• 한국자동차공학회논문집
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• 제12권2호
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• pp.139-147
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• 2004

The purpose of engine control TCS is to regulate engine torque to keep driven wheel slip in a desired range. In this paper, engine control TCS using sliding mode control law based on engine model and estimated load torque is proposed. This system includes a two-level controller. Slip controller calculates desired wheel torque, and engine torque controller determines throttle angle for engine torque corresponding to desired wheel torque. Another issue is to measure load torque for model based controller design. Luenberger observer with state variables of load torque and engine speed solves this problem as estimating load torque. The performance of controller and observer is certificated by simulation using 8-degree vehicle model, Pacejka tire model, and 2-state engine model. The simulation results in various maneuvers during slippery and split road conditions showed that acceleration performance and ability of the vehicle with TCS is improved. Also, the load torque observer could estimate real load torque very well, so its performance was proved.

• 대한기계학회논문집A
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• 제28권8호
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• pp.1152-1158
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• 2004

In this study a MRAC(model reference adaptive control) for fluid power elevator model system was designed. The MRAC was compared with PI control in case of applying to the elevator model system with constant external load and changing external load. In this case external load was produced by a single fluid power cylinder combined with pressure control valve. In conclusion the MRAC control performance was better than PI control performance because overshoot and steady state error of the elevator model system controlled by the MRAC were not appeared for constant and changing external load.

• 전자공학회논문지SC
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• 제47권2호
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• pp.55-59
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• 2010

현재 움직이는 물체의 운동을 제어하기 위해 하중이라는 개념의 사용이 시도되고 있다. 하중이라는 제어 개념으로 불확실성으로 인한 비선형성을 포함한 시스템에서 보다 신뢰성 있는 제어값을 찾기 위해, 기존의 선형화 방법에 의한 상태방정식에서 제어값을 찾는 문제와 달리 비선형 하중 모델에서 직접 제어 값을 찾는 방법이다. 본 논문에서는 동력이 없고 제어되지 않는 자유 낙하 물체를 비선형 하중모델로 구현해보고, 외란에 따라 낙하하는 물체에 작용하는 하중값을 분석해 본다. 또한 이러한 외란에 의해 발생한 하중값에 따른 낙하 경로를 구한다. 본 논문의 연구결과는 비선형 모델 예측 제어 시스템에 적용하여 다 연장로켓, 추진력을 갖지 않은 GPS 유도탄 그리고 우주비행체의 지상귀환 제어시스템의 정밀도 향상을 위해 이용될 수 있다.

• 대한전기학회논문지:전력기술부문A
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• 제51권9호
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• pp.417-424
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• 2002

This paper presents an industrial peak load management system for the peak demand control. Kohonen neural network and wavelet transform based techniques are adopted for industrial peak load forecasting that will be used as input data of the peak demand control. Firstly, one year of historical load data of a steel company were sorted and clustered into several groups using Kohonen neural network and then wavelet transforms are applied with Biorthogonal 1.3 mother wavelet in order to forecast the peak load of one minute ahead. In addition, for the peak demand control, composite fuzzy model is proposed and implemented in this work. The results are compared with those of conventional model, fuzzy model and composite model, respectively. The outcome of the study clearly indicates that the composite fuzzy model approach can be used as an attractive and effective means of the peak demand control.

• 제어로봇시스템학회논문지
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• 제14권2호
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• pp.111-117
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• 2008

This paper presents a new continuation-based quasi-steady-state(CQSS) time-domain simulation algorithm incorporating a multiplicative aggregated load model for power systems. The authors' previous paper introduced a CQSS algorithm, which has the robust convergent characteristic near the singularity point due to the application of a continuation method. The previous CQSS algorithm implemented the load restoration in power systems using the exponent-based load recovery model that is derived from the additive dynamic load model. However, the reformulated exponent-based model causes the inappropriate variation of short-term load characteristics when switching actions occur, during time-domain simulation. This paper depicts how to incorporate a multiplicative load restoration model, which does not have the problem of deforming short-term load characteristics, into the time simulation algorithm, and shows an illustrative example with a 39-bus test system.

• 제어로봇시스템학회:학술대회논문집
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• 제어로봇시스템학회 2003년도 ICCAS
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• pp.1392-1397
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• 2003

This paper deals with a control technique of eliminating the transient vibration of a twin-drive geared mechanical system. This technique is based on a model-based control in order to establish the damping effect at the driven machine part. The control model is composed of reduced-order electrical and mechanical parts. This control model estimates a load speed converted to the motor shaft. The difference between the estimated load speed and the motor speed is calculated dynamically and it is added to the velocity command to suppress the transient vibration generated at the load. This control technique is applied to a twin-drive geared system with backlash. In the previous work, the performance of this control method is examined by simulations. In this paper, the effectiveness of this control technique is verified by experiments. The settling time of the residual vibration generated at the loading inertia can be shortened down to about 1/2 of the uncompensated vibration level.

• 전자공학회논문지SC
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• 제47권3호
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• pp.63-70
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• 2010

단진자 운동의 분석은 일반적으로 분석하며, 분석 결과는 자료에서 찾아볼 수가 있다. 일반적으로 단진자 운동의 해석은 뉴턴 제2법칙에 의해 선형화된 모델에서 속도, 주기, 시간에 따른 각도등이 계산된다. 본 논문에서는 단진자 운동을 비선형 하중제어 모델로 구현해 진자의 주기 운동을 해석한다. 즉 운동하는 진자의 위치에 따라 실시간으로 변화하는 하중을 분석해본다. 그리고 운동하는 진자의 위치 제어를 위해 필요한 하중 제어 값을 찾아보고, 마지막으로 선형화된 모델에서 구해진 값과 비선형 모델에서 구해진 값과 비교한다. 이와 같이 진자의 운동 및 비행체를 포함한 운동하는 물체를 제어하기 위해 비선형 하중제어 모델이 다양하게 적용될 수 있음을 나타낸다.

• Journal of Power Electronics
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• 제19권2호
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• pp.497-508
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• 2019

The predictive speed control (PSC) strategy can realize the simultaneous control of speed and current by using one cost function. As a model-based control method, the performance of the PSC is vulnerable to model mismatches such as load torque disturbances and parameter uncertainties. To solve this problem, this paper presents a robust predictive speed control (RPSC) strategy for surface-mounted permanent magnet synchronous motor (SPMSM) drives. The proposed RPSC uses extended state observers (ESOs) to estimate the lumped disturbances caused by load torque changes and parameter mismatches. The observer-based prediction model is then compensated by using the estimated disturbances. The introduction of ESOs can achieve robustness against predictive model uncertainties. In addition, a modified cost function is designed to further suppress load torque disturbances. The performance of the proposed RPSC scheme has been corroborated by experimental results under the condition of load torque changes and parameter mismatches.

• Educational Technology International
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• 제10권2호
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• pp.145-166
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• 2009

The purpose of this study was to investigate why advance organizers (AO) are effective in promoting comprehension and mental model formation in terms of cognitive load. Two experimental groups: a concept-map AO group and a key-word AO group and one control group were used. This study considered cognitive load in view of Baddeley's working memory model: central executive (CE), phonological loop (PL), and visuo-spatial sketch pad (VSSP). The present experiment directly examined cognitive load using dual task methodology. The results were as follows: central executive (CE) suppression task achievement for the concept map AO group was higher than the key word AO group and control group. Comprehension and mental model construction for the concept map AO group were higher than the other groups. These results indicated that the superiority of concept map AO owing to CE load decrement occurred with comprehension and mental model construction in learning. Thus, the available resources produced by CE load reduction may have been invested for comprehension and mental model construction of learning contents.

• 전자공학회논문지SC
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• 제47권4호
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• pp.61-68
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• 2010

최첨단 항공 기술을 3차원 공간이 아닌 평면에서 움직이는 자동차에 적용하므로써, 미래자동차의 가장 큰 목표인 "안전성"을 크게 향상시킬 수 있으며, 무인 자율 자동차 개발에 한발 더 다가갈 수 있다. 이것은 디지털 비행제어시스템에서 항공기의 운동 역학 모델이 구현되어, 자율 비행이 가능하도록 제어값이 찾아지므로 이루어진다. 이러한 첨단 항공 기술을 평면상에서 운동하는 자동차에 적용한다면, 무인 항공기와 같이 자율 운행할 수 있도록 제어 될 수 있을 것이다. 본 논문에서는 첨단 항공기의 비행 제어 시스템 모델로 사용되는 하중 제어 모델을 자동차에 적용하여 자동차의 운동 역학을 재해석하고, 하중제어 모델에서 자동차 움직임에 따른 승차감 분석을 한다. 또한 승차감 상향을 위한 해결 방법을 제시한다. 그리고 자동차의 자율 주행, 차선 변경 및 지능형 제동 시스템을 구현하기 위한 하중 제어 모델의 사용 예를 제시한다.