• 한국해양공학회지
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• 제17권2호
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• pp.60-66
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• 2003

In this paper, an actively controlled anti-rolling system is considered, in order to reduce the rolling motion of a ship. In this control system, a small auxiliary mass is installed on the upper area of the ship, and an actuator is connected between the auxiliary mass and the ship. The actuator reacts the auxiliary mass, applying inertial control forces to the ship to reduce the rolling motion in the desired manner. In this paper, we introduce LMI based H$_{\infty}$ control approach to design the anti-rolling control system for the controlled ship. And the experimental results show that the desirable control performance can be achieved.

• 제어로봇시스템학회:학술대회논문집
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• 제어로봇시스템학회 2000년도 제15차 학술회의논문집
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• pp.498-498
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• 2000

A study on the robust control of a composite beam with a distributed PVDF sensor and piezo-ceramic actuator is presented in this paper. 1st and 2nd natural frequencies are considered in the modeling, because robust control theory which has robustness to structured uncertainty is adopted to suppress the vibration. If the controllers designed by H$_{\infty}$ theory do not satisfy control performance, it is improved by $\mu$-synthesis method with D-K iteration so that the $\mu$-controller based on the structured singular value satisfies the nominal performance and robust performance. Simulation and experiment were carried out with the designed controller and the verification of the robust control properties was presented by results.

• 제어로봇시스템학회:학술대회논문집
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• 제어로봇시스템학회 2001년도 ICCAS
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• pp.34.2-34
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• 2001

There are many control methods guaranteeing the robustness of systems. Among them, H$\infty$ control, sliding mode control and disturbance observer have been used widely. Especially, disturbance observer(DOB) is one of the most popular methods because it is easy to apply and the cost to pay is low due to its simplicity. Conventional DOB utilizes output signal as a feedback signal. But in Optical Disk Drive(ODD) systems, the Position Error Signal(PES) is the only available one. So conventional DOB is not applicable. If we use error signal in stead of output signal, another form of DOB is made. We call it as Error based Disturbance Observer(EDOB). We show in this paper the difference between two systems, namely conventional DOB system and the EDOB system, and also show the effectiveness of EDOB through experiment.

• 제어로봇시스템학회:학술대회논문집
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• 제어로봇시스템학회 2001년도 ICCAS
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• pp.22.5-22
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• 2001

Robust control of a GFR composite beam with a distributed PVDF sensor and piezo-ceramic actuator is presented En this paper. Modal analysis method and modal coordinates are introduced to obtain the state educations of the structural system. 1st and 2nd natural frequencies are considered In the modeling, because robust control theory which is robustness to structured uncertainty is adopted to suppress the vibration. If the controllers designed by H$\^$$\infty$/ theory do not satisfy control performance, it is improved by ${\mu}$-synthesis method with D-K Iteration so that the ${\mu}$-controller based on the structured singular value satisfies the nominal performance and robust performance.

• 한국지능시스템학회논문지
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• 제20권5호
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• pp.617-623
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• 2010

본 논문에서는 차륜형 역진자에 적용되는 LMI 제어기 설계와 그 수치 시뮬레이션이 수행되었다. 차륜형 역진자는 2개의 평형점을 갖고 있는 역진자의 일종이다. 불안정한 평형점에 대하여 평형을 유지하기 위하여 차륜형 역진자는 지속적으로 제어되어야 한다. 경사면을 고려하여 차륜형 역진자의 동역학 방정식이 유도되었다. 경사면을 적극적으로 고려하여 차륜형 역진자를 안정화 시킬 수 있는 제어기를 구성하는데 선형행렬부등식 기법이 적용되었다. LMI 기반 제어기가 평면과 경사면에 대해서 유효함을 보이기 위해서 다양한 수치 시뮬레이션이 수행되었다.

• 대한기계학회논문집A
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• 제24권2호
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• pp.290-302
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• 2000

In this paper, we study on the identification of discrete-time state-space model for robust control of tandem cold mill, using a MOESP(MIMO output-error state-space model identification) algorithm based on subspace method. It is shown that the identified model is well adapted to input-output data sets, which are obtained from nonlinear mathematical equations of tandem cold mill. Furthermore, deterministic H$\infty$ norm bounds on uncertainties including modeling errors and disturbances are quantitatively identified in the frequency domain. Finally, the results give a basic idea to determine weighting functions included in formulating some robust control problems of tandem cold mill.

• 전기학회논문지
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• 제67권2호
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• pp.261-269
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• 2018

In this paper, we propose a Takagi-Sugeno (T-S) fuzzy-model-based design for the tracking control of a class of nonlinear underwater glider. By using the partial linearization and the sector nonlinearity, the underwater glider with six degrees of freedom (6 DOF) is modelled by the T-S fuzzy model. The concerned tracking control problem with $H_{\infty}$ performance is converted into the stabilization one for the error dynamics between the given nonlinear underwater glider and the reference time-varying input. Sufficient conditions are derived for the asymptotic stabilizability of the error dynamics in the format of matrix inequality. Simulation results demonstrate the effectiveness of the proposed design methodology.

• 대한기계학회논문집A
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• 제25권10호
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• pp.1501-1513
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• 2001

Disturbance observer, adaptive robust control, and enhanced internal model control are model based disturbance attenuation methods famous for robust motion controller which can satisfy desired performance and robustness of high-speed/high-accuracy positioning systems. In this paper, these are shown to be the same scheme with different parameterizations. To do this, a generalized framework, called as RIC(robust internal-loop compensator) is proposed and the conventional schemes are analyzed in the RIC framework. Through this analysis, it can be shown that there are inherent similarities between the schemes and advantages of the RIC in the viewpoint of controller design. This is verified through simulations and experiments.

• 제어로봇시스템학회:학술대회논문집
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• 제어로봇시스템학회 2001년도 ICCAS
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• pp.38.2-38
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• 2001

Recent trend of increasing automated factories needs supply of high quality power from the utilities. Among the items of the power quality, voltage sag can be compensated by Dynamic Voltage Restorer(DVR). The key feature of the DVR is high response with less transient period to recover from the voltage sag due to the lightning or line-to-ground faults. In this paper we report that H controller is very premising for the practical application to the controller of DVR. Experiment al results shown in this paper was obtained by applying the control algorithm to 20 kVA DVR system. The experimental set consist s of IGBT - based three phase inverter and the TMS320C32- 60 DSP used for main processor of the control board. T$\infty$ simulate the 50% voltage ...

• 동력기계공학회지
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• 제9권2호
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• pp.65-72
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• 2005

A new approach is presented to design a robust sampled-data controller for an experimental flexible beam carrying an unknown payload at its free end. The purpose of this paper is to move the free end of the beam to a desired position in the specified time under vibration suppression. We derive a transfer function nominal model for the beam and quantitative description of model uncertainties based on experimentally obtained frequency response data. Robust controllers are designed by applying the sampled-data $H_{\infty}$ control and ${\mu}m-theory$, in which two types of uncertainties, structured and unstructured uncertainties, are adopted for satisfactory performance in terms of hinge position regulation and vibration damping, besides obviously asymptotic stability. The effectiveness of the proposed method is confirmed through simulation and experimentation.