• 동력기계공학회지
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• 제17권5호
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• pp.86-93
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• 2013

This paper proposes the used of genetic algorithm for optimizing PI controller and describes the dynamic modeling simulation for the permanent magnet synchronous motor driven by simplified vector control with the aid of MATLAB-Simulink environment. Furthermore, three kinds of error criterion minimization, integral absolute error, integral square error, and integral time absolute error, are used as objective function in the genetic algorithm. The modeling procedures and simulation results are described and presented in this paper. Computer simulation results indicate that the genetic algorithm was able to optimize the PI controller and gives good control performance of the system. Moreover, simplified vector control on permanent magnet synchronous motor does not need to regulate the direct axis component current. This makes simplified vector control of the permanent magnet synchronous motor very useful for some special applications that need simple control structure and low cost performance.

• Journal of Magnetics
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• 제21권4호
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• pp.529-536
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• 2016

Magnetically suspended sensitive gyroscopes (MSSGs) provide an interesting alternative for achieving precious attitude angular measurement. To effectively reduce the measurement error caused by dynamic imbalance, this paper proposes a novel compensation method based on analysis and modeling of the error for a MSSG. Firstly, the angular velocity measurement principle of the MSSG is described. Then the analytical model of dynamic imbalance error has been established by solving the complex coefficient differential dynamic equations of the rotor. The generation mechanism and changing regularity of the dynamic imbalance error have been revealed. Next, a compensation method is designed to compensate the dynamic imbalance error and improve the measurement accuracy of the MSSG. The common issues caused by dynamic imbalance can be effectively resolved by the proposed method in gyroscopes with a levitating rotor. Comparative simulation results before and after compensation have verified the effectiveness and superiority of the proposed compensation method.

• 한국건축친환경설비학회 논문집
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• 제12권6호
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• pp.627-640
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• 2018

Submetering electricity consumption data enables more detail input of end use components, such as lighting, plug, HVAC, and occupancy in building energy modeling. However, such an modeling efforts and results are rarely tried and published in terms of the estimation accuracy of electricity demand. In this research, actual submetering data obtained from a university building is analyzed and provided for building energy modeling practice. As alternative modeling cases, conventional modeling method (Case-1), using reference schedule per building usage, and main metering data based modeling method (Case-2) are established. Detail efforts are added to derive prototypical schedules from the metered data by introducing variability index. The simulation results revealed that Case-1 showed the largest error as we can expect. And Case-2 showed comparative error relative to Case-3 in terms of total electricity estimation. But Case-2 showed about two times larger error in CV (RMSE) in lighting energy demand due to lack of End Use consumption information.

• 한국CDE학회논문집
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• 제14권1호
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• pp.18-24
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• 2009

This paper proposes an analytical method of evaluating the maximum error by modeling the exact tool path for the tool traverse singular region in five-axis machining. It is known that the NC data from the inverse kinematics transformation of 5-axis machining can generate singular positions where incoherent movements of the rotary axes can appear. These lead to unexpected errors and abrupt operations, resulting in scoring on the machined surface. To resolve this problem, previous methods have calculated several tool positions during a singular operation, using inverse kinematics equations to predict tool trajectory and approximate the maximum error. This type of numerical approach, configuring the tool trajectory, requires much computation time to obtain a sufficient number of tool positions in a region. We have derived an analytical equation for the tool trajectory in a singular area by modeling the tool operation into a linear and a nonlinear part that is a general form of the tool trajectory in the singular area and that is suitable for all types of five-axis machine tools. In addition, we have evaluated the maximum tool-path error exactly, using our analytical model. Our algorithm can be used to modify NC data, making the operation smoother and bringing any errors to within tolerance.

• 한국정밀공학회:학술대회논문집
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• 한국정밀공학회 2008년도 추계학술대회 논문집
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• pp.399-400
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• 2008

• 제어로봇시스템학회:학술대회논문집
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• 제어로봇시스템학회 1987년도 한국자동제어학술회의논문집; 한국과학기술대학, 충남; 16-17 Oct. 1987
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• pp.470-472
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• 1987

This paper deals with the continuous-discrete estimation problem using FIR filters and performs modeling error analyses of the FIR filters, compared to Kalman filter and the limited memory filters, via computer simulations. It is shown that, the less driving noise the system has, the better performance the FIR filter exhibits and that this characteristic appears rare distinctly in nonlinear system than in linear systems.

• 대한공간정보학회지
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• 제13권2호
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• pp.79-84
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• 2005

현재 위성영상 센서모형화의 정확도에 관한 연구는 자료의 전체적인 오차크기를 추정하는데 초점이 맞추어져 있다. 이러한 유형의 오차평가는 오차의 정량적인 크기만을 고려한 것으로 오차의 분포 특성을 해석할 수 없다는 한계점을 안고 있다. 위성영상 센서모형화 결과의 수치적 평가는 오차의 분포 특성의 부재로 위성영상 모형화 결과의 신뢰성이 떨어지게 된다. 본 연구를 통해 오차의 크기를 잘 표현할 수 있는 RMSE와 더불어 오차의 방향성 계수를 산정함으로써 오차의 분포 특성을 확인할 수 있었다. 또한 방향성 계수가 1에 가까울수록 특정 계통오차가 있으며 0에 가까울수록 우연오차가 있음을 확인 할 수 있어 오차의 방향성 분석을 통하여 오차를 감소시킬 수 있는 방안을 제시할 수 있었다.

• Membrane and Water Treatment
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• 제9권5호
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• pp.363-371
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• 2018

In this work, it was investigated the usability of artificial bee colony (ABC) and genetic algorithm (GA) in modeling adsorption of Co(II) onto drinking water treatment sludge (DWTS). DWTS, obtained as inevitable byproduct at the end of drinking water treatment stages, was used as an adsorbent without any physical or chemical pre-treatment in the adsorption experiments. Firstly, DWTS was characterized employing various analytical procedures such as elemental, FT-IR, SEM-EDS, XRD, XRF and TGA/DTA analysis. Then, adsorption experiments were carried out in a batch system and DWTS's Co(II) removal potential was modelled via ABC and GA methods considering the effects of certain experimental parameters (initial pH, contact time, initial Co(II) concentration, DWTS dosage) called as the input parameters. The accuracy of ABC and GA method was determined and these methods were applied to four different functions: quadratic, exponential, linear and power. Some statistical indices (sum square error, root mean square error, mean absolute error, average relative error, and determination coefficient) were used to evaluate the performance of these models. The ABC and GA method with quadratic forms obtained better prediction. As a result, it was shown ABC and GA can be used optimization of the regression function coefficients in modeling adsorption experiments.

• Journal of Astronomy and Space Sciences
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• 제26권3호
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• pp.317-328
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• 2009

위성의 상대운동 모델은 두 위성 사이의 상대적인 운동을 기술하며, 위성편대비행 연구의 기본이 된다. 이 연구에서는 선형 및 비선형 상대운동 모델들의 정확도를 산출하고 이를 비교 분석하였다. 우선 모델의 정확도를 나타내는 '모델링 오차 지수(Modeling Error Index)'를 정의하였다. 다양한 주위성 궤도의 이심률과 두 위성 사이의 거리에 대해 모델링 오차 지수를 계산하여, 여러 궤도환경에 따른 기존의 여러 가지 상대운동 모델들의 정확도를 산출하였다. 여러 가지 상대운동 방정식들의 모델링 오차 지수는 주위성의 이심률의 크기, J2 섭동 고려 여부, 위성들의 상대 거리의 크기에 따라 달라진다. 이 연구에서 사용한 상대운동 모델의 정확도는 편대비행 동역학모델의 오차를 나타내므로, 이 연구 결과를 이용해서 주어진 편대비행 임무에 알맞은 모델을 선택하는 것이 가능하다.

• 한국정밀공학회:학술대회논문집
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• 한국정밀공학회 2010년도 추계학술대회 논문집
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• pp.325-326
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• 2010