• 한국시뮬레이션학회논문지
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• 제16권2호
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• pp.37-44
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• 2007

EWMA(지수가중평균)을 사용한 제어 방법은 반도체 제조 공정의 런투런 제어 환경에서 사용되는 대표적인 제어 방법이다. EWMA 제어에서는 제어 모수 값의 선택이 제어 결과에 주된 영향을 미치기 때문에, 공정 상황에 적합한 제어 모수 값을 사용하는 것이 중요하다. 불안정적인 공정 상황에서는 변화하는 공정 상황에 적합한 값으로 EWMA 제어 모수를 동적으로 변경하면서 제어해 주는 것이 고정된 모수 값을 사용하는 EWMA 제어에 비해 효율적이다. 본 연구에서는 동적인 EWMA 제어 모수를 사용한 기존 연구들을 살펴보고 이들의 단점을 보완한 새로운 알고리즘을 제시하며, 시뮬레이션을 통해 우수한 수행 결과를 확인하였다.

• International Journal of Automotive Technology
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• 제5권2호
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• pp.135-144
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• 2004

In this paper, the model-matching control in the longitudinal autonomous driving system is investigated by vehicle dynamics simulation, which contains nonlinear subcomponents and simplified subcomponents. The design of the robust model-matching controller is performed by the characteristics of the 2 degrees of freedom controller, which is composed of the feedforward compensator and the feedback compensator. It makes the characteristics of tractive and brake force to be equivalent to the specific transfer function, which is suggested as the reference model. Mathematical models of vehicle dynamic analysis including the model-matching control are constructed for computer simulation. Then, simple examples on open-loop simulation without any controller and closed loop simulation with the model-matching controller are applied to check the validity of the robust controller. As the practical example, the autonomous driving system in the longitudinal direction is adopted. It is proved that the model-matching control is effective and adequate to the disturbances and the perturbations, which are shown in the responses of the change of a vehicle mass and a road gradient.

• 한국정밀공학회:학술대회논문집
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• 한국정밀공학회 2000년도 추계학술대회 논문집
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• pp.118-122
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• 2000

Recently, High accuracy and precision are required in various industrial field especially, semiconductor manufacturing apparatus, Ultra precision positioning apparatus, Information field and so on. Positioning technology is a very important one among them. For composition of this technology, the development of system with high speed and high resolution is needed. At start point and end position vibration must be repressed on this system for composition of position control. This vibration is arisen nose, is increased setting time, is reduced accuracy. Especially, repressed for the lead with high speed. The small actuator with high speed and high resolution is need to repression against this residual vibration. This actuator is, for example, piezo actuator, piezoelectric material that converting from electronic signal to mechanical force is adequate material, beacause of control of control to position and force. In this study, piezo electric material is used to actuator, ultra precision positioning apparatus with stage of hinge structure is designed, simulation is performed, control performance is tested by producing apparatus. For easy usage and stability in industrial field, we perform to simulation and to position control test by digital PID controller.

• 풍력에너지저널
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• 제15권1호
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• pp.60-68
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• 2024

In this study, a hardware-in-the-loop simulation (HILS) environment was established using MATLAB/Simulink to simulate and verify the power performance of a wind turbine. The target wind turbine was selected as the NREL 5 MW model, and modeling was performed based on the disclosed specifications. The HILS environment consists of a PC equipped with a MATLAB/Simulink program, a programmable logic controller (PLC) for uploading and linking control algorithms, and data acquisition (DAQ) equipment to manage wind turbine data input and output. The operation of the HILS environment was carried out as a procedure of operation (PC) of the target wind turbine modeled based on MATLAB/Simulink, data acquisition (PLC) of control algorithms, control command calculation (PLC), and control command input (PC). The simulation was performed using the HILS environment under turbulent wind conditions and compared with the simulation results performed under the same conditions in the HILS environment using the commercial program Bladed for performance verification. From the comparison, it was found that the dynamic simulation results of the Bladed HILS and the MATLAB HILS were close in power performances and the errors in the average values of rotor rotation speed and power generation between the two simulations were about 0.44 % and 3.3 %, respectively.

• Journal of Astronomy and Space Sciences
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• 제26권1호
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• pp.99-110
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• 2009

이 연구의 목적은 편대비행위성의 항법 및 궤도제어를 위한 실시간 Hardware-In-the-Loop(HIL) 시뮬레이션 테스트베드를 개발하는데 있다. HIL 시뮬레이션 테스트베드는 실제와 비슷한 하드웨어 환경을 구성하여 주어진 편대비행임무 요구조건에 따른 새로운 개념의 알고리즘을 테스트할 수 있는 시뮬레이터이다. HIL 시뮬레이션 테스트베드는 실제의 인공위성 시스템 인터페이스와 최대한 유사하게 설계되었으며 환경 컴퓨터, GPS 시뮬레이터, GPS 수신기, 비행제어 컴퓨터, 시각화 컴퓨터 등 총 5개의 독립적인 시스템으로 구성되어 있다. Spirent Communication사의 GSS6560 다중패널 RF 시뮬레이터와, (주)세트렉아이에서 제작한 우주용 GPS 수신기를 사용하여 실제와 유사한 GPS 관측데이터를 사용한다. GPS 수신기로부터 획득한 관측데이터는 비행제어 컴퓨터 시스템으로 전송되고 이를 통해 편대비행위성의 절대위치 및 상대위치결정을 수행하였다. 또한 이 결과를 바탕으로 비행제어 컴퓨터 시스템은 궤도조정에 필요한 제어값을 계산하여 환경 컴퓨터 시스템으로 전송한다. 이렇게 5개의 독립적인 시스템을 유기적으로 통합하여 폐순환반복(closed-loop) HIL 시뮬레이션 테스트베드를 설계하였다. 이 논문에서는 편대비행 위성의 항법 및 제어 알고리즘 테스트를 위한 실시간 HIL 시뮬레이션 테스트베드의 전반적인 구성방법과 세부적인 구성요소에 대해 설명하였다 저궤도 편대비행위성의 편대유지 임무에 대한 가상의 시나리오를 설정하여 위성 편대비행의 항법 및 궤도제어 알고리즘을 실험적으로 검증하였다.

• 제어로봇시스템학회논문지
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• 제20권12호
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• pp.1246-1251
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• 2014

This article presents an optimum yaw moment distribution scheme for a vehicle with electronic stability control (ESC) and active rear steering (ARS). After computing the control yaw moment in the yaw moment controller, it should be distributed into tire forces, generated by ESC and ARS. In this paper, yaw moment distribution is formulated as an optimization problem. New objective function is proposed to tune the relative magnitudes of the tire forces. Weighed pseudo-inverse control allocation (WPCA) is adopted to solve the problem. To check the effectiveness of the proposed scheme, simulation is performed on a vehicle simulation package, CarSim. From the simulation, the proposed optimum yaw moment distribution scheme is shown to effective for vehicle stability control.

• 제어로봇시스템학회논문지
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• 제15권8호
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• pp.792-797
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• 2009

This paper presents the evaluation of PID and fuzzy control logic for the lateral position control of a moving web in roll-to-roll (R2R) printed electronics. In addition, we report the implementation of computer simulation software that enables us to develop the control logic in a graphic user interface and to test the controller performance in 3D dynamic environment. A mathematical model of the web dynamics is described first to explain the lateral motion of a moving web. Based on the model, PID and fuzzy controllers are designed, and embedded in the simulation software. Under the simulation conditions for fabricating RFID antenna by R2R printing, the results indicate that the fuzzy controller shows a better performance and can be more suitable for R2R multi-layer printed electronics.

• 한국자동차공학회논문집
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• 제7권7호
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• pp.202-213
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• 1999

Adaptive Cruise Control (ACC) is one of key features on intelligent Transportation System(ITS). In ACC, the steering is done by a driver, but the engine throttle valve and the brake are controlled electronically. The relative velocity and distance from the preceeding vehicle are measured by radars or image processing units and relevant vehicular spacing is maintained in ACC control systems. In this study, vehicle longitudinal dynamics are modeled to simulate vehicle longitudinal maneuver and to design longtitudinal controllers for ACC vehicles. The control algorithm is designed based on the modeled vehicle longitudinal dynamics using a non-linear sliding mode control method. To verity the performance of the control algorithm, a real time numerical simulation program is developed on a Silicon Graphics workstation using C-language . A real time graphic program is alos develpe and integrated with the numerical simulation program.

• 여성건강간호학회지
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• 제18권3호
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• pp.180-189
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• 2012

Purpose: The purpose of this study was to evaluate the effects of clinical practice and simulation-based practice for obstetrical nursing in terms of self-efficacy, practice satisfaction, and practice stress. Methods: A non-equivalent control group post test design was used. The participants were 171 junior nursing students, 103 in the experimental group, and 68 in the control group. Simulation-based practice consisted of nursing assessment during labor, nursing assessment and intervention for normal and high risk mother, nursing education for mother and family during labor, and open lab. The experimental group participated in simulation-based practice for two days and the control group participated in clinical practice at delivery room for two weeks. Results: The experimental group showed higher level of self-efficacy (p= .043), practice satisfaction (p<.001) and practice stress (p=.003) compared to the control group. Conclusion: Simulation-based practice is an effective learning method for obstetrical nursing and can be used as the alternative for clinical practice. However, stress management strategies are needed for simulation-based practice.

• Child Health Nursing Research
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• 제21권4호
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• pp.293-301
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• 2015

Purpose: This study was done to analyze the effectiveness of simulation-based integrated practice program (maternal-child) on nursing knowledge, self-confidence, and clinical competence of nursing students. Methods: A nonequivalent control group pre-post experimental design was used to compare experimental and control group. The experimental group received the integrated simulation practice and the control group received a separate simulation for maternal care and for newborn care. Results: The experimental group who had the integrated simulation had significantly higher scores for self-efficacy on nursing handover (F=0.480 p=.012) and oxygen therapy in newborn care (F=3.262 p=.037), and for clinical competence (F=2.639, p<.001) and personal satisfaction with debriefing compared to the control group (F=2.179, p=.044). But the experimental group did not have significantly higher scores in nursing knowledge. Conclusions The results indicate that an integrated simulation practice is an effective practice method to improve self-confidence, clinical competence and satisfaction. Also this study had significance in providing a setting similar to the clinical situation.