• 제어로봇시스템학회:학술대회논문집
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• 1996.10b
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• pp.747-750
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• 1996

This paper considers the problem of robust H$_{\infty}$ control with regional stability constraints via output feedback to assure robust performance for uncertain linear systems. A robust H$_{\infty}$ control problem and the generalized Lyapunov theory are introduced for dealing with the problem, The output feedback H$_{\infty}$ controller makes the controlled outputs settle within a given bound and the control input not to be saturated. The regional stability constraints problem for uncertain systems can be reduced to the problem for the nominal systems by finding sufficient bounds of variations of the closed-loop poles due to modeling uncertainties. A controller design procedure is established using the Lagrange multiplier method. The controller design technique was illustrated on the track-following system of a optical disk drive.ve.

• Journal of Institute of Control, Robotics and Systems
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• v.4 no.5
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• pp.592-599
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• 1998

In this paper, we design a tracking controller which satisfies transient response specifications and maintains tracking error within a tolerable limit for the uncertain track-following system of an optical disk drive. To this end, a robust $H_{\infty}$ control problem with regional stability constraints and sinusoidal disturbance rejection is considered. The internal model principle is used for rejecting the sinusoidal disturbance caused by eccentric rotation of the disk. We show that a condition satisfying the regional stability constraints can be expressed in terms of a linear matrix inequality (LMI) using the Lyapunov theory and S-procedure. Finally, a tracking controller is obtained by solving an LMI optimization problem involving two linear matrix inequalities. The proposed controller design method is evaluated through an experiment.

• Transactions of the Korean Society for Noise and Vibration Engineering
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• v.14 no.9 s.90
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• pp.827-836
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• 2004

In this paper, we design a robust multi-objective track-following controller that satisfies transient response specifications and diminishes the influence of sinusoidal disturbance. To this end, a robust control problem with the multiple constraints is considered. We show that a sufficient condition satisfying the robust control problem can be expressed by linear matrix inequalities. Finally, the robust track-following controller can be designed by solving an LMI optimization problem. The effectiveness of the proposed controller design method is verified though experiments.

• Proceedings of the KSR Conference
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• 2011.10a
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• pp.2456-2463
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• 2011

Conventional railways are less competitive than other land transportation means in term of speed, and thus users preference and transportation share for rail system are relatively lower than others. For example, most of the conventional lines except the Seoul~Busan corridor run at an average speed of 70 km/h or less, which imposes certain constraints on roles and functions as the trunk lines. In this regard, the speed of the conventional lines should be improved up to 200 km/h to gain competitiveness, promote balanced regional development and lead the era of low carbon green growth. As track system is one of the most important elements for the speed-up, it is critical to come up with optimum technical solutions. Improvement of ballast track structure with efficient track installation can provide structural stability for higher speed and ensure operational safety with lower maintenance efforts. Thus, this study focuses on consequences followed by the speed-up including increase of load imposed on the track and impacts on track components, and provide solutions for track maintenance by analyzing impact on the track structure by speed. Also, it compares ballast and concrete tracks under designing and construction and considers how to meet needs for passengers comfort and environmental requirements as a strategic approach.