• Bulletin of the Korean Space Science Society
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• 2010.04a
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• pp.31.2-31.2
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• 2010

편대비행 위성이 공동의 임무를 수행하기 위해서는 편대를 이루는 위성의 각기 다른 초기 오차와 다양한 외란 환경에서도 자세 동기화를 이룰 수 있는 기법이 필요하다. 이 연구에서는 편대비행위성의 자세 동기화를 위하여 비선형 시스템에 대한 준최적 제어기법인 SDRE(State-Dependent Riccati Equation)에 기반한 추적 제어기가 사용되었다. 반작용 휠이 포함된 위성의 자세 동역학이 SDRE 추적 제어기를 구성하는데 이용된다. 이를 Leader/Follower 편대비행 시스템에 적용하며, 기준 자세를 추적하는 Leader 위성의 자세를 Follower 위성이 추적하여 자세 동기화를 이룰 수 있다. MATLAB과 SIMULINK를 이용한 수치해석적 시뮬레이션으로 추적 제어기의 성능을 검증하였으며, 이에 대한 실시간 HIL(Hardware-In-the-Loop) 시뮬레이션이 수행되었다. 무중력 환경을 모사하는 에어베어링시스템과 세 개의 반작용 휠을 장착한 자세제어 HILS(Hardware-In-the-Loop Simulator)는 PC104 타입의 임베디드 컴퓨터에서 SIMULINK의 xPC Target을 이용한 실시간 시뮬레이션 환경을 제공하며, 이에 적용되는 SDRE 추적 제어기는 이산화되어 설계되었다. 또한 SDRE 추적 제어기에 대한 안정성을 보장하는 영역이 추정되어 위 추적 제어기가 위성 편대비행에 적합한 자세 동기화 기법임을 보였다.

• Journal of the Korean Society for Precision Engineering
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• v.22 no.4
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• pp.136-143
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• 2005

Open architecture controller (OAC) is well known technology in factory automation. To better understand the requirements of OAC, authors have discussed the OAC related topics with a number of control experts who represents different segments of the machining industry. There is no common concept that is accepted or used, however, the common ideas for OAC is the control system that is hardware independent, interchangeable, and easily scalable. This paper presents summary of the understaning and requirements of OAC. Based on the requirements of OAC, authors developed the software based PC-CNC. The main focus of the PC-CNC was on the user customization capability and open interface between control networks in manufacturing system. This paper introduces the developed PC-CNC briefly. In addition to introduction of the PC-CNC, to fill the gap between end users and vendors of OAC, this paper presents two applications using OAC. One is a remote monitoring system. The OPC (Ole for Process Control) standard interface was used to monitor the status of open architecture CNC across network. The other is the remote production management module for machine tools using standard database interface.

• Transactions of the Korean Society of Mechanical Engineers A
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• v.29 no.5 s.236
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• pp.698-706
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• 2005

Finish machining of a curved surface is often carried out by an NC system with curve interpolation in the field. This NURBS interpolation adopts a feedrate optimizing strategy based on both the geometrical information and dynamic properties. In case of a finish cut using a ball-end mill, the curve interpolator needs to take the machining process into account for more improved surface, while reducing the polishing time. In this study, the effect of low machinability at the bottom of a tool on surface roughness is also considered. A particular curve interpolation algorithm is proposed fur generating feedrate commands which are able to control the roughness of a curved surface. The simulation of the machined surface by the proposed algorithm was carried out, and experimental results are presented.

• Proceedings of the KSME Conference
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• 2003.04a
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• pp.1226-1233
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• 2003

Finish machining of a curved surface is often carried out by an NC system with curve interpolation in the field. This NURBS interpolation adopts a feedrate optimizing strategy based on both the geometrical information and dynamic properties. In case of a finish cut using a ball-end mill, the curve interpolator needs to take the machining process into account for more improved surface, while reducing the polishing time. In this study, the effect of low machinability at the bottom of a tool on surface roughness is also considered. A particular curve interpolation algorithm is proposed for generating feedrate commands which are able to control the roughness of a curved surface. The simulation of the machined surface by the proposed algorithm was carried out, and experimental results are presented.

• Proceedings of the Korean Society of Precision Engineering Conference
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• 2003.06a
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• pp.162-167
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• 2003

Finish machining of a curved surface is often carried out by an NC system with curve interpolation in the field. This NURBS interpolation adopts a feedrate optimizing strategy based on both the geometrical information and dynamic properties. In case of a finish cut using a ball-end mill. the curve interpolator needs to take the machining process into account for more improved surface, while reducing the polishing time. In this study, the effect of low machinability at the bottom of a tool on surface roughness is also considered. A particular curve interpolation algorithm is proposed for generating feedrate commands which are able to control the roughness of a curved surface. The simulation of the machined surface by the proposed algorithm was carried out, and experimental results are presented.