• 대한전기학회:학술대회논문집
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• 대한전기학회 2005년도 학술대회 논문집 정보 및 제어부문
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• pp.514-516
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• 2005

압전 구동기(Piezo actuator)는 수 나노미터 수준의 위치정밀도와 고분해능을 가지고 있으나 비선형 특성인 히스테리시스(Hysteresis)는 정상상태에서 위치 오차를 발생하는 주요 원인이 된다. 현재까지 히스테리시스를 보상하기 위해 피 프 포워드 제어 방법, Pl 제어 방법, $H_{\infty}$제어 방법 등이 연구되어 왔지만 저주파 대역의 외란(disturbance)까지 고려하여 시스 템을 주파수 영역에서 설계, 분석하는 방법에 대한 연구는 미흡하였다. 본 논문은 압전 구동기의 위치 제어를 위한 제어기의 설계와 이를 주파수 영역에서 분석하는 내용을 다룬다. 제어기의 설계는 히스테리시스를 보상하기 위해 극점 배치 방법과 외란 관측기(Disturbance observer)를 기본으로 하였으며 적분제어를 적용하여 시스템 민감도(sensitivity)를 개선하였다. 시뮬레이션과 실험을 통하여 설계한 제어기가 히스데리시스에 대한 보상과 민감도의 개선에 효율적임을 검증하였다.

• 대한전자공학회:학술대회논문집
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• 대한전자공학회 1998년도 하계종합학술대회논문집
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• pp.219-222
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• 1998

This paper presents the Mixed H2/H$\infty$ controller design method with the regional pole placements for underwater vehicle. Since the small and light underwater vehicle is sensitive to disturbances and parameter uncertainties, we design the controller which guarantees robustness against time-delays, parameter uncertainties and disturbances. The LMI(linear matrix inequality) formulations for pole placements in specific regions and H2 and H$\infty$ performances are reviewed. The desired controller can be obtained by solving these LMIs.

• 대한전기학회:학술대회논문집
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• 대한전기학회 1987년도 전기.전자공학 학술대회 논문집(I)
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• pp.241-243
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• 1987

• 전기의세계
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• 제31권4호
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• pp.296-302
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• 1982

The computer algorithm and program are developed to obtain the Luenberger Canonical form and the transform matrices for linear time invariant multivariable control systems. The model controller of an eigth order system, which assigns the modes of the multivariable control systems and closed-loop matrices are computed numerically by the developed programs. It is shown that the computed results coincide with the Luenberger's and Kalman's method. The gain of the model controller has varied from 10$^{-3}$ to 10$^{5}$ by the modes assignment of the open-loop system.

• 한국정밀공학회:학술대회논문집
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• 한국정밀공학회 1996년도 추계학술대회 논문집
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• pp.690-694
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• 1996

In order to regulate the cutting force at a desired level during peripheral end milling processes, a feedrate override Adaptive Control Constant system was developed. This paper presents an explicit pole-assignment PI-control law through spindle motor current monitoring and its application to cutting force regulation for feedrate optimization. An experimental set-up is constructed for the commercial CNC machining center without any major changes of the structure. A data transfer system is constructed with standard interface between an IBM compatible PC and a CNC of the machining center. Experimental results show the validity of the system.

• 제어로봇시스템학회논문지
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• 제1권2호
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• pp.78-82
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• 1995

In this paper, we consider the robustness analysis problem in state space models with linear time invariant perturbations. Based upon the discrete-time Lyapunov approach, sufficient conditions are derived for the eigenvalues of perturbed matrix to be located in a circle, and robustness bounds on perturbations are obtained. Spaecially, for the case of a diagonalizable hermitian matrix the bound is given in terms of the nominal matrix without the solution of Lyapunov equation. This robustness analysis takes account not only of stability robustness but also of certain types of performance robustness. For two perturbation classes resulting bounds are shown to be improved over the existing ones. Examples given include comparison of the proposed analysis method with existing one.

• 한국소음진동공학회논문집
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• 제20권10호
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• pp.900-906
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• 2010

This note proposes vibration-free motor control through modified LQG/LTR methodology. A conventional LQG/LTR method is a design tool in the frequency domain. However, unlike the conventional one, the proposed one is a time response based design method. This feature is firstly designed by parameterized settling time control gain through the target loop design procedure and the feature is secondly realized by loop transfer recovery. In order to show convergence to the target loop transfer functions, asymptotic behaviors of the open and the closed loop transfer functions are shown. At the conclusion, it is verified that the proposed method is robustly stable to parametric uncertainties through ${\mu}$-plot.

• 한국기계가공학회지
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• 제20권4호
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• pp.66-72
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• 2021

Since the behavior of an autonomous underwater vehicle (AUV) is influenced by disturbances and moments that are not accurately known, the depth control law of AUVs must have the ability to track the input signal and to reject disturbances simultaneously. Here, we proposed robust tracking control for controlling the depth of an AUV. An augmented closed-loop system is represented by an error dynamic equation, and we can easily show the asymptotic stability of the overall system by using a Lyapunov function. The robust tracking controller is consisted of the internal model of the command signal and a state feedback controller, and it has the ability to track the input signal and reject disturbances. The closed-loop control system is robust to parameter uncertainties. Simulation results showed the control performance of the robust tracking controller to be better than that of a P + PD controller.

• 대한전자공학회:학술대회논문집
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• 대한전자공학회 2000년도 하계종합학술대회 논문집(1)
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• pp.127-130
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• 2000

In this paper, we design the robust H$_{\infty}$ controller for congestion control in ATM (asynchronous transfer mode) networks with the variation of other higher priority sources(e.g., constant bit rate, variable bit rate). Since ABR (available bit rate) sources share the bottleneck node with other higher priority sources, we design the controller which guarantees robustness against time delay and disturbance. The proposed robust H$_{\infty}$ controller with regional pole placements can minimize the variation of the queue size at the predefined desired level. And we also show its robustness through simulation for the ATM networks with time delay and disturbance.

• 한국통신학회논문지
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• 제18권3호
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• pp.372-384
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• 1993

로보트 제어와 로케트의 자세 제어에 관련하여 도립 진자 시스템은 제어 이론과 응용면에서 흥미 있는 문제이다. 일반적으로 도립 진자 시스템을 제어하기 위하여 소신호 모델에 의한 근사화 모델이 사용되었다. 본 논문에서는 미분 다양체 이론을 기초로 한 비선형 제어 이론을 도입 진자 시스템에 적용하고자 한다. 먼저 비선형 모델을 비선형 상태 궤환을 이용하여 근사 선형화 모델로 변환시키고, 선형화 모델에 극점 배치를 통하여 선형 제어기를 설계하였다. 컴퓨터 시뮬레이션을 통하여 제안된 기법을 Tayler 급수의 3차 선형화모델과 비교하였다.