• 조명전기설비학회논문지
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• 제26권10호
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• pp.60-71
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• 2012

This paper proposes a new design and implementation of multi-protocol IED for networked control system of multi-induction motor in industrial fields. The experimental multi-induction motor based multi-protocol IED of Modbus/LonTalks/TCP/IP module is designed and fabricated. This article addresses issues in architecture of LonWorks/Ethernet sever, embedded processors architecture for converting Modbus protocol to LonTalks protocol, integrating preconfigured software, and Internet technologies. It is also verified that the multi-induction motor control and monitoring system using LonWorks/Ethernet server have available, interoperable, reliable performance characteristics from the experimental results, especially, the seamless integration of TCP/IP networks with control networks allows access to any control point from anywhere. Thus, the results provide available technical data for remote distributed motor control system of industrial field or building microgrid with LonWorks BAS.

• International Journal of Control, Automation, and Systems
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• 제5권4호
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• pp.372-378
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• 2007

This paper discusses Robust $H{\infty}$ control problems for networked control systems (NCSs) with time delays and subject to norm-bounded parameter uncertainties. Based on a new discrete-time model, two approaches of robust controller design are proposed. A numerical example and experimental verification with an NCS test bed are given to illustrate the feasibility and effectiveness of proposed design methodologies.

• 대한전기학회:학술대회논문집
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• 대한전기학회 2004년도 학술대회 논문집 정보 및 제어부문
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• pp.684-686
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• 2004

This paper is concerned with the DC motor speed control using distributed control system. We design CAN nodes which can transmit control and monitoring data through CAN bus and apply these to distributed networked control system. The results of the experiment validate effectiveness of our distributed networked control system.

• 전기학회논문지
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• 제62권5호
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• pp.688-695
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• 2013

Networked Control Systems(NCS) contain the structure which controllers, actuators and sensors are connected to communication network. And they have been adopted in large and complicated plant area due to the advantages of mitigating computational bottleneck and maintenance. Although this structure provides many benefits, it brings in problems of unpredictable communication delay, data loss and corruption. This phenomena have to be considered in designing NCSs since it affects on overall control system stability. This paper introduces network traffic test method for ethernet based NCSs to find out maximum network usage which guarantee stable control operation. Test results shows this methods can be adopted in various types of NCSs and contributes economical system design and effective system operation.

• 대한전기학회:학술대회논문집
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• 대한전기학회 2004년도 심포지엄 논문집 정보 및 제어부문
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• pp.38-40
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• 2004

An $H_2$ servo controller is proposed for networked control systems. The network-induced delay is assumed to be time-varying and vary in the known range. The proposed controller guarantees stability and $H_2$ performance for all time-varying delay in the known range. The proposed controller is verified using a simple networked motor control system.

• International journal of advanced smart convergence
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• 제5권1호
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• pp.34-46
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• 2016

Networked Control System (NCS) has evolved in the past decade through the advances in communication technology. The problems involved in NCS are broadly classified into two categories namely network issues due to network and control performance due to system network. The network problems are related to bandwidth allocation, scheduling and network security, and the control problems deal with stability analysis and delay compensation. Various delays with variable length occur due to sharing a common network medium. Though most delays are very less and mostly neglected, the network induced delay is significant. It occurs when sensors, actuators, and controllers exchange data packet across the communication network. Networked induced delay arises from sensor to controller and controller to actuator. This paper presents an adaptive delay compensation process for efficient control. Though Smith predictor has been commonly used as dead time compensators, it is not adaptive to match with the stochastic behavior of network characteristics. Time delay adaptive compensation gives an effective control to solve dead time, and creates a virtual environment using the plant model and computed delay which is used to compensate the effect of delay. This approach is simulated using TrueTime simulator that is a Matlab Simulink based simulator facilitates co-simulation of controller task execution in real-time kernels, network transmissions and continuous plant dynamics for NCS. The simulation result is analyzed, and it is confirmed that this control provides good performance.

• 전기전자학회논문지
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• 제23권3호
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• pp.899-903
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• 2019

네트워크 제어 시스템에서는 송신 신호의 시간 변동 지연이 불가피하다. 전송 지연이 고정된 샘플링 시간보다 길면 시스템이 불안정해진다. 이 문제를 해결하기 위해 본 논문은 논리 기반의 퍼지 신경망을 이용하여 지연을 예측하는 방법을 제안하며, 예측된 시간 지연은 네트워크 제어 시스템의 샘플링 시간으로 사용된다. 제안된 방법의 효과를 검증하기 위해, 실제 시스템에서 수집된 지연 데이터를 사용하여 논리 기반 퍼지 신경 네트워크를 훈련하고 테스트한다.

• 제어로봇시스템학회논문지
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• 제18권11호
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• pp.1040-1044
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• 2012

We design a NCS (Networked Control System) where the communication between sensors and controllers takes place over a USN (Ubiquitous Sensor Network). In order to measure time delays between sensors and controllers in real time, we design an algorithm to measure RTT (Round Trip Time) between USN nodes, and implement it into TinyOS of USN. By using the measured time delays, we construct the Smith predictor to compensate the time delays between sensors and controllers in real-time. For the real time experiment, we simulate the dynamic plant model, controller, and USN interface using Real-Time Windows Target provided in MATLAB. The USN interface in the Simulink model consists of serial ports, which connect the plant output and controller with USN nodes. The experiment results show that the time delays between sensors and controllers are precisely measured in real time; the Smith predictor appropriately compensates the time delays; and the stability is achieved in the closed-loop of the NCS.

• 제어로봇시스템학회논문지
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• 제17권11호
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• pp.1067-1073
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• 2011

In this paper, the methodology of a CA (Control Allocation) based FTNCS (Fault-Tolerant Networked Control System) is proposed. Control allocation is a control surface management technique by redistributing the redundant control surfaces in overactuated systems. In modern high performance aircrafts, they adopt many redundant control surfaces to provide high performance and to satisfy various tactical requirements. Moreover, redundant control surfaces provide an opportunity to compensate performance degradation due to failures in more than one actuator by re-allocating redundant control surfaces. Simulation results with an F-18 HARV demonstrate that the proposed CA based FTNCS can achieve a fast and accurate tracking performance even in the presence of actuator faults.

• 대한임베디드공학회논문지
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• 제6권3호
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• pp.149-156
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• 2011

Transmission delay and packet loss induced by a communication network can degrade the control performance and, even make the system unstable. This paper presents a method for compensating transmission delay and packet loss in a networked control system for unmanned underwater vehicle. The proposed method is based on Lagrange interpolation in order to satisfy the requirements of simplicity and model-independency. In this work, the lost/delayed data are estimated in real time by only using the past data without requiring any mathematical model of the controlled system. Consequently, the proposed method can be implemented independent of the controlled system, and also it can achieve fast and accurate compensation performance. The performance of the proposed technique is evaluated by numerical simulations with an unmanned underwater vehicle.