• Proceedings of the KIEE Conference
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• 2004.11c
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• pp.705-707
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• 2004

In this paper, we propose a robust control technique against parameter uncertainties as well as external disturbances. It is robust control scheme using discrete-time state space disturbance observer. It does not require disturbance modeling, plant inverse modeling and/or Q filter. In frequency domain, its performance is evaluated in terms of sensitivity and complementary sensitivity as well as gain and phase margin. Finally we discuss design criterion of state space disturbance observer considering its performance in frequency domain.

• Proceedings of the Korean Society of Precision Engineering Conference
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• 2001.10a
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• pp.164-168
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• 2001

In this paper, we introduce a new sliding surface adaptable to arbitrary initial conditions. The surface is initially designed to pass given intial errors and subsequently moves towards a predetermined surface via rotating or/and shifting. We call it as a moving sliding surface (MSS) comparing with the conventional ones, for instances, employed by Slotine and Sastry. Using the MSS, it is shown that the tracking is much faster than conventional one without increasing the magnitude of discontinuous control gain. To demonstrate some advantages of the proposed method, we apply the MSS to the path tracking control of a two-degree-of-freedom robotic manipulator subjected to external disturbances.

• Proceedings of the Korean Society of Tribologists and Lubrication Engineers Conference
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• 1998.04a
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• pp.335-341
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• 1998

In this study, the dynamic characteritics in various loading methods for wear tester were investigated experimentally. As for the dead-weight, the pneumatic, and the hydraulic method, the load control performance against external disturbances was estimated under the several loading conditions like the different sliding speed, the varied normal load, and the misaligument. The hydraulic loading method showed the most stable loading performance of all the loading methods in the experiment.

• 제어로봇시스템학회:학술대회논문집
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• 2001.10a
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• pp.113.5-113
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• 2001

In this work, we consider the flexible manipulator system. Generally, the manipulator system may often be made on the base of the imperfect modeling, joint friction, payload change, and external disturbances. These elements are uncertain factors. These uncertainties and flexibility make difficult to control the system. To overcome these defects, a class of robust control law is proposed for the flexible manipulator system and the singular perturbation approach is applied. To show the effectiveness of this control law, simulation is presented for one degree of freedom flexible joint and flexible link system.

• 제어로봇시스템학회:학술대회논문집
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• 1989.10a
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• pp.395-398
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• 1989

A two dimensional pseudo-homogeneous model for the methanol reforming reaction was developed and its steady and dynamic states were studied by a computer simulation. The reactor tube diameter, the catalyst density in the fixed bed, the feed flow rate, the feed temperature and the external temperature were chosen to be adjusted to determine the length of the reactor. The dynamics of the reactor showed that the system was highly nonlinear and sensitive to the feed disturbances.

• 제어로봇시스템학회:학술대회논문집
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• 1992.10b
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• pp.140-145
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• 1992

This paper presents a decentralized model reference adaptive control scheme for an interconnected linear system composed of a number of single-input single-output subsystems in which outgoing interactions pass through the measurement channel and are subjected to bounded external disturbances. The scheme can treat the unknown strength of interactions as well as uncertainties in subsystem dynamics, and allows for the case when the relative degree of each decoupled subsystem does not exceed two.

• 제어로봇시스템학회:학술대회논문집
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• 1995.10a
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• pp.267-270
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• 1995

In this paper, a variable structure control scheme with a terminal sliding mode is proposed for robot manipulators. The proposed control scheme guarantees that the output tracking error converges to zero in finite time, and the overall system shows robust property against parametric uncertainties and external disturbances all the time.

• 제어로봇시스템학회:학술대회논문집
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• 1990.10b
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• pp.1424-1429
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• 1990

This paper presents an indirect adaptive control scheme for discrete linear systems whose parameters are not necessrily slowly varying. It is assumed that system parameters are modelled as linear combinations of known bounded functions with unknown constant coefficients. Unknown coefficients are estimated using a recursive least squares algorithm with a dead zone and a forgetting factor. A control law which makes the estimated model exponentially stable is constructed. With this control law and a state observer, all based on the parameter estimates, it is shown that the resulting closed-loop system is globally stable and robust to bounded external disturbances and small unmodelled plant uncertainties.

• 제어로봇시스템학회:학술대회논문집
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• 1986.10a
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• pp.244-247
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• 1986

A revised two-level costate prediction algorithm is developed for the optimization of nonlinear nuclear power plant. The algorithm is proved to converge very well, and appears to require substantially small computation time and storage than previous nonlinear optimization algorithm. To cope with unknown external disturbances, we construct a closed loop control system. In order to get a smaller sampling time, this paper proposes the two-level Kalman filter.

• 제어로봇시스템학회:학술대회논문집
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• 2000.10a
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• pp.348-348
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• 2000

In this paper, we present a fuzzy moving sliding mode control for two-degrree-of-freedom robotic manipulator. 17he sliding surface parameters are designed by fuzzy inference. The proposed sliding mode control makes the error always remain on the surface from beginning and therefore, the system is insensitive to system uncertaintics and external disturbances. Simulation results show the effectiveness of proposed scheme.