• 한국소음진동공학회:학술대회논문집
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• 한국소음진동공학회 2009년도 추계학술대회 논문집
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• pp.108-109
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• 2009

• 한국항해항만학회:학술대회논문집
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• 한국항해항만학회 2004년도 추계학술대회
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• pp.111-116
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• 2004

이 논문에서는 모델조정기법과 실수코딩 유전알고리즘을 이용하여 주어진 직류모터 시스템의 파라미터를 추정하였다. 종래에 논 Ziegler- Nichols(Z-N)동조법, Cohen-Coon(C-C)동조법, IMC(Internal model control)동조법, Lopez ITAE(L-ITAE)동조법과 같이 경험적이고 실험적인 많은 방법들이 제안되었다. 본 논문에서는 실수코딩 유전알고리즘을 이용하여 PID 제어기의 파라미터들을 동조하는 방법을 제안하고 시뮬레이션과 실험을 통해 제안한 제어기의 성능을 증명하였다.

• 한국항해항만학회지
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• 제44권5호
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• pp.423-429
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• 2020

A ship's automatic steering system is the basis for addressing control difficulties related to course-changing and course-keeping during navigation through heading angle control, and is a link in realizing unmanned and autonomous ships. This study proposes a robust RCGA-based linear active disturbance rejection controller (LADRC) design method considering environmental disturbances, measurement noise, and model uncertainties in designing a ship heading controller for use when the ship is sailing. The LADRC consisted of a transient profile, a linear extended state observer, and a PD controller. The control gains in the LADRC with the linear extended state observer were adjusted by RCGAs to minimize the integral of the time-weighted absolute error (ITAE), which is an evaluation function of the control system. The proposed method was applied to ship heading control, and its effectiveness was validated by comparing the propulsive energy loss between the proposed method and a conventional linear PD controller. The simulation results showed that the proposed method had the advantages of lower propulsive energy loss, more robustness, and higher tracking precision than the conventional linear PD controller.

• Journal of Electrical Engineering and Technology
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• 제8권3호
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• pp.490-498
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• 2013

This paper discusses the application of evolutionary multi-objective optimization algorithms namely Non-dominated Sorting Genetic Algorithm-II (NSGA-II) and Modified NSGA-II (MNSGA-II) for solving the Combined Economic Emission Dispatch (CEED) problem with valve-point loading. The valve-point loading introduce ripples in the input-output characteristics of generating units and make the CEED problem as a non-smooth optimization problem. IEEE 57-bus and IEEE 118-bus systems are taken to validate its effectiveness of NSGA-II and MNSGA-II. To compare the Pareto-front obtained using NSGA-II and MNSGA-II, reference Pareto-front is generated using multiple runs of Real Coded Genetic Algorithm (RCGA) with weighted sum of objectives. Furthermore, three different performance metrics such as convergence, diversity and Inverted Generational Distance (IGD) are calculated for evaluating the closeness of obtained Pareto-fronts. Numerical results reveal that MNSGA-II algorithm performs better than NSGA-II algorithm to solve the CEED problem effectively.

• Journal of Mechanical Science and Technology
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• 제20권5호
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• pp.612-620
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• 2006

This paper proposes an optimal trajectory generation method for biped robots for walking up-and-down stairs using a Real-Coded Genetic Algorithm (RCGA). The RCGA is most effective in minimizing the total consumption energy of a multi-dof biped robot. Each joint angle trajectory is defined as a 4-th order polynomial of which the coefficients are chromosomes or design variables to approximate the walking gait. Constraints are divided into equalities and inequalities. First, equality constraints consist of initial conditions and repeatability conditions with respect to each joint angle and angular velocity at the start and end of a stride period. Next, inequality constraints include collision prevention conditions of a swing leg, singular prevention conditions, and stability conditions. The effectiveness of the proposed optimal trajectory is shown in computer simulations with a 6-dof biped robot model that consists of seven links in the sagittal plane. The optimal trajectory is more efficient than that generated by the Modified Gravity-Compensated Inverted Pendulum Mode (MGCIPM). And various trajectories generated by the proposed GA method are analyzed from the viewpoint of the consumption energy: walking on even ground, ascending stairs, and descending stairs.

• 한국항해항만학회지
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• 제34권2호
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• pp.117-122
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• 2010

Since fuzzy controllers are nonlinear, it is more difficult to set the controller gains and to analyse the stability compared to conventional PID controllers. This paper proposes a fuzzy PD+I controller for tracking control which uses a linear fuzzy inference(product-sum-gravity) method based on a conventional linear PID controller. In this scheme the fuzzy PD+I controller works similar to the control performance as the linear PD plus I(PD+I) controller. Thus it is possible to analyse and design an fuzzy PD+I controller for given systems based on a linear fuzzy PD controller. The scaling factors tuning scheme, another topic of fuzzy controller design procedure, is also introduced in order to fine performance of the fuzzy PD+I controller. The scaling factors are adjusted by a real-coded genetic algorithm(RCGA) in off-line. The simulation results show the effectiveness of the proposed fuzzy PD+I controller for tracking control problems by comparing with the conventional PID controllers.

• Journal of Electrical Engineering and Technology
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• 제2권2호
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• pp.178-187
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• 2007

One important issue in power systems is dynamic instability due to loosing balance relation between electrical generation and a varying load demand that justifies the necessity of stabilization. Moreover, Power System Stabilizer (PSS) must have capability of producing appropriate stabilizing signals over a wide range of operating conditions and disturbances. To overcome these drawbacks, this paper proposes a new method for robust design of PSS by using an auto-tuning fuzzy control in combination with Real-Coded Genetic Algorithm (RCGA). This method includes two fuzzy controllers; internal fuzzy controller and supervisor fuzzy controller. The supervisor controller tunes the internal one by on-line applying of nonlinear scaling factors to inputs and outputs. The RCGA-based method is used for off-line training of this supervisor controller. The proposed PSS is tested in three operational conditions; nominal load, heavy load, and in the case of fault occurrence in transmission line. The simulation results are provided to compare the proposed PSS with conventional fuzzy PSS and conventional PSS. By evaluating the simulation results, it is shown that the performance and robustness of proposed PSS in different operating conditions is more acceptable

• 한국추진공학회:학술대회논문집
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• 한국추진공학회 2008년도 제31회 추계학술대회논문집
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• pp.23-27
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• 2008

본 논문에서는 실수코드 유전 알고리즘(RCGA)과 인공신경망(ANN)을 이용하여 항공기용 터보 축엔진의 결함 진단에 관한 연구를 수행하였다. 인공신경망만을 이용하여 엔진의 결함을 판단 할 경우 많은 학습데이터 때문에 지역 최소점으로 수렴하는 단점이 있다. 이를 개선하기 위해 전역 최소점을 찾는 능력이 뛰어난 실수코드 유전 알고리즘을 사용하였다. 5% 이내의 RMS 결함오차로 높은 결함 예측 신뢰도를 가짐을 확인하였다.

• Journal of Advanced Marine Engineering and Technology
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• 제34권1호
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• pp.109-115
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• 2010

본 논문은 퍼지 제어를 통한 이동용 로봇에 대한 추적 제어에 대해서 다루고 있다. 이동용 로봇은 Mamdani 형식의 퍼지 제어기로 제어 된다. 퍼지 제어기에 있어서 이동용 로봇과 목표 사이의 각도와 각도의 변화율이 입력으로 사용되고, 출력으로 조향각이 추론되어 제어입력이 된다. 퍼지 규칙은 전문가의 경험적 지식을 참조하여 7개를 사용하였다. 또한 퍼지 제어기 설계에 있어서 하나의 관심 분야인 환산계수(scaling factor) 조정 방법에 대해 제안한다. 본 논문에서는 이를 위해 파라미터 최적화 분야에서 잘 알려진 실수코딩 유전알고리즘을 적용하였다. 시뮬레이션을 통해 다양한 초기 조향각이 주어진 경우, 목표치에 대한 추적 안정성을 보여 퍼지 제어기의 유효성이 확인된다.

• 한국항해항만학회지
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• 제31권6호
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• pp.515-521
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• 2007

컨테이너 화물의 복합운송시스템 중에서 체화현상은 항만에서 가장 심각하다. 이러한 문제를 해결하기 위해 해상과 육상의 경계선에서 체선체화 문제를 발생시키는 컨테이너 크레인의 직업효율을 향상시키는 방법을 생각할 수 있다. 이를 위해 본 연구에서는 가능한 범위에서 트롤리를 목표지점까지 빠르게 이동시키는 동시에 목표위치에서의 흔들림도 짧은 시간 내에 제어하는 문제를 다루고 있다. 제어 전략으로 설계된 구간에서 최적의 성능과 강인성이 보장되는 LQ 제어와 제약조건에서 최적화가 가능한 실수코딩 유전알고리즘을 결합한다. 컴퓨터 시뮬레이션을 통해 제안한 제어기가 설정한 설계사양을 완벽하게 만족하는 것을 보임으로 그 유효성을 증명한다.