• Journal of Mechanical Science and Technology
• /
• 제17권4호
• /
• pp.484-491
• /
• 2003

For most of linear time-varying (LTV) systems, it is difficult to design time-varying controllers in analytic way. Accordingly, by approximating LTV systems as uncertain linear time-invariant, control design approaches such as robust control have been applied to the resulting uncertain LTI systems. In particular, a robust control method such as quantitative feedback theory (QFT) has an advantage of guaranteeing the frozen-time stability and the performance specification against plant parameter uncertainties. However, if these methods are applied to the approximated linear. time-invariant (LTI) plants with large uncertainty, the resulting control law becomes complicated and also may not become ineffective with faster dynamic behavior. In this paper, as a method to enhance the fast dynamic performance of LTV systems with bounded time-varying parameters, the approximated uncertainty of time-varying parameters are reduced by the proposed QFT parameter-scheduling control design based on radial basis function (RBF) networks.

• Journal of Biosystems Engineering
• /
• 제29권5호
• /
• pp.425-432
• /
• 2004

In harvesting rice and barley using combine, the inclination of the body caused by the irregular surface condition of the field and the soil sinking from the unbalanced weight during the grain collection used to make harvesting operation difficult and even impossible. To overcome such a problem hydraulic system far automatic and manual leveling control of a combine has been developed. The system was composed of the combine body and the hydraulic level control system mounted on it. The maximum height of ground clearance was set up to be 290mm. And the limit angle of the leveling control was set up to be $\pm7^{\circ}$. The proposed controller and hydraulic system was implemented to the prototype combine. The prototype combine was designed and built as a separable structure with the body and the track of it. This paper shows results of a specification and design testing with the hydraulic level control system far body of combine.

• International Journal of Precision Engineering and Manufacturing
• /
• 제5권2호
• /
• pp.22-31
• /
• 2004

A problem of task rescheduling using a coordinator in a structural decentralized control of supervisory control theory is formulated. we consider that the overall system is divided into a number of local systems. Using an example of a chemical batch reaction process, it has shown that after local supervisors have been established for a given task, a coordinator can be used to solve some rescheduling problems among local plants for new or modified tasks. The coordination system models the interactions of local plants, and is consisting of only the shared events of local plants, so simpler to synthesize. A coordinator is designed based on the specifications given for the coordination system. Under the 'structural' conditions developed in this paper, the combined concurrent actions of the coordinator with the existing local supervisors will achieve the rescheduling requirements. Again since the conditions are structural (not specification-dependent), once the coordination architecture has been established, it can be used for a number of different tasks without further verifications.

• 전기학회논문지
• /
• 제62권12호
• /
• pp.1777-1783
• /
• 2013

This study aims to implement an instrumentation system measuring and analysing real-time data of information flow between respective subunits composing train control system as the performance evaluation method for wireless communication based urban railway train control system under development for a Korean model. It analyses system functional requirements regarding subsystems composing wireless communication based train control system and test items for functions presented in each specification and examines data and measurement point for measuring according to test items in order to implement an instrumentation system. And, it clearly defines requirements of an instrumentation system to avoid malfunction or error in operation of train control system. It reviews data processing method and display method for effective analysis of data flow between respective subunits with measured data, designs and makes an instrumentation system. Ultimately, it applies to a performance test of train control system and makes sure an instrumentation system in normal working order.

• 한국산학기술학회논문지
• /
• 제10권4호
• /
• pp.753-758
• /
• 2009

LVDS에 기반을 둔 초고속 저전력 직렬 인터페이스인 SMIA(Standard Mobile Imaging Architecture) CCP2(Compact Camera Port 2) 규격을 채택한 CMOS 이미지 센서들이 개발되면서, 기존의 CMOS 이미지 센서들과 직접 연결되었던 장비들이 사용할 수 없게 되고 있다 본 논문에서는 SMIA CCP2 규격의 직렬데이터 신호를 범용 10-비트 병렬 신호로 변환하는 시스템을 제안하고. 이의 구현 방안을 제시한다. 제안한 데이터 프로토콜 변환 시스템은 de-serializer 1개와 저가의 FPGA로 구성되어 소형 PCB로 구현되어, 장비와 이미지 센서 사이를 추가 공간 없이 용이하게 접속할 수 있다. 또한 SMIA CCP2 규격에서 제시된 최대 속도인 650Mbps의 속도로 데이터를 변환하는 것이 가능하기 때문에 범용 프로토콜 변환 시스템으로서의 활용성도 매우 높을 것으로 기대된다.

• 한국전자파학회논문지
• /
• 제25권3호
• /
• pp.311-318
• /
• 2014

소형 위성 발사체 나로호의 전자파 적합성 성능은 탑재 위성과 우주센터에 설치되는 지상 장비, 그리고 다른 무선통신망 사이에서 정상적인 동작을 보장하도록 확보되고 검증되어야 한다. 전자파 적합성 성능을 검증하기 위해서는 서브 시스템과 시스템에 대한 적절한 시험 규격과 방법, 그리고 절차가 발사체의 운용 특성과 전자기 환경을 고려하여 수립되어야 한다. 그리고 프로그램 종료단계까지 결정된 규격에 따라 지속적으로 전자파 적합성 특성을 유지 관리하는 것이 요구된다. 본 논문에서는 나로호의 발사체 개발 전 주기 동안 수행된 순차적인 관리 업무를 기술하고, 나로호와 각 서브 시스템의 각 모델에 대한 단계별 시험계획뿐만 아니라, 시험 방법, 규격, 검증시험 결과 등이 제시된다. 또한, 멀티팩션 분석에 대한 결과를 기술한다.

• 한국철도학회:학술대회논문집
• /
• 한국철도학회 2009년도 춘계학술대회 논문집
• /
• pp.1229-1234
• /
• 2009

현재 한국철도공사에서 운행하는 철도차량은 KTX, 새마을호동차(PP), 선행전기기관차 (NEL), 전기기관차 (EL), 디첼기관차, 도시통근형동차(CDC), VVVF, 저항제어차 등 8 여종에 이르고, 현재는 150km/h 급 간선행전기동차 (Electric Multiple Unit)는 시험운행중이다. 또한 조만간 폐차되는 새마을호동차의 대체차량으로 180km/h 급 간선형전기동차의 도입이 예정되어 있다. 하지만 아직까지 철도차량의 운전실제어대 설계기준이 없고, 제어기기의 배치 및 형식 등에 대해 운전자의 입장에서 인체공학적 접근을 시도한 연구도 전무한 실정이어서 개발되는 차량마다 제어기의 형식 및 조작방식이 상이하다. 이는 운전자의 기기 취급 오류률 유발할 가능성이 매우 크며, 신규차량 도입시 별도의 운전자 교육을 시행해야하는 동 운영 상의 효율성이 매우 떨어진다. 따라서 운전자의 의견수렴을 바탕으로 운전 중 상시 취급하는 제어기기 및 안전설비에 대하여 안전공학 및 인체공학적 설계기준을 마련하여 운전자로 하여금 기기취급에 정확성을 높이고, 이례적인 상황에서 보다 더 신속한 대처를 할 수 있도록 하여 철도차량 안전성과 운영상의 효율성을 증진하고자 한다.

• 한국정보통신학회논문지
• /
• 제19권11호
• /
• pp.2751-2757
• /
• 2015

유도제어 시스템 체계 개발의 초기단계에는 운용 효과도 도출 및 요구사항 적합성 검토를 통한 체계 개략사양도출을 위해 효과도 분석을 수행한다. 본 논문에서는 M&S (Modeling & Simulation)를 활용하여 항법센서 성능과 환경영향(조류의 세기와 방향)에 따른 유도제어 시스템의 목표점 도달 정확도에 대한 운용 효과도 분석을 수행한다. 효과도 분석을 위해 6자유도 운동모델, 환경모델, 유도항법제어모델을 구성한다. 항법센서는 관성항법센서(Inertia Navigation Sensor, INS)와 도플러 속도센서(Doppler Velocity Log, DVL)로 구성하고, 환경변수는 조류(current)의 세기와 방향이다. 수치 시뮬레이션 결과는 CEP(Circular Error Probability)와 분산을 이용한 확률분석으로 분석한다. 효과도 분석 결과는 항법센서의 가격을 고려한 비용 대비 효율 분석에 활용하여 가격 대비 높은 성능의 센서 사양을 도출할 수 있다. 본 논문에서는 높은 수준의 INS와 낮은 수준의 DVL을 이용하면 가격 대비 성능이 높은 복합항법센서를 구성한다는 것을 보여준다.

• 제어로봇시스템학회:학술대회논문집
• /
• 제어로봇시스템학회 2003년도 ICCAS
• /
• pp.2164-2168
• /
• 2003

Real time control system such as in factory automation fields, defense field, aerospace, railway industries, financial trading and so forth, includes multiple computers on multiple nodes, and share data to process various actions and functions. This is similar to multitasking in a multiprocessor computer system. The task processing efficiency of such system is proportionally increased by process speed of each process computer. And also it is greatly influenced by communication latencies of each node. To provide proper operation of such real time system, a network that can guarantee deterministic exchange of certain amount of data within a limited time is required. Such network is called as a real time network. As for modern distributed control system, the timeliness of data exchange gives important factor for the dynamics of entire control system. In a real time network system, exchanged data are determined by off-line design process to provide the timeliness of data. In other word, designer of network makes up a network data table that describes the specification of data exchanged between control equipments. And by this off-line design result, the network data are exchanged by predetermined schedule. First, this paper explains international standard real time network TCN (Train Communication Network) applied to the KHST (Korean High Speed Train) project. And then it explains the computer program developed for design tool of network data table of TCN.

• 품질경영학회지
• /
• 제42권3호
• /
• pp.279-290
• /
• 2014

Purpose: The purpose of this study is to propose adoption of QFD and Stage-gate in order to analyze the quality of korea defense system. Methods: Drawing change data of initial production phase in korea defense system were anlayzed and a practical method was proposed. Results: The results of this study are as follows; Off line Quality Control should be introduced in development phase. Specially, in case of defense system, the best method is QFD(Quality Function Deployment) and Stage-gate process. At first, QFD 1 step defines product planning from VOC(Voice Of Customer), QFD 2 step specifies part planning from product planning, QFD 3 step defines process planning from part planning, QFD 4 step defines production planning from previous process planning. Secondly, Stage-gate process is adopted. This study is proposed 5 stage-gate in case of korea defense development. Gate 1 is located after SFR(System Function Review), Gate 2 is located after PDR(Preliminary Design Review), Gate 3 is located after CDR(Critical Design Review), Gate 4 is located after TRR(Test Readiness Review) and Gate 5 is located before specification documentation submission. Conclusion: Off line QC(Quality Control) in development phase is necessary prior to on line QC(Quality Control) in p roduction phase. For the purpose of off line quality control, QFD(Quality Function Deployment) and Stage-gate process can be adopted.