Real-time Distributed Control Systems Research Articles

A Human-Augmenting Resource/Performance Co-Design Tool for Real-Time Distributed Control Systems

A Human-Augmenting Resource/Performance Co-Design Tool for Real-Time Distributed Control Systems

Actuator Fault Tolerant Control of Variable Cycle Engine Using Sliding Mode Control Scheme

This paper presents a fault tolerant control (FTC) design for the actuator faults in a variable cycle engine (VCE). Ensured by the multiple variable geometries structure of VCE, the design is realized by distributing the control effort among the unfaulty actuators with the “functional redundancy” idea. The FTC design consists of two parts: the fault reconstruction part and the fault tolerant control part, which use a sliding mode observer (SMO) and a sliding mode control (SMC) scheme respectively. Considering the inaccuracy of the fault reconstruction result, the proposed design requires only inaccurate fault information. The stability of the closed-loop control system is proved and the existence condition for the proposed control law is analyzed. This work also reveals its relation to the sliding mode control allocation design and the adaptive SMC design. An application case is then studied for tolerating the loss of effectiveness fault of the nozzle area actuator. Results show that the FTC design is able to tolerate the fault and achieves the same control goal as in the fault-free situation. Finally, a hardware-in-the-loop test is carried out to verify the design in a real-time distributed control system, which demonstrates its use from the engineering perspective.

Modelling and Performance Analysis of a New Time-Triggered CAN FD Protocol for Real-time Distributed Control Systems

Modelling and Performance Analysis of a New Time-Triggered CAN FD Protocol for Real-time Distributed Control Systems

Performance Evaluation of DDS-Based Middleware over Wireless Channel for Reconfigurable Manufacturing Systems

Reconfigurable manufacturing systems (RMS) are rapidly becoming choice of production and manufacturing industry due to their quick adaptability to the ever-changing market demands while maintaining the quality and cost of the products. Such systems are usually decentralized in their monitoring and control and consist of heterogeneous components. Therefore, need arises for an interface that can mask the heterogeneity and provide smooth communication among these dissimilar components. Data Distribution Service (DDS) is a data-centric middleware standard based on Real-Time Publish/Subscribe (RTPS) protocol that fulfills the job of such interface in distributed systems. In this work, we present the idea of using DDS-based middleware over commonly used wireless channels like Bluetooth and Industrial WiFi to facilitate data communication in distributed control systems. A simulation model is developed to quantify various performance measures like latency, jitter, and throughput and to examine the suitability of aforementioned wireless channels in distributed monitoring and control environments. The model explores various communication scenarios based upon a practical case study. Obtained results serve as an empirical proof of concept that DDS can ensure reliable and timely data communication in firm real-time distributed control systems using common wireless channels and offer extensive control over various aspects of data transmission through its rich set of QoS policies.

Framework of Distributed Automated System Controlling Via Mobile Device

A daily used technology, mobile device such as smartphone has grown its popularity among consumer market and its wide market makes it a candidate for industrial application. Currently, there are no devices based solutions for real time distributed control system via smartphone especially in industrial automation domain. This research has been done on creating framework of distributed controlling via mobile device.

Providing services using network-based humanoids in a home environment

This paper describes the development of network based humanoids to provide services in the home environment. For successful service in more intelligent and varied environments, various robot sub-systems need to be coordinated effectively. Thus, this paper also introduces a coordinated framework which makes robot-human interaction while executing various tasks by means of various robots. Using a task script, an operator can easily describe tasks and regulate actions of the sub-systems while a robot is performing the task. Furthermore, the control system of a robot must operate efficiently to ensure a coordinated robot system, so the realization of an IEEE-1394 real-time distributed control system and a motor controller for a humanoid robot are introduced. Many algorithms have been developed, and the following technologies are described herein: autonomous biped walking; real-time modification of collision-free paths; and interaction ability with humans and environments, such as face, voice, or object recognition. The results of the demonstration show that humanoids can execute tasks efficiently and are suitable to provide services in human environments, such as restaurants or homes. <sup xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink">1</sup> .

Repetitive tracking position control on LonWorks/IP network with time varying delay

LonWorks over IP (LonWorks/IP) network is an integrated form of LonWorks device network and IP data network. LonWorks/IP network can offer ubiquitous access to the information on the factory floor and the real-time distributed control can be made possible. Timely response is inevitable for the real-time distributed control on the factory floor. Network induced uncertain time delay deteriorates the performance and stability of the real-time distributed control system on LonWorks/IP network. Therefore, time-varying uncertain time delay needs to be compensated for, in order to guarantee the stability and to improve the performance of the networked distributed control system. In this paper a control scheme based on disturbance observer and repetitive controller for the real-time distributed control on LonWorks/IP network with time-varying delay is proposed and tested through experiment. The result of the proposed control is compared with that of internal model controller (IMC) based on Smith predictor and disturbance observer. It is shown that the proposed control scheme can improve the tracking performance of the periodic reference.

Design patterns for real-time distributed control system benchmarking

In this paper, we describe the design and development of a simulation–agent interface for real-time distributed control system benchmarking. This work is motivated by the need to test the feasibility of extending agent-based systems to the physical device level in manufacturing and other industrial automation systems. Our work focuses on the development of hybrid physical/simulation environment that can be used to perform tests at both the physical device level, as well as the planning and scheduling level of control. As part of this work, we have extended the proxy design pattern for this application. This paper focuses on the resulting software design pattern for distributed control system benchmarking and provides examples of its use in our hybrid physical/simulation environment.

KSTAR 전류전송제어시스템의 원격운전을 위한 EPICS 기반 제어계 구축

KSTAR 전류전송제어시스템은 네트워크기반의 실시간 분산제어시스템으로 EPICS (Experimental Physics and Industrial Control System)를 미들웨어로 채용하여 구축하였다. 전류전송제어시스템은 초전도자석시스템에 전류를 전송하기 위한 시스템으로서 전류전송과 동시에 초전도자석이 초전도상태를 유지하기 위한 냉매의 전송도 담당하고 있다. 주제어실에서의 원격운전을 위하여 EPICS IOC(Input Output Controller) 서버를 현장에 설치하였고 이를 통하여 전류전송제어시스템은 고유의 이름(PV)에 적절한 조작 및 감시 명령을 부여하여 주제어실의 운전화면을 통하여 시스템의 감시 및 조작이 가능하도록 하였다. EPICS와 PLC의 통신을 위하여 ether-ip 드라이버를 이용하여 EPICS IOC를 구축하였으며, 시험 결과 안정성 및 운용성 측면에서 만족할 만한 결과를 획득하였다. The KSTAR Current Lead System(CLS) with network based real-time distributed control system is implemented using an EPICS as a middle-ware software. The current lead system transfers current from magnet power supplies to superconducting magnet system and simultaneously supply the coolant to maintain superconducting state. To control the CLS at main control room an EPICS IOC server is installed in local control area. Using this server, it is able to be controlled and monitored the system in main control room through operator interface(OPI) which uses "caget" to read status and "caput" to write command with a unique name called PV. The EPICS IOC is developed using "ether-ip" driver to communicate with PLC. Also we achieved satisfactory results in operation and stability aspects from a long period commissioning test.

The Real-Time Distributed Control of the Virgo Interferometric Detector of Gravitational Waves

<para xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink"> The VIRGO experiment for the detection of gravitational waves is a big challenge both for physics and for technology. In particular, to satisfy the stringent requirements on the alignment and position of its suspended optical components to keep the detector at its point, a very complex distributed and supervised control system has been implemented. The current constraints are about <formula formulatype="inline"><tex>$10 ^{-10}~ {\hbox {m}}$</tex></formula> RMS for the longitudinal control (“Locking'') and <formula formulatype="inline"> <tex>$10 ^{-9}~{\hbox {rad}}$</tex></formula> RMS for the angular degrees of freedom (“Alignment''). These requirements are satisfied by means of a specially designed hierarchical architecture for the local control system. It is necessary for managing the hard task of filtering all the environmental noises that limit the sensitivity of the interferometer. On the other end, the interferometer is supervised by a distributed global control system to maintain the detector fully operational. In this paper we describe the status of the real-time distributed control system of the Virgo interferometric detector of Gravitational waves, its performances and planned improvements. </para>

Estrategias de Enseñanza a Distancia sobre Control No-Lineal Aplicada al Péndulo Invertido

This paper presents a software/hardware tool to study, at university level, distributed control systems in real time. This platform is applied to control nonlinear processes. The system has three different parts which students can evaluate and modify; i) a virtual model represents the physic model of the inverted pendulum; the controller is implemented by a real time distributed control system; and iii) the whole system is managed with a JAVA application. Therefore, students have all the necessary elements to practice with complex nonlinear systems, such as the inverted pendulum discussed in this work. The tests done show that the plattform represents a fast and reliable method for experimentation by the students.

NONATTENDANCE EDUCATIONAL STRATEGIES FOR NONLINEAR CONTROL USING THE INVERTED PENDULUM

This paper presents a complete tool where students can study and test nonlinear control algorithms. The system has three different parts which students can evaluate and modify. First, a Simulink model represents the physic model. In this case the inverted pendulum is used. Second, the controller is implemented by a real time distributed control system. Finally, all the system can be managed with a JAVA application. Therefore, students have all the necessary elements to practise with nonlinear and complex systems.

Design and evaluation of real-time distributed manufacturing control systems

In this paper, we describe two general models for designing real-time distributed manufacturing control systems based on the IEC61499 (function block) standard. In order to construct IEC61499 function blocks, each model utilises UML capsules within an object-oriented framework. In the first model we treat a function block as a single capsule, while in the second we model the function block as a component containing multiple capsules. The key difference between these two viewpoints is the granularity of control we have over the function block's operation and its location within the decentralised manufacturing environment. We also evaluate the merits of these two viewpoints using a discrete-event simulation experimental test bed.

A hybrid environment for real-time distributed manufacturing control benchmarking

In this paper we propose a hybrid physical/simulation environment for benchmarking real-time distributed control systems that uses Arena Real Time for simulation and the Java-based TINI platform for real-time control. This system is intended to allow holonic- and agent-based systems to be evaluated across the entire manufacturing enterprise from planning and scheduling to real-time control. The paper provides an overview of the experimental system and reports on our preliminary results with a manufacturing benchmark. These results show that by incorporating actual physical devices in the simulation environment, effects that are often difficult to quantify such as communication latency and processor latency can be observed.

A HYBRID SIMULATION/PHYSICAL ENVIRONMENT FOR BENCHMARKING REAL-TIME DISTRIBUTED CONTROL SYSTEMS

In this paper we propose a hybrid physical/simulation environment for benchmarking real-time distributed control systems. This environment uses Arena® Real Time for simulation and the Java-based TINI platform for real-time control. Experimental results show that the characteristics of the physical device can be accounted for through the use of this hybrid environment.

An agent-based approach to reconfiguration of real-time distributed control systems

We describe a general approach for dynamic and intelligent reconfiguration of real-time distributed control systems that utilizes the IEC 61499 function block model. This work is central to the development of distributed intelligent control systems that are inherently adaptable and dynamically reconfigurable. The approach that is used takes advantage of distributed artificial intelligence at the planning and control levels to achieve significantly shorter up-front commissioning times as well as significantly more responsiveness to change. This approach is based on object-oriented and agent-based methods, and aims at overcoming the difficulties associated with managing real-time reconfiguration of an intelligent manufacturing system.

A reconfigurable concurrent function block model and its implementation in real-time Java

This paper focuses on the important holonic manufacturing systems issue of automatic and dynamic adaptability to change at the physical machine level of control. We propose a model to support configuration and reconfiguration of real-time distributed

인터넷과 CAN을 이용한 원격 분산 Embedded System 설계

A small size and light-weight DSP board is newly designed for a real time multi-distributed control system that overcomes constraints on time and space. There are a variety of protocols for a real-time distributed control system. In this research, we selected CAN for the multi distributed control, which was developed by the BOSCH in the early 1980's. If CAN and Internet are connected together, the system attains the characteristics of a distributed control system and a remote control system simultaneously. To build such a system. The TCP/IP-CAN Gateway which converts a CAN protocol to TCP/IP protocol and vice verse, was designed. Moreover, the system is required to be small and light-weighted for the high mobility and cost effectiveness. The equipment in remote place has a TCP/IP-CAN Gateway on itself to be able to communicate with another systems. The received commands in the remote site are converted from TCP/IP protocol to CAN protocol by the TCP/IP-CAN Gateway in real time. A simulation system consists of a TCP/IP-CAN Gateway in remote place and a command PC to be connected to Ethernet.

Static Task Allocation in Real-time Distributed Computer Control Systems

The task allocation problem consists in defining a space and time sharing of system resources that can meet all logical and operational constraints of the tasks being considered. For real-time tasks with predictable behavior (periodic), static allocation provides a reliable way to meet temporal scheduling requirements, together with other operational constraints, such as task replication for fault-tolerance. Unfortunately, finding an optimal feasible allocation is known to be NP-hard, and thus heuristic approaches have been proposed. In this paper, the use of a new heuristic to generate static allocations for critical periodic tasks in real-time distributed control systems is described.

Knowledge-based supervision and control of wastewater treatment plant: a real-time implementation

The hardware architecture and the software development of a real-time knowledge-based distributed control system for the supervision of a wastewater treatment pilot plant are presented. The operation scheme is based on an A2/O system (anaerobic, anoxic, oxic) and includes organic matter removal, nitrification/denitrification, and Enhanced Biological Phosphorous Removal (EBPR). The hardware architecture involves different supervision levels, including two autonomous process computers (plant control and analysers control) and a PLC. The software architecture includes a Knowledge-Based Expert System (KBES) as the top control system. The KBES has been developed in G2, an expert system development environment based on object-oriented structural design. This system is fed with data obtained from the plant monitoring (in-line, on-line and off-line data) and with actuation data of the lower control levels. Using this information, the KBES supervises the pilot plant in order to help with fault detection and plant maintenance, but also modifies setpoints and other variables of the local control level to adapt the system to the different influent conditions. The overall system has been implemented and validated at pilot scale.