• International Journal of Control, Automation, and Systems
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• 제5권2호
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• pp.128-137
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• 2007

A robust adaptive controller design for a class of Markovian jump parametric -strict-feedback systems is given. The disturbances considered herein include both uncertain nonlinearities and Wiener noises of unknown covariance. And they satisfy some bound-conditions. By using stochastic Lyapunov method in Markovian jump systems, a switching robust adaptive controller was obtained that guarantees global uniform ultimate boundedness of the closed-loop jump system.

• 한국진공학회지
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• 제12권4호
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• pp.207-213
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• 2003

중진공 국가표준기의 자동화를 위한 하드웨어 및 측정 프로그램 개발에 관한 연구를 수행하였다. 이 장치는 부피가 서로 다른 여러 개의 진공용기, 배기장치, 진공게이지, 온도계, 그리고 밸브 등 많은 부품들로 구성되어 있을 뿐만 아니라 복잡한 측정방법 때문에 자동화가 꼭 필요하다. 개발한 자동화 장치의 성능 평가를 위하여 진공용기의 부피율을 측정하고 용량형 격막식 진공게이지를 교정해 보았다.

• Journal of Power Electronics
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• 제19권5호
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• pp.1193-1202
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• 2019

A SMPMSM drive system is a typical nonlinear system with time-varying parameters and unmodeled dynamics. The speed outer loop and current inner loop control structures are coupled and coexist with various disturbances, which makes the speed control of SMPMSM drive systems challenging. First, an ultra-local model of a PMSM driving system is established online based on the algebraic estimation method of model-free control. Second, based on the backstepping control framework, model-free adaptive integral backstepping (MF-AIB) control is proposed. This scheme is applied to the permanent magnet synchronous motor (PMSM) drive system of an electric vehicle for the first time. The validity of the proposed control scheme is verified by system simulations and experimental results obtained from a SMPMSM drive system bench test.

• 시스템엔지니어링학술지
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• 제18권2호
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• pp.126-139
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• 2022

The need for synthetic automation is increasing in preparation for a gradual decrease in laboratory research manpower due to low birth rate and aging. In this study, the existing laboratory synthesis method is analyzed based on the systems engineering technique. Then, it led to the derivation of the system requirements for a fixed-based robot manipulator capable of recognition, decision and control. The robot is equipped with replaceable modular end-effectors and designed depending on the purpose and process of the synthesis. The robot with an end-effector was implemented as PoC(Proof-of-Concept), and the functions for pipetting automation was verified.

• 한국생산제조학회지
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• 제22권1호
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• pp.138-144
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• 2013

The automation technology for overlay welding is needed due to the occurrence of severe corrosion and abrasion on the surface of internal contact in different shape of fittings. In Korea, different shapes of fittings have been manufactured by using the imported equipment of overlay welding automation at some companies. Thus the research on the development of overlay welding automation system (in short, OWAS) for a large L-type tube is urgently needed. In this paper, the investigation is focused on the optimal design of a supporting base for the (currently developing) OWAS of large L-type tube. Specifically we assume that the base which supports the equipment during the process of overlay welding is loaded as self-weight in the direction of gravity through static analysis especially when it is rotated 180 degree on the OWAS. For optimal design of a supporting base for OWAS of large L-type tube, Solidworks(R) (for 3-dimensional modelling) and ANASYS Workbench(R) (for structural analysis) are incorporated so as to proceed an optimization routines based on Response Surface Method (RSM) and Design of Experiment (DOE). In more specific, DOE finds out major factors (or dimensions) of the supporting base by using MINITAB(R). Then the regression equations between design variables (the major factors of supporting base) and response variables (deformation, stress and safety factor for the supporting base), which will be resulted in by RSM, verify the major factors of DOE. In the next step, Central Composite Design (CCD) plans 20 simulations of ANASYS Workbench(R) and then figures out the optimal values of design variables which will be reflected on the manufacturing of supporting base. Finally welding experiment is conducted to figure out the influence of overlay welding quality in applying the optimized design values of supporting base to the actual OWAS.

• Journal of Power Electronics
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• 제15권2호
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• pp.455-468
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• 2015

A microgrid (MG) with integrated renewable energy resources can benefit both utility companies and customers. As a result, they are attracting a great deal of attention. The control of a MG is very important for the stable operation of a MG. The droop-control method is popular since it avoids circulating currents among the converters without using any critical communication between them. Traditional droop control methods have the drawback of an inherent trade-off between power sharing and voltage and frequency regulation. An adaptive droop control method is proposed, which can operate in both the island mode and the grid-connected mode. It can also ensure smooth switching between these two modes. Furthermore, the voltage and frequency of a MG can be restored by using the proposed droop controller. Meanwhile, the active power can be dispatched appropriately in both operating modes based on the capacity or running cost of the Distributed Generators (DGs). The global information (such as the average voltage and output active power of the MG and so on) required by the proposed droop control method to restore the voltage and frequency deviations can be acquired distributedly based on the Multi Agent System (MAS). Simulation studies in PSCAD demonstrate the effectiveness of the proposed control method.

• 정보처리학회논문지:소프트웨어 및 데이터공학
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• 제12권1호
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• pp.41-50
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• 2023

최근에 인공지능 기술발전과 더불어 코로나19 바이러스(COVID-19)가 장기화되면서 비대면 사회가 일상화되었고, 많은 기업들은 이에 대응하기 위한 디지털 트랜스포메이션과 인공지능 도입의 활성화를 촉진시키고 있으며 챗봇의 수요가 급격히 늘어났다. 또한 챗봇은 기존의 단순문의 대응에서 업무 트랜잭션 처리를 하기에 이르렀다. 하지만 기존 시스템과 연계를 위해 API를 개발해야하고 연계 하는데 많은 어려움이 발생하고 있어, 이를 해결하기 위해 RPA연계를 통한 하이브리드 챗봇을 구축하는 것이 점점 중요해지고 있으며, 최근 RPA와 챗봇의 결합이 많은 비즈니스 프로세스를 처리하는 효과적인 도구로 간주되고 있다. 그러나 연계사례 부족과 구축 방법을 찾아보기 힘들어 많은 어려움을 겪고 있다. 본 연구에서는 기존 선행연구 고찰과 하이퍼오토메이션 관점에서 Conversational UX인 챗봇과 Task Automation의 RPA를 연계한 하이브리드 챗봇 구축을 위한 방법을 실제 구현사례를 바탕으로 제시하여, 보다 쉽게 연계방법을 이해하고 구축할 수 있도록 하여 디지털 트랜스포메이션에 적극적으로 AI 챗봇을 활용할 수 있도록 하는데 시사점이 있다.

• Wind and Structures
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• 제36권2호
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• pp.121-131
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• 2023

Aiming at the problem that fatigue characteristics of metal roof rely on local physical tests and lacks the cyclic load sequence matching with regional climate, this paper proposed a method of constructing the fatigue load spectrum based on integration of wind load model, measured data of long-span metal roof and climate statistical data. According to the turbulence characteristics of wind, the wind load model is established from the aspects of turbulence intensity, power spectral density and wind pressure coefficient. Considering the influence of roof configuration on wind pressure distribution, the parameters are modified through fusing the measured data with least squares method to approximate the actual wind pressure load of the roof system. Furthermore, with regards to the wind climate characteristics of building location, Weibull model is adopted to analyze the regional meteorological data to obtain the probability density distribution of wind velocity used for calculating wind load, so as to establish the cyclic wind load sequence with the attributes of regional climate and building configuration. Finally, taking a workshop's metal roof as an example, the wind load spectrum is constructed according to this method, and the fatigue simulation and residual life prediction are implemented based on the experimental data. The forecasting result is lightly higher than the design standards, consistent with general principles of its conservative safety design scale, which shows that the presented method is validated for the fatigue characteristics study and health assessment of metal roof.

• International Journal of Control, Automation, and Systems
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• 제5권6호
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• pp.707-711
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• 2007

An observer-based fault tolerant control (FTC) method is proposed for constrained switched systems (CSS) with input constraints. A family of Lyapunov-based bounded controllers are designed to ensure that, whenever actuator faults occur at the dwell time period of each continuous mode, the mode is always within its corresponding stability region. A set of switching laws are designed to guarantee the asymptotic stability of the overall CSS. The fixed stability regions on which the FTC method is based are also relaxed by the proposed variable stability regions. An example of CPU processing illustrates the effectiveness of proposed method.

• 한국정보통신학회논문지
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• 제7권4호
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• pp.779-787
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• 2003

최근에는 웹(Web)을 기반으로 하여 여러 분야에 적용되는 원격 감시, 자동화 제어 시스템 등의 개발에 관한 연구가 활발히 전개되고 있다. 본 논문에서는 기존의 자동화 시스템에 원격 제어 기술을 추가하였다. 오류의 수정과 적용이 쉬운 LabView 그래픽컬 언어를 사용하여 멀티미디어 데이터 처리, 일반적인 통신망(TCP/IP)상의 확장성을 고려한 실시간 모니터링 및 원격 제어를 위한 방법을 제안하고, 온실 환경 제어 시스템에 적용하였다. 적용 결과는 온실의 제어 상황을 원격으로 제어 및 감시하는데 매우 효율적인 것으로 평가되었다.