded nonlinear uncertainties. Under the proposed delay-independent criterion, asymptotic stability for the system is investigated using the conventional Lyapunov method. Moreover, the robust controller can be obtained by solving the linear matrix inequality which is equivalent to the suggested conditions.

• 제어로봇시스템학회:학술대회논문집
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• 1996.10b
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• pp.335-338
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• 1996

In this paper, we are going to design an iterative learning controller with the robust properties for initial error. For this purpose, the PID-type learning law will be considered and the design guide-line will be presented for the selection of the learning gain. Also, we are going to suggest a condition for the convergence of control input for a plant with input delay. Several simulation results are presented, which shows the effectiveness of the proposed algorithms.

• Proceedings of the IEEK Conference
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• 1998.06a
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• pp.215-218
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• 1998

In this paper, we design the $H_{\infty}$ controllers satisfying robust stability and performance for underwater vehicle. The underwater vehicle has computations delay time and input delay. In addition, there exist parameter uncertainties by the roll motion coefficient error, buoyance error, and gravity error. We design the $H_{\infty}$ controllers using model-matching method and check the performance of the proposed controller by nonlinear simulation which includes time delay model, sensor error model, and actuator model.

• Journal of Institute of Control, Robotics and Systems
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• v.18 no.6
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• pp.509-512
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• 2012

This paper presents the state feedback control design for discrete time nonlinear systems where there exists a time delay in input. It is shown that under some boundedness condition, the time delay nonlinear systems can be transformed into the time delay linear systems with time varying parameters. Sufficient conditions for existence of stabilizing state feedback controller are characterized by linear matrix inequalities. Finally, an illustrative example is given in order to show the effectiveness of our design method.

• The Transactions of The Korean Institute of Electrical Engineers
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• v.57 no.10
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• pp.1854-1860
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• 2008

In this paper, we deal with the problem of delay-dependent robust and non-fragile stabilization for descriptor systems with parameter uncertainties and time-varying delays on the basis of strict LMI(linear matrix inequality) technique. Also, the considering controller is composed of multiplicative uncertainty. The delay-dependent robust and non-fragile stability criterion without semi-definite condition and decomposition of system matrices is obtained. Based on the criterion, the problem is solved via state feedback controller, which guarantees that the resultant closed-loop system is regular, impulse free and stable in spite of all admissible parameter uncertainties, time-varying delays, and controller fragility. Numerical examples are presented to demonstrate the effectiveness of the proposed method.

• Proceedings of the KIEE Conference
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• 2006.07d
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• pp.1840-1841
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• 2006

Plants with long time-delays can not be often controlled effectively using a simple PID controller. The main reason for this is that the additional phase lag contributed by the time-delay tends to destabilize the closed-loop system. The stability problem can be solved by smith predictor. However, in this case responses are very sensitive to the estimated model errors. To reduce sensitive problem, this paper is presented based on virtual reference feedback tuning of the time delay plant using the closed-loop test to find parameters for a PID controller using the closed-loop test data.

• 제어로봇시스템학회:학술대회논문집
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• 1997.10a
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• pp.69-72
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• 1997

A universal controller is designed using a DSP (digital signal processor). The design objectives of the system are to implement control algorithms that require a lot of calculations and to develop a convenient user-interface environment. To demonstrate the efficiency of the system, the time delay control algorithm is implemented for the 2 D.O.F.SCARA type robot and the experimental results are presented.

• Proceedings of the IEEK Conference
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• 1999.06a
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• pp.94-97
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• 1999

In this paper, a new real-time neural network connection admission controller is proposed. The proposed controller measures traffic flows, cell loss rate and cell delay periodically each classes. The Neural network learns the relation between those measured information and service quality by real-time. Also the proposed controller uses the DWRR multiplexer with buffer dedicated to every traffic source in order to measure the delay that cells experience in buffer. Experimental result shows that the proposed method can control effectively heterogeneous traffic sources with diverse QoS requirement.

• Journal of the Institute of Electronics Engineers of Korea SC
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• v.45 no.6
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• pp.102-107
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• 2008

We propose an autotuning algorithm for PI controller with unknown plant. The proposed algorithm uses a saturation function and time delay element as a test signal. Since the integral element of PI controller reduces a phase margin in the closed loop system, the closed loop system could be resulted in unstable with PI controller. To avoid unstable in the closed loop system with PI controller, the proposed algorithm identifies one point information in the 3rd quadrant of Nyquist plot with a time delay element. The proposed method improves an accuracy of one point identified information with one saturation function. We demonstrate a performance of the proposed method via a simulation.

• The Journal of the Acoustical Society of Korea
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• v.9 no.6
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• pp.53-61
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• 1990

Real-time implementations of the active adaptive noise controller are proposed and tested. There are three problems in active noise control such as real-time processing, an acoustic feedback of secondary signal and a time-delay of control system elements. For real-time processing, the DSP56001 was used. To avoid acoustic feedback, the secondary signal was excluded from prediction. And for compensation of time delay, the ahead prediction was applied. As the primary noise is reflected in space, the reflected noise should be controlled for perfect noise control. But in this case, the controller might be unstable. For solving the problem, it is proposed that the source noise and the reflected noise are predicted separately. Some experimental results show the stability and effectiveness of the proposed controller.