• Proceedings of the KIEE Conference
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• 1992.07a
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• pp.282-284
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• 1992

In this paper, we deal with design method of two-degree-of-freedom control system which desired property of robustness and tracking can be achieved simultaneously, Controller is designed by means of model matching method and H$\infty$ weighted sensitivity minimization design method. Satisfactory result of design example is obtained by simulation.

• Journal of Advanced Marine Engineering and Technology
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• v.20 no.3
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• pp.144-153
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• 1996

The magnetic levitation system has many advantages, such as little friction, no lubrication, no noise and so on. For this reason, the magnetic levitation system is utilized in the magnetic bearing of high-speed rotor. The method to obtain magnetic force is both the repulsive suspension method and the attraction suspension method need a stabilizing controller because it is a unstable system in natural. This paper presents the design of robust stabilizing servo controller in spite of being the model uncertainties in the magnetic levitation system by $\textit{H}_{\infty}$ control theory using the free parameter. And we investigated the validity of a designed controller through results of the simulation and the actual experiment.

• The Transactions of the Korean Institute of Electrical Engineers A
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• v.52 no.1
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• pp.1-8
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• 2003

This paper presents a novel application method of H$_{\infty}$ optimization method to the design of Power System Stabilizer(PSS) and experimental results through hardware simulator. The approach is focused on decision of performance index and selection strategy of weighting functions together with its tuning for direct design. As the Purpose of the PSS is to increase system damping at very narrow frequency band, weighting functions are determined differently from the case of general servo system control. The designed PSS was confirmed through experiments on a hardware simulator.

• 제어로봇시스템학회:학술대회논문집
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• 2000.10a
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• pp.21-21
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• 2000

In this paper, we design the state feedback gain using linear matrix inequality(LMI) to the multiobjective synthesis, in the magnetic bearing system with integral type servo system. The design objectives can be a H$\_$$\infty$/ performance, asymptotic disturbance rejection, time-domain constraints, on the closed-lnp pole location. To the end, we investigated the validity of the designed controller through results of simulation.

• Journal of the Korean Institute of Gas
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• v.3 no.2 s.7
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• pp.62-69
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• 1999

This paper presents a design method of dynamic positioning control system(DPS) for floating Platform with rotatable and retractable thrusters using H$\infty$ servo control design method. The norm band of uncertainty is captured by multiplicative perturbation between nominal model and reduced order model. A controller robust to the uncertainty is designed applying H$\infty$ synthesis. The control law satisfying robust stability and nominal performance condition is determined through the mixed sensitivity approach. The control algorithm was evaluated on the basis of computer simulation for a proposed DPS design method and experiments was carried out with an image processing method for measurement of DPS position in a water tank The results of overall experiments show that proposed control method will be good to keep at a specified position. And they are compared with the experimental results by LQG synthesis and H$\infty$ optimal control design method.

• Proceedings of the KIEE Conference
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• 2001.07e
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• pp.17-19
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• 2001

In this paper, we constitute H/W systems for the accurate control of DC servo motor. This H/W systems are designed by applying a simple genetic algorithm (SGA) to the robust $H_{\infty}$ control system and the intelligent Fuzzy control system of DC motor, respectively. To verify the effectiveness of the proposed systems, the characteristics of this systems are analysed and simulated.

• Proceedings of the Korean Society for Noise and Vibration Engineering Conference
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• 1996.04a
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• pp.119-124
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• 1996

Recently, high speed optical disk drives are increasingly demanded to read or write data fastly enough. To this end, both structure and controller designs of their optical pick-ups should be improved concurrently. In this paper, the pick-up during auto-focusing motion is mathematically modelled retaining all its peculiar features. The model turns out a linear time invariant system suitable for a control design method named H$_{\infty}$ which ensures robust stability in the presence of system uncertainties. Numerical simulation are performed to demonstrate the controller robustness with appropriate performance specifications being satisfied..

• Journal of KSNVE
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• v.6 no.4
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• pp.521-528
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• 1996

Recently, higher speed optical disk drives including computer CD-ROM drives tend to be increasingly demanded to read or write the enormous volume of digital data. To this end, both structure and controller designs of the optical pick-ups should be improved concurrently. In this paper, the pick-up during auto-focusing motion is mathematically modelled retaining all its peculiar features. The model turns out a linear time invariant system suitable for a control design namedH${\infty}$ which ensures robust stability in the presence of system uncertainties. Numerical simulations are performed to demonstrate the robustness with appropriate performance specifications being satisfied. In addition, as the implementation issue of it, procedures of temporal discretization as well as model reduction of the controller are also addressed.

• Transactions of the Korean Society of Mechanical Engineers A
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• v.20 no.6
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• pp.1882-1892
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• 1996

This paper is concerned with the position control of the ond degree-of freedom manipulator using pneumatic artificial muscle actuator which is built to have a proper compliance. For t his pneumatic artificial muscle actuator though, it is difficult to make an effective control scheme due to the nonlinearity and uncertainties on the dynamics of the actuator. In this paper, a third-order equation of motion is derived for the actuator including the dynamics of the pneumatic servovalve. Later, various modeling uncertainties due to the nonlinearity and unmodeled dynamics of the servo vlave and the actuator are taken care of, as a trade-off between the closed-loop performance of the controlled system and its robustness to uncertainties. A controller using .mu. synthesis thchnique is designed, and robust performance against measurement noise, various modeling uncertainties due to the dynamics of the servo valve and actuator is achieved. The effectiveness of the proposed control methods is illustrated through simulations and experiments.

• Journal of the Institute of Electronics Engineers of Korea SC
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• v.45 no.3
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• pp.32-41
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• 2008

In this paper, we describe the synthesis of robust and non-fragile $H^{\infty}$ state feedback controllers for linear systems with affine parameter uncertain tracking servo system of blu-ray disc drive, as well as static state feedback controller with polytopic uncertainty Similarity any other control system, the objective of the track-following system design for optical disc drives is to construct the system with better performance and robustness against modeling uncertainties and various disturbances. Also, the obtained condition can be rewritten as parameterized linear matrix inequalities(PLMIs), that is, LMIs whose coefficients are functions of a parameter confined to a compact set. We show that the resulting controller guarantees the asymptotic stability and disturbance attenuation of the closed loop system in spite of controller gain variations within a resulted polytopic region.