• 제어로봇시스템학회:학술대회논문집
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• 제어로봇시스템학회 2004년도 ICCAS
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• pp.232-237
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• 2004

In many application of DC-DC converters, loads cannot be specified in advance, i.e., their amplitudes are suddenly changed from the zero to the maximum rating. Generally, design conditions are changed for each load and then each controller is re-designed. Then, a so-called robust DC-DC converter which can cover such extensive load changes and also input voltage changes with one controller is needed. Analog control IC is used usually for the controller of DC-DC converter. Simple integral control etc. are performed with the analog control IC. However it is difficult to retain sufficient robustness of DC-DC converter by these techniques. The authors proposed the method of designing an approximate 2-degree-of-freedom (2DOF) controller of DC-AC converter. This controller has an ability to attain sufficient robustness against extensive load and DC power supply changes. For applying this approximate 2DOF controller to DC-DC converter, it is necessary to improve the degree of approximation for better robustness. In this paper, we propose a method of designing good approximate 2DOF digital controller which makes the control bandwidth wider, and at the same time makes a variation of the output voltage very small at a sudden change of resistive load. The proposed good approximate 2DOF digital controller is actually implemented on a DSP and is connected to a DC-DC converter. Experimental studies demonstrate that this type digital controller can satisfy given specifications.

• Journal of Advanced Marine Engineering and Technology
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• 제33권8호
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• pp.1212-1219
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• 2009

본 연구에서는 실용설계의 새로운 도구로써 제어계의 강인성, 성능, 안정성 등의 설계지침을 정량화하기 쉽고 해가 효율적으로 구해져 주목받는 선형행렬부등식을 이용하여 강인한 LMI 제어기를 설계한다. 우선 다층상 구조물의 진동제어를 위해 수학적 모델링을 행하고 적분형 서보계를 적용한 LMI 제어 기법으로 상태 피드백 제어칙을 설계한다. 다음으로 설계한 제어칙으로 시스템 불확실성의 변동에 대해 시간영역의 설계사양을 고려한 경우와 고려하지 않은 경우에 대하여 시뮬레이션을 행하고 실제 적용 가능성을 검토한다.

• 한국생산제조학회지
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• 제5권2호
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• pp.63-72
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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 Constraint (ACC) system was developed. The feedrate override function was accomplished through a development of programmable machine controller (PMC) interface technique on the NC controller, Nonlinear model of the cutting process was linearized as an adaptive model with a time varying process parameter. An integral type estimator was introduced for on-line estimation of the cutting process parameter, Zero order hold digital control methodology which uses pole-assignment concept for tuning of PI controllers was applied for the ACC system. Performance of the ACC system wsa confirmed on the vertical machining center equipped with fanuc OMC through a large amount of experiment.

• 제어로봇시스템학회:학술대회논문집
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• 제어로봇시스템학회 2001년도 ICCAS
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• pp.121.2-121
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• 2001

Many of today´s robot are required to perform tasks which demand a high level of accuracy in end-effector positioning. Those rigid robots are very inefficient and slow because its have large and heavy links, In an attempt to solve these problems, a robots using flexible beam were created. But the single-link flexible beam is infinite-dimensional system. Many researchers have proposed controlling such a beam an approximated model consisting of a finite a number of models. In this paper, we start by deriving the analytic model for the dynamics of general single-link beam, and a controller is designed for flexible beam with integral type servo system bases of the linear matrix inequality (LM) technique. To the end, simulation results show that a designed controller guarantees affective vibration control the single-link flexible beam.

• International Journal of Control, Automation, and Systems
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• 제6권2호
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• pp.194-203
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• 2008

Iterative learning control (ILC) is a simple and effective method for the control of systems that perform the same task repetitively. ILC algorithm uses the repetitiveness of the task to track the desired trajectory. In this paper, we propose a PID (proportional plus integral and derivative) type ILC update law for control discrete-time single input single-output (SISO) linear time-invariant (LTI) systems, performing repetitive tasks. In this approach, the input of controlled system in current cycle is modified by applying the PID strategy on the error achieved between the system output and the desired trajectory in a last previous iteration. The convergence of the presented scheme is analyzed and its convergence condition is obtained in terms of the PID coefficients. An optimal design method is proposed to determine the PID coefficients. It is also shown that under some given conditions, this optimal iterative learning controller can guarantee the monotonic convergence. An illustrative example is given to demonstrate the effectiveness of the proposed technique.

• International Journal of Aeronautical and Space Sciences
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• 제8권1호
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• pp.32-45
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• 2007

The T-50 advanced supersonic jet trainer employs the Relaxed Static Stability (RSS) concept to improve the aerodynamic performance while the flight control system stabilizes the unstable aircraft and provides adequate handling qualities. The T-50 flight control laws employ a proportional-plus-integral type controller based on a dynamic inversion method in longitudinal axis and a proportional type controller based on a blended roll system with simple roll rate feedback and beta-betadot feedback system. These control laws are verified by flight tests with various maneuver set flight envelopes and the control laws are updated to resolve flight test issues. This paper describes several concepts of flight control laws used in T-50 to resolve those flight test issues. Control laws for solving the roll-off problem during pitch maneuver in asymmetric loading configurations, improving the departure resistance in negative angle of attack conditions and enhancing the fine tracking performance in air-to-air tracking maneuvers are described with flight test data.

• 제어로봇시스템학회논문지
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• 제16권11호
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• pp.1029-1037
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• 2010

If an internal combustion engine is operated by consolidated control, the minimum fuel consumption is achieved and the demanded objectives are satisfied. For this, it is necessary that the engine is operated on the ideal operating line which satisfies minimum fuel consumption. In this context of view, there are many tries to achieve given object. However, the parameters in the internal combustion engines are variable and depend on the operating points. Therefore, it is necessary to cope with the uncertainties such that the optimal operating may be possible. From this point of view, this paper gives a controller design method and a robust stability condition for engine torque control which satisfies the given control performance and robust stability in the presence of physical parameter perturbation. Exactly, in this paper, we consider the robust stability problem of this 2DOF servosystem with nonlinear type uncertainty in the engine system, and a robust stability condition for the servosystem is shown. This result guarantees that if the plant uncertainty is in the permissible set defined by the given condition, then a gain tuning can be carried out to suppress the influence of the plant uncertainties.

• 대한기계학회논문집A
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• 제36권7호
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• pp.797-803
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• 2012

비례솔레노이드밸브는 코일전류에 비례하는 전자기력을 이용하여 밸브 변위를 연속적으로 가변시키는 밸브이다. 대용량 비례유량제어밸브는 발전소나 화학 플랜트에서 물, 스팀, 가스 등과 같은 공정유체의 대용량 유량제어에 사용되며 공압이나 모터를 이용하는 밸브에 비하여 우수한 응답성능과 소형화의 장점을 가진다. 본 연구에서는 비례제어밸브를 대상으로 밸브의 동적 특성을 식별한 후 목표 성능이 만족되도록 위치제어기의 비례적분이득을 자동으로 조정하는 기능을 설계하였다. 동특성 식별은 릴레이 피드백을 통하여 한계 안정 상태에서의 임계이득과 임계주기로 파악하였으며, 비례적분이득 결정에는 Ziegler-Nichols 방법을 적용하였다. 구현된 기능은 시험을 통하여 성능을 검증하였으며 밸브 작동점과 릴레이 제어기 변수가 자동조정에 미치는 영향을 분석하였다.

• 조명전기설비학회논문지
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• 제12권3호
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• pp.29-36
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• 1998

본 연구에서는 제어시스템과 규범모델 사이의 스텝응답의 오차적분올 최소화하여 모델추종법에 기초한 디지탈 PID제어기의 설계법을 제안한 것이며, 전류형인버터 구동유도전동기의 속도제어에 적용했고, 시스템의 동특성을 스댐웅답으로 나타냈다. PlD제어기의 최적파라메터는 행렬연산으로 쉽게 구할 수 있으며, 계산도 간단하며 계통 적인 설계과정을 통하여 일률적으로 처리된다. 끝으로, 스댐상의 목표치 변화 및 외란에 대해서도 안정하고 정상편차가 없는 운전결과를 컴퓨터 시뮬레이션으로 나타냈고 실험적으로 그 결과를 확인하였다.

• 융합신호처리학회논문지
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• 제4권4호
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• pp.47-51
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• 2003

디지털제어에 잘 사용되어 온 유한정정제어를 연속계에 적용하기는 연속계의 점근성 때문에 어려운 것으로 알려져 있다. 그러나 유한 Laplace변환을 전달함수에 적용하고 여기에 정정조건을 적용하여 제어기를 설계한 연속계 유한정정제어기(CDBC, Continuous-time Deadbeat Controller)에 대해서 연구가 되고 있다. 이에 따라 지연요소가 전달함수에 사용되어 정정을 위한 차수 및 보간조건이 유도되어 제어기가 설계되거나, 디지털 유한정정제어기를 설계하고 이를 연속계 제어기로 변환하기 위해 평활요소로 사용하여 CDBC를 구성하기도 한다. 본 논문에서는 다중 샘플링을 적용하여 제어기와 출력귀환루프의 샘플링 속도를 달리하였으며, 2차 평활요소를 디지털 유한정정제어기에 사용한 CDBC를 연구한다. 이러한 다중 샘플링은 샘플링 주기 동안에 제어루프를 또 샘플링하여 전체적인 출력응답을 개선할 수 있다. 제어기는 직렬 적분 보상기를 전향경로에 배치하고 지역 귀환보상기를 귀환 루프에 도입한다. Matlab Simulink을 사용하여 시뮬레이션을 한다.