• Journal of Navigation and Port Research
• /
• v.39 no.6
• /
• pp.457-463
• /
• 2015

A gas turbine engine plays an important role as a prime mover that is used in the marine transportation field as well as the space/aviation and power plant fields. However, it has a complicated structure and there is a time delay element in the combustion process. Therefore, an elaborate mathematical model needs to be developed to control a gas turbine engine. In this study, a modeling technique for a gas generator, a PLA actuator, and a metering valve, which are major components of a gas turbine engine, is explained. In addition, sub-models are obtained at several operating points in a steady state based on the trial running data of a gas turbine engine, and a method for controlling the engine speed is proposed by designing an NPID controller for each sub-model. The proposed NPID controller uses three kinds of gains that are implemented with a nonlinear function. The parameters of the NPID controller are tuned using real-coded genetic algorithms in terms of minimizing the objective function. The validity of the proposed method is examined by applying to a gas turbine engine and by conducting a simulation.

• Proceedings of the Korea Water Resources Association Conference
• /
• 2005.05b
• /
• pp.749-754
• /
• 2005

본 연구에서는 한 개의 침투 조절 요소, 두 개의 직렬탱크 및 한 개의 병렬 탱크로 구성된 개선된 형태의 TANK 모형을 제시하였다. 침투는 강우의 형태로 유역에 공급되는 물의 분배를 결정하는 과정으로서, 이를 적절히 고려할 수 있는지의 여부가 강우-유출 모형의 유효성을 판단하는 기준이 된다고 해도 과언이 아니다. 따라서 본 연구에서는 구조가 비교적 단순하고 사용이 간편하여 기존에 널리 사용되어 오던 개념적 모형인 TANK 모형에 침투 조절 요소를 도입하여 보다 합리적으로 강우-침투-유출 과정을 모의하고 해석하고자 노력하였다. 이를 통해 단순히 시간의 함수가 아닌 토양 함수량의 함수로서 침투능의 변화를 고려할 수 있으며, 유역 유출의 각 성분(지표면 유출, 중간 유출, 지하수 유출)에 영향을 미치는 모형의 매개변수에 물리적 의미를 더욱 부여할 수 있다. 또한 침투 조절 요소의 매개변수 산정을 위해 선행 강우 지수(Antecedent Precipitation Index)를 이용하였으며, 이를 통해 토양 선행 함수 상태의 고려가 가능하다. 또한 본 연구에서는 모형의 매개변수 최적화를 위해 실수 코딩 유전 알고리즘(Real Coded Genetic Algorithm)을 사용하였으며, 모형의 적용성과 유효성 검증을 위해 IHP 연구 유역인 평창강 방림 유역을 대상유역으로 하여 이 유역의 실측 호우 사상을 사용하였다. 결과적으로 계산된 수문곡선은 관측치에 비교적 잘 일치하며, 단일 호우와 복합 호우 사상 모두에 대해 비교적 양호한 결과를 나타내었다.

• Journal of Advanced Marine Engineering and Technology
• /
• v.30 no.6
• /
• pp.753-759
• /
• 2006

Integrating processes are frequently encountered in process industries. In this paper, new tuning formulae of the PID controllers for set-point tracking and load disturbance rejection are presented for integrating processes involving time delay. First, the controller parameter sets are tuned using a real-coded genetic algorithm (RCGA) such that performance criterion(IAE, ISE or ITSE) is minimized. Then, tuning rules are addressed using tuned PID parameter sets. tuning model and another RCGA. The performances of the proposed rules are tested on two processes.

• Journal of Advanced Marine Engineering and Technology
• /
• v.32 no.5
• /
• pp.785-790
• /
• 2008

A technique for determining the feedback gain of the states feedback controller using a real-coded genetic algorithm(RCGA) is presented. It is concerned with the states error to the performance index of a RCGA. As for assessing the performance of the controller three performance criteria (ISE. IAE and ITAE) are adopted. And designing the controller involves a constrained optimization problem. Therefore a real-coded genetic algorithm incorporating the penalty strategy is used. The performance of the proposed method is demonstrated through a set of simulation about an inverted pendulum system.

• Journal of Advanced Marine Engineering and Technology
• /
• v.31 no.4
• /
• pp.448-454
• /
• 2007

The new tuning rules of the PID controller for the rejection of load disturbance are proposed incorporating with real-coded genetic algorithms (RCGAs). The optimal gain parameters of the PID controller for a first-order plus time delay model are obtained based on a RCGA. Then tuning formula are derived using the tuned parameters sets potential tuning rule models and another RCGA. The performance criteria of the controller are adopted as ISE, IAE and ITAE. A series of simulation are carried out to verify the effectiveness of the proposed tuning rules.

• Journal of Navigation and Port Research
• /
• v.32 no.5
• /
• pp.379-385
• /
• 2008

In this paper, we presents a scheme for the parameter estimation and optimal control scheme for apparatus of container crane system. For parameter estimation, first, we construct the open loop of the container crane system and estimate its parameters based on input-output data, a real-coded genetic algorithm(RCGA) and the model adjustment technique. The RCGA plays an important role in parameter estimation as an adaptive mechanism. For controller design, state feedback gain matrix is searched by another RCGA and the estimated model. The performance of the proposed methods are demonstrated through a set of simulation and experiments of the experimental apparatus.

• Journal of Navigation and Port Research
• /
• v.31 no.8
• /
• pp.697-703
• /
• 2007

In this paper, we focuses on the development of Takagi-Sugeno (T-S) fuzzy modeling in a nonlinear container crane system. A T-S fuzzy model is characterized by fuzzy "if-then" rules which represent the locally input-output relationship whose consequence part is described by a state space equation as subsystem. The T-S fuzzy model in container cranes first obtains a few number of linear models according to operation conditions and blends these conditions using fuzzy membership functions. Parameters of the membership functions are adjusted by a RCGA to have same dynamic characteristics with nonlinear system of a container crane. Simulations are given to illustrate the performance of T-S fuzzy model.

• Proceedings of the Korean Institute of Navigation and Port Research Conference
• /
• 2007.12a
• /
• pp.304-306
• /
• 2007

In this paper, we presents a scheme for the parameter estimation and optimal control scheme for apparatus of container crane system. For parameter estimation, first, we construct the open loop of the container crane system and estimate its parameters based on input-output data, a real-coded genetic algorithm(RCGA) and the model adjustment technique. The RCGA plays an important role in parameter estimation as an adaptive mechanism. For controller design, state feedback gain matrix is searched by another RCGA and the estimated model. The performance of the proposed methods are demonstrated through a set of simulation and experiments of the experimental apparatus.

• Journal of the Korean Institute of Intelligent Systems
• /
• v.12 no.1
• /
• pp.33-38
• /
• 2002

In this paper, a Two-Degree-of-Freedom-Controller(TDFC) for DC motors based on inverse dynamics and the fuzzy technique is presented. The proposed controller includes the inverse dynamic model of a DC motor system, a prefilter and a fuzzy compensator. The model of the system is characterized by a nonlinear equation with coulomb friction. The prefilter eliminates high frequency effects occurring when the inverse dynamic model is implemented. The fuzzy compensator is designed for tracking the change of the reference input and simultaneously regulating the error between the reference input and the system output which can be caused by disturbances. The optimal parameters of both the model and the compensator are identified by a real-coded genetic algorithm. An experimental work on a DC motor system is carried out to verify the performance of the proposed controller.

• Journal of Korea Water Resources Association
• /
• v.39 no.1 s.162
• /
• pp.47-57
• /
• 2006

This study derives an event-based tank model with a conceptual rainfall-infiltration process, modifying conventional tank models. The model comprises two serial tanks, one parallel tank and an infiltration regulating element. The infiltration process within the element is not represented as a function of only time, but as a function of soil moisture content for three possible cases owing to the relationship between rainfall intensity and infiltration capacity. This study considers the previous soil moisture condition of a watershed by using antecedent precipitation index. Six parameters of the model are identified by using the real coded genetic algorithm. The applicability and validity of the proposed model are assessed for the observed stormwater data from the research basin of the International Hydrological Program, the Pyeongchanggang River basin, Republic of Korea. The results computed streamflows show relatively good agreement with observed ones.