• Title/Summary/Keyword: Distributed real-time control system

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Design of a Communication Protocol for the Physical Layer of the Digital Control System (디지털제어시스템의 물리계층 통신 프로토콜 설계)

  • Lee, S.W.
    • Proceedings of the KIEE Conference
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    • 2000.07d
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    • pp.2419-2422
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    • 2000
  • A distributed real-time system that is being used now is usually divided into three level : higher level, middle level, and lower level. The higher level network is usually called an information network, the middle level is called a control network, and the lower level is called a field network or a divice network. This dissertation suggests and implements a middle level network which is called PICNET-NP (Plant Implementation and Control Network for Nuclear Power Plant). PICNET-NP is based partly on IEEE 802.4 token-passing bus access methed and partly on IEEE 802.3 physical layer. For this purpose a new interface, a physical layer service translater, is introduced. A control network using this method is implemented and applied to a distributed real-time system.

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Design md Implementation for the Remote Real Time Process Monitoring and Control System based on the JMF (JMF 기반의 실시간 원격 공정 감시 및 제어 시스템 설계 및 구현)

  • Kim, Sam-Ryong;Lim, In-Taek;Lee, Jeong-Bae
    • The KIPS Transactions:PartD
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    • v.11D no.2
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    • pp.453-460
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    • 2004
  • In this thesis, remote conveyor control and monitoring system is designed and Implemented for shoes production process based on Lego prototyping mechanism by using the I/O interface control board for the ISA Interface control board. A conveyor server for real time profess control is implemented based on RTLinux(Real-Time Linux) so that users deride priority of work. And device driver is implemented bated on the RTLinux. Through this system, real-time Client/server monitoring environments Is implemented and tested. And the JMF(Java Media Framework) based monitoring system was implemented and the total processing status war monitored.

A Study on the Distributed Real-time Mobile Robot System using TCP/IP and Linux (Linux와 TCP/IP를 이용한 분산 실시간 이동로봇 시스템 구현에 관한 연구)

  • 김주민;김홍렬;양광웅;김대원
    • Journal of Institute of Control, Robotics and Systems
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    • v.9 no.10
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    • pp.789-797
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    • 2003
  • An implementation scheme and some improvements are proposed to adopt public-licensed operating system, Linux and de-facto world-wide network standard, TCP/IP into the field of behavior-based autonomous mobile robots. To demonstrate the needs of scheme and the improvement, an analysis is performed on a server/client communication problem with real time Linux previously proposed, and another analysis is also performed on interactions among TCP/IP communications and the performance of Linux system using them. Implementation of behavior-based control architecture on real time Linux is proposed firstly. Revised task-scheduling schemes are proposed that can enhance the performance of server/client communication among local tasks on a Linux platform. A new method of TCP/IP packet flow handling is proposed that prioritizes TCP/IP software interrupts with aperiodic server mechanism as well. To evaluate the implementation scheme and the proposed improvements, performance enhancements are shown through some simulations.

Scheduling of Sporadic and Periodic Tasks and Messages with End-to-End Constraints

  • Kim, Hyoung-Yuk;Kim, Sang-Yong;Oh, Hoon;Park, Hong-Seong
    • 제어로봇시스템학회:학술대회논문집
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    • 2004.08a
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    • pp.747-752
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    • 2004
  • Researches about scheduling of the distributed real-time systems have been proposed. However, they have some weak points, not scheduling both sporadic and periodic tasks and messages or being unable to guaranteeing the end-to-end constraints due to omitting precedence relations between sporadic tasks. So this paper proposes a new scheduling method for distributed real-time systems consisting of sporadic and periodic tasks with precedence relations and sporadic and periodic messages, guaranteeing end-to-end constraints. The proposed method is based on a binary search-based period assignment algorithm, an end-to-end laxity-based priority assignment algorithm, and three kinds of schedulability analysis, node, network, and end-to-end schedulability analysis. In addition, this paper describes the application model of sporadic tasks with precedence constraints in a distributed real-time system, shows that existing scheduling methods such as Rate Monotonic (RM) scheduling are not proper to be applied to the system having sporadic tasks with precedence constraints, and proposes an end-to-end laxity-based priority assignment algorithm.

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Variance of waiting time in the priority scheme of token bus protocols (토큰버스 프로토콜의 우선순위기능에서 대시시간의 분산)

  • Hong, Seung-Ho
    • Journal of the Korean Institute of Telematics and Electronics A
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    • v.32A no.5
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    • pp.42-53
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    • 1995
  • Token bus protocols have been sidely accepted for Medium Access Control (MAC) in real-time networks such as those used in factory automation, distributed process control, nuclear power plant, aircraft and spacecraft. Token bus protocols provide timer-controlled priority mechanism, which offers multiple level of privilege of medium access to different type of traffic. This paper presents and approximate analytical model for the evaluation of variance of waiting time in the time-controlled proiority scheme of token bus protocols. Token bus system is assumed to be operated with singe-service discipline which is the practical case of real-time networks such as those used in distributed process control and factory automations. The approximate analytical model is validated by comparison with the simulation resuls.

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A Implementation of Distributed Microsystem for DC Servo using uC/OS-II (uC/OS-II를 이용한 DC 모터의 실시간 분산 시스템 제어)

  • Lee, Youn-Hee;Kim, Tae-Kang;Yi, Keon-Young
    • Proceedings of the KIEE Conference
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    • 2002.07d
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    • pp.2415-2417
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    • 2002
  • In this paper, we discuss about the real-time distributed system for the control of to motors using uCOS-II kernel. Real-time kernel needs to process the tasks for two motors in desired time to synchronize motion. We used both semaphore and message mail box for synchronization. In the previous study, we used step motors for the actuator of two axes robot, but could not draw a clear line because of motor resolution and synchronizing step pulse. To resolve the problem we rebuilt the transfer robot with DC motors and the dedicated position servor which had built in out lab. Moreover we developed the PC based graphic user interface for generating planar drawing image control. Experimental results also presented to show the proposed control system is useful.

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Distributed Model Predictive Formation Control of UGV Swarm Guaranteeing Collision Avoidance (충돌 회피가 보장된 분산화된 군집 UGV의 모델 예측 포메이션 제어)

  • Park, Seong-Chang;Lee, Seung-Mok
    • IEMEK Journal of Embedded Systems and Applications
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    • v.17 no.2
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    • pp.115-121
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    • 2022
  • This paper proposes a distributed model predictive formation control algorithm for a group of unmanned ground vehicles (UGVs) with guaranteeing collision avoidance between UGVs. Generally, the model predictive control based formation control has a disadvantage in that it takes a long time to compute control inputs when considering collision avoidance between UGVs. In this paper, in order to overcome this problem, the formation control algorithm is implemented in a distributed manner so that it could be individually controlled. Also, a collision-avoidance method considering real-time is proposed. The proposed formation control algorithm is implemented based on robot operating system (ROS), open source-based middleware. Through the various simulation tests, it is confirmed that the formation control of five UGVs is successfully performed while avoiding collisions between UGVs.

ADAPTIVE, REAL-TIME TRAFFIC CONTROL MANAGEMENT

  • Nakamiti, G.;Freitas, R.
    • International Journal of Automotive Technology
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    • v.3 no.3
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    • pp.89-94
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    • 2002
  • This paper presents an architecture for distributed control systems and its underlying methodological framework. Ideas and concepts of distributed systems, artificial intelligence, and soft computing are merged into a unique architecture to provide cooperation, flexibility, and adaptability required by knowledge processing in intelligent control systems. The distinguished features of the architecture include a local problem solving capability to handle the specific requirements of each part of the system, an evolutionary case-based mechanism to improve performance and optimize controls, the use of linguistic variables as means for information aggregation, and fuzzy set theory to provide local control. A distributed traffic control system application is discussed to provide the details of the architecture, and to emphasize its usefulness. The performance of the distributed control system is compared with conventional control approaches under a variety of traffic situations.

Design and Implementation of Real-Time Controllers of an Enhanced Distributed Control System with Embedded TM/TC (TM/TC를 탑재한 분산제어 시스템의 실시간 제어기 설계와 구현)

  • Kim, Jin-Tae;Park, In-Kap
    • Journal of IKEEE
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    • v.3 no.1 s.4
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    • pp.57-68
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    • 1999
  • DCS require a remote supervisory control that applies a various applications with a period of integrated EIC(electric instrument control) using distributed computer network. Until now, DCS has leaved something to be desired in guaranteeing real-time required in remote site plant. In this paper, each controller is designed by implementing the controller suiting with an wide area to enhance the hardware of existing PRS controller and GWS, RPS and SRS, for the efficiency of TM/TC system, Therefore, real-time emphasizes on the communication processing time, rate of system load analyzed and validity was evaluated for a each implemented controllers.

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Sensors Network and Security and Multimedia Enhancement

  • Woo, Seon-mi;Lee, Malrey
    • International Journal of Internet, Broadcasting and Communication
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    • v.8 no.1
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    • pp.64-68
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    • 2016
  • These fields are integrated to visualize and finalize the proposed development, in simulation environment. SCADA (supervisory control and data acquisition) systems and distributed control systems (DCSs) are widely deployed in all over the world, which are designed to control the industrial infrastructures, in real ways. To supervise and control the various parts of designed systems; trends to require a deep knowledge to understand the overall functional needs of industries, which could be a big challenge. Industrial field devices (or network sensors) are usually distributed in many locations and are controlled from centralized site (or main control center); the communication provides various signs of security issues. To handle these issues, the research contribution will twofold: a method using cryptography is deployed in critical systems for security purposes and overall transmission is controlled from main controller site. At controller site, multimedia components are employed to control the overall transmission graphically, such as system communication, bytes flows, security embedded parameters and others, by the means of multimedia technology.