• Journal of the Korean Institute of Illuminating and Electrical Installation Engineers
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• v.28 no.2
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• pp.100-108
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• 2014

In this paper, an idea of a network type distributed control of a system with inner loop control structure will be considered. Generally, in case of a control system with inner loop control structure, it is not easy to implement circuits and programming. Using network type distributed control structure, it will show how it is better than before. CAN(Controller Area Network) protocol which has been known that it has a high reliability on the signal in the various network protocols is used. Also, Arago's Disk System which has a inner loop control stucture is made to validate effectiveness of the proposed method.

• Journal of the Korean Institute of Illuminating and Electrical Installation Engineers
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• v.29 no.1
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• pp.113-120
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• 2015

Network type distributed control system uses a communication line which is named the BUS to exchange a data among the sub-systems. Usually, on the bus, only one data must be exited at one time, so the control algorithm to prevent collision or to manage a priority of data is important. Including CAN Protocol, many kind of FieldBus which are used for distributed control system, prevent data collision by controlling transmission time. But, a system which have to make a control signal or get a data from a sensor at fixed time will be met a problem when it is composed by using a network type distributed control structure. In this paper, some of these cases will be discussed and solutions be proposed for preventing a data collision. Also, using Arago Disk System which have a structure for inner loop control, the validity of the proposed methods will be verified.

• Proceedings of the KIEE Conference
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• 2002.07d
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• pp.2292-2294
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• 2002

This paper presents the network of Distributed Control System(DCS) considering specification of nuclear power plant. The network is composed of field network, control network and information network. The protocol of control network is ring type and it is compared to ethernet type. This paper proposes the structure of DCS, the protocol of each network and analyzes the network traffic along data capacity of field network, control network, information network and the network performance. Network II.5 is used as traffic simulation tool.

• Journal of the Semiconductor & Display Technology
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• v.13 no.4
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• pp.37-42
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• 2014

Stable running is a very important factor when we are building a control system. But, sometimes malfunction of the system controller is caused by several reasons. To solve these problems, some systems have prepared a backup controller. In the generality of cases, making a backup controller is no easy work. Especially, it becomes more difficult when many backup controllers have to be embodied in one system. In this paper, the multi-backup function controller which was implemented in the form of the network type distributed control system will be suggested. Also, using Arago Disk System that has a structure for inner loop control, the validity of the proposed methods will be verified.

• 제어로봇시스템학회:학술대회논문집
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• 2003.10a
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• pp.1982-1985
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• 2003

Future cellular networks will mainly be driven by, high quality channels, high band with utilization, low power consumption and efficient network management. For a given channel allocation, the capacity and quality of communication of cellular radio systems using CDMA(Code Division Multiple Access) can be increased by using a transmitter power control scheme to combat the near-far problem. Centralized power control schemes or distributed ones to maximize the minimum signal-to-interference in each user of CDMA wireless network have been investigated. This paper has proposed a distributed power control algorithm, which employs an adaptive search scheme, in order to solve quickly the linear systems of equations for power update in CDMA cellular radio systems. The simulation results show that the proposed scheme has faster convergence rate than the typical bang-bang type of distributed power control algorithm, which has been much used as a reference algorithm in IS-95A and W-CDMA communication network.

• 제어로봇시스템학회:학술대회논문집
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• 2000.10a
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• pp.58-58
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• 2000

As many sensors and actuators are used in various automated systems, the application of network system to real-time distributed control is gaining acceptance in many industries. In order to take advantages of the network technique. however, network implementation should be carefully designed to satisfy real-time constraints and to consider network delays. This paper presents the implementation of feedback control system in Profibus-DP. Profibus-DP is a type of fieldbus protocols that are specifically designed to interconnect simple devices with fast I/O data exchange. As feedback control in profibus-DP is implemented, Network delays is found with influence of system performance. We analyze network delays in Profibus-DP into 3 reasons - dead time in Profibus interface, protocol delay, delay by asynchronization. In order to compensate the network delays, we introduce control algorithms with time delay concept. The results show that network delay can be compensated.

• Proceedings of the KIEE Conference
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• 2004.05a
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• pp.77-79
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• 2004

Because robot hardware architecture generally is consisted of a few sensors and motors connected to the central processing unit, this type of structure is led to time consuming and unreliable system. For analysis, one of the fundamental difficulties in real-time system is how to be bounded the time behavior of the system. When a distributed control network controls the robot, with a central computing hub that sets the goals for the robot, processes the sensor information and provides coordination targets for the joints. If the distributed system supposed to be connected to a control network, the joints have their own control processors that act in groups to maintain global stability, while also operating individually to provide local motor control. We try to analyze the architecture of network-based humanoid robot's leg part and deal with its application using the CAN(Controller Area Network) protocol.

• Proceedings of the KIEE Conference
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• 2006.04a
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• pp.195-197
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• 2006

In this paper, an interface unit is designed to efficiently monitor transmission data in Controller Area Network(CAN)-based control systems. The CAN uses a serial multi master communication protocol that efficiently supports distributed real-time control with a very high level of data integrity, and communication speeds of up to 1Mbps. The interface unit is composed of a DSP controller which collects data on the CAN bus and transfers data to a personal computer via serial communication to save and display of interesting signals. The experimental system consists of three DSP controllers which represent electronic control units of a vehicle, an interface unit for analysing the data on the bus, and a graphic monitoring program coded on the Windows platform. The validity and the effectiveness of the proposed simple type of CAN interface unit are shown through the experimental results.

• Journal of Power Electronics
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• v.16 no.2
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• pp.731-747
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• 2016

The droop-based control strategy is widely applied in the interfacing inverters for distributed generation. This can be a problem since low-frequency stability issues may be encountered in droop-based microgrid. The objective of this paper is to classify, evaluate and compare various low-frequency damping methods. First, low-frequency stability problems are analyzed and an equivalent model of a droop-controlled inverter is investigated to classify the damping methods into the source-type damping strategies and the impedance-type damping strategies. Moreover, the lead-lag compensation network insertion control is proposed as a beneficial part of the source-type damping strategies. Then, the advantages and disadvantages of the different types of damping methods are theoretically evaluated and experimentally tested. Furthermore, the damping methods are comprehensively compared to illustrate the application field of each method. Finally, the synthesis of different damping methods to enhance the low-frequency stability is discussed and experimental validation is presented.

• KSII Transactions on Internet and Information Systems (TIIS)
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• v.13 no.7
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• pp.3671-3689
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• 2019

Software defined networking brings unique security risks such as control plane saturation attack while enhancing the performance of wireless sensor networks. The attack is a new type of distributed denial of service (DDoS) attack, which is easy to launch. However, it is difficult to detect and hard to defend. In response to this, the attack threat model is discussed firstly, and then a DDoS attack prevention extension, called FuzzyGuard, is proposed. In FuzzyGuard, a control network with both the protection of data flow and the convergence of attack flow is constructed in the data plane by using the idea of independent routing control flow. Then, the attack detection is implemented by fuzzy inference method to output the current security state of the network. Different probabilistic suppression modes are adopted subsequently to deal with the attack flow to cost-effectively reduce the impact of the attack on the network. The prototype is implemented on SDN-WISE and the simulation experiment is carried out. The evaluation results show that FuzzyGuard could effectively protect the normal forwarding of data flow in the attacked state and has a good defensive effect on the control plane saturation attack with lower resource requirements.