Description Of Control System Research Articles

Modeling of hybrid control systems using the DEVSLib Modelica library

DEVSLib is a free Modelica library, developed by the authors, that supports the Parallel DEVS formalism. The library is mainly designed to model discrete-event systems. It also includes interfaces to communicate the DEVSLib models with the rest of the Modelica libraries. Thus, the library can be used in the development of multi-domain and multi-formalism hybrid models using the object-oriented methodology supported by Modelica. This manuscript presents the hybrid system modeling capabilities included in DEVSLib. In particular, these functionalities are applied to the description of hybrid control systems. A case study of a supermarket refrigeration system, using the traditional control approach, is discussed. Three implementations of the plant and its controllers have been developed and are described. The system is simulated reproducing the day and night conditions, and the results from the three implementations are compared. DEVSLib is freely available for download at http://www.euclides.dia.uned.es.

IPM Machine Drive Design and Tests for an Integrated Starter–Alternator Application

This paper deals with an integrated starter-alternator (ISA) drive which exhibits a high torque for the engine start, a wide constant-power speed range for the engine speedup, and a high-speed generator mode operation for electric energy generation. Peculiarities of this ISA drive are thus its flux-weakening capability and the possibility to large torque overload at low speed. The focus on the design, analysis, and test of an interior permanent-magnet motor and drive for a prototype of ISA is given in this paper. In details, this paper reports on the design of stator and rotor geometries, the results of finite-element computations, the description of control system, and the experimental results of prototype tests.

PASSIVE RESPONSE CONTROL SYSTEMS FOR SEISMIC RESPONSE REDUCTION: A STATE-OF-THE-ART REVIEW

Research and development of seismic response control devices has gained prime importance recently, due to an increased number of devastating earthquakes. Passive control systems are now accepted all over the world and hence research in this area is continuing to develop reliable, efficient and cost effective devices along with constitutive modeling. This paper begins with qualitative description and comparison of passive, active and semiactive control systems. Further, it mentions advantages of passive control systems over the others. A detailed literature review of passive devices is then provided which includes the historical development of the devices, their dynamic behavior, testing of these devices incorporated in the structural models and their analytical formulations. The pros and cons of these devices in retrofitting of structures and their first and recent applications in a wide variety of structures are also discussed. The passive response control systems that are discussed include viscoelastic dampers, yielding dampers, viscous dampers, friction dampers, tuned mass dampers, tuned liquid dampers, tuned liquid column dampers, superelastic dampers, like shape memory alloy dampers and base isolators.

AFECS. multi-agent framework for experiment control systems

AFECS is a pure Java based software framework for designing and implementing distributed control systems. AFECS creates a control system environment as a collection of software agents behaving as finite state machines. These agents can represent real entities, such as hardware devices, software tasks, or control subsystems. A special control oriented ontology language (COOL), based on RDFS (Resource Definition Framework Schema) is provided for control system description as well as for agent communication. AFECS agents can be distributed over a variety of platforms. Agents communicate with their associated physical components using range of communication protocols, including tcl-DP, cMsg (publish-subscribe communication system developed at Jefferson Lab), SNMP (simple network management protocol), EPICS channel access protocol and JDBC.

Vehicle Longitudinal Motion Simulation by Analytical Automatic Machines

In work examines an aspect of the human-machine system "Automobile-Environment-Driver" model construction, associated with a description of the vehicle longitudinal motion control systems of, allowing to reproduce controlled automobile motion under normalized conditions with various functionals of qualities.

Time variant Hamiltonian control systems – a covariant approach

AbstractIn this contribution we present an intrinsic description of time variant Hamiltonian control systems. This formulation is based on the splitting of the state bundle and the use of appropriate covariant derivatives, which guarantees that the structure of the equations is invariant with respect to time variant coordinate transformations. (© 2008 WILEY‐VCH Verlag GmbH & Co. KGaA, Weinheim)

Analysis and design of polynomial control systems using dissipation inequalities and sum of squares

Polynomial control systems are control systems where the control system description is given in terms of polynomial nonlinearities. One encounters this class of control systems in a wide range of applications. In particular, in process control and systems biology, many control problems can be modeled as, transformed into, or approximated by polynomial control systems. The purpose of this paper is to give an introduction to and an overview over analysis and design of polynomial control systems using dissipation inequalities. Recent results for rather classical analysis problems, like in stability analysis, are presented as well as new results in emerging design problems, like synchronization. In particular, the analysis of the minimum phase behavior, the stability analysis of differential-algebraic systems with higher index, and the design of synchronizing feedbacks is carried out using dissipation inequalities. To ensure practical applicability, semidefinite programming and the sum of squares decomposition is used, to solve the obtained analysis and design dissipation inequalities in a numerically reliable and efficient way.

On the extension of the Korobov's class of linearizable triangular systems by nonlinear control systems of the class [formula omitted

We give the complete description of nonlinear control systems of the class C 1 with one-dimensional control which are feedback linearizable by means of a change of the control of the class C 1 and a change of variables of the class C 2 as well as the control systems which are linearizable by means of a change of variables only. The both results are originated from the approach proposed by V.I. Korobov in 1973 for the linearization of triangular control systems.

Trial of dynamic signature verification for a real-world identification solution

This paper describes a recent trial of a biometric identity verification system. The prototype system developed provided a means of automatically issuing pass cards providing access to a major site. The paper begins with the description of a practical problem — access control to a major industrial site, and the potential benefits a biometric technique might offer. This is followed with a description of a prototype access control system, and a review of dynamic signature verification as a biometric technique. Results from the trial are presented, followed by an analysis of the results. The paper concludes by summarising the findings and describing possible ways forward.

Control System of the Microsatellite “Micron”

Description of magnetic control system of the microsatellite “Micron” is represented. Microsatellite developed in State Design Office “Yuzhnoye” in accordance with plans of experimental-design works of National Space Agency of Ukraine. Control system developed in scientific manufacturing company “Hartron-CONSAT” Main attention in the paper is devoted to problems of high-performance algorithms designing on estimation parameters of the satellite by means of magneto meter measurements. The series of new results, obtained during the designing of control system, allowed to solve successfully the problems for estimation of satellite motion parameters by magnetometer information is represented. The efficiency of suggested algorithms is confmned by simulation results.

External model and SyncCharts description of an automobile cruise control system

In this paper, a generic model is developed for smart instruments, and SyncCharts of the synchronous model are used to specify automated systems. The generic model provides an external description, which is the user's point of view, and the SyncCharts model gives a behavioral model of the system. From the complementary information offered by these two models of a device, a method to obtain a coherent SyncCharts from a part of the external model is proposed. The classical example of an automobile speed cruise control system is used for illustration.

Semi-active control systems for seismic protection of structures: a state-of-the-art review

As passive structural control systems begin to see an increased acceptance within the earthquake engineering community, strong research efforts have been shifted towards the development of semi-active structural control systems. To place semi-active control systems within a proper frame of reference, this paper begins with a qualitative description and comparison of passive, active, and semi-active control systems for protecting structures subjected to earthquake induced ground motion. A detailed literature review of semi-active control systems is then provided which provides references to both theoretical and experimental research but concentrates on describing the results of experimental work. Specifically, the review focuses on descriptions of the dynamic behavior and distinguishing features of various systems which have been experimentally tested both at the component level and within small-scale structural models. The semi-active systems which are reviewed include stiffness control devices, electrorheological dampers, magnetorheological dampers, friction control devices, fluid viscous dampers, tuned mass dampers and tuned liquid dampers. The review clearly demonstrates that semi-active control devices have the potential for improving the seismic behavior of full-scale civil structures.

Mathematical Strategies Common to Mechanics and Control

This paper deals with strategies common to mechanics and control. Design methods, well known from simple mechanical control systems, are extended to the broader class of affine input systems. Since here exterior differential systems are used for the description of control systems, methods of exterior calculus, like the derived flag, can be applied to the problems of accessibility, observability, and exact linearization. The H∞-design of nonlinear control can be considered as an application of the theory of differential games. By refining this design for Hamiltonian control systems we present an exact solution of the Hamilton-Jacobi-Isaacs-equation for a special problem of optimal damping. On the basis of an infinite dimensional Hamiltonian system, in this case a beam with piezoelectric layers, the applicability of the presented methods, as well as the realizability of the feedback law, is shown.

Sliding mode thermal control system for space station furnace facility

This paper addresses the decoupled control of the nonlinear, multi-input-multi-output, highly coupled space station furnace facility (SSFF) thermal control system. Sliding mode control theory, a subset of variable-structure control theory, is employed to increase the performance, robustness, and reliability of the SSFF's currently designed control system. This paper presents the nonlinear thermal control system description and develops the sliding mode controllers that cause the interconnected subsystems to operate in their local sliding modes, resulting in control system invariance to plant uncertainties and external and interaction disturbances. The desired decoupled flow-rate tracking is achieved by optimization of the local linear sliding mode equations. The controllers are implemented digitally and extensive simulation results are presented to show the flow-rate tracking robustness and invariance to plant uncertainties, nonlinearities, external disturbances, and variations of the system pressure supplied to the controlled subsystems.

A hierarchical platform for implementing hybrid systems in process control

This paper describes a development platform for the description, analysis and implementation of real-time control systems, consisting of a mixture of continuous and discrete components. Hybrid and discrete-event system techniques are used for formally defining the control and supervisory system requirements. These requirements result from functional characteristics specified for the process to be controlled. Based on the specifications, a series of control components belonging to a finite set of object classes is defined and arranged in a hierarchical architecture. The hierarchical topology is a simple tree, where any component has a single parent. Object-oriented technologies are used to implement the notion of component classes. With this formal description of process functionality, a computer software generator interprets the control specifications and produces executable control software. This software reacts to environmental responses by executing the supervisory and control actions required to achieve the desired process behavior. The paper only describes the conceptual idea of the proposed control development platform in a general manner. As an example, an application of this platform is presented for developing the control software for a production process that converts metallic sodium from nuclear reactors to sodium carbonate for safe waste disposal.

Generalized matrix Euclidean algorithms for solving diophantine equations and associated problems

Based on the matrix fraction descriptions of multi-variable control systems, this paper presents the generalized matrix Euclidean algorithms for solving Diophantine equations and associated problems. A chain rule is developed for finding the greatest common right(left) divisor of two square(non-square) polynomial matrices and the irreducible right(left) matrix fraction description from the reducible or irreducible left(right) matrix fraction description. Also, the development of multi-variable pole-assignment controllers are discussed for engineering applications.

Industrial Control Systems for CIM

Abstract The integration of information and control functions in the sub-systems of a production system requires some kind of central coordination, an Industrial Control System, ICS. The choice of ICS for a given process, however, is a delicate one. The ICS should provide the required functionality and performance at a minimum cost, while providing sufficient long-term flexibility to assure a low life cycle cost. Today, it is not uncommon that a user chooses a too expensive or, even worse, too “restricted” ICS. In this study, a number of commercially available ICS's, normally used within different fields of application, have been investigated. Several similarities between the studied ICS's have been found. They all hold an internal process image, consisting of static and dynamic information. Continuous updating of the dynamic information requires acquisition and time-tagging of real-time data. Contents of the process image are visualized to an operator via a presentation interface. Supervisory functions, such as alarm handling, and off-line functions, e.g. storage handling, also operate on the image of the process. The functions for control of the production system, e.g. down-line loading of programs to machines, normally operate directly on the process. Data engineering tools are utilized to define, modify, and extend the functionality of the ICS. The study has shown that of the examined ICS's, the area of use does overlap. Hence, a user could choose an ICS that originally was developed for another field of applications. To make it possible for a user to find an optimal ICS for his process, however, an objective way to define the requirements is needed. The study indicates that focus should be placed, in a higher degree than today, on the fundamental requirements upon functionality and performance originating from the process, organization, human resources, and methods of work. A model for description of Industrial Control Systems, supported by a consistent terminology, is needed. Some concepts on these subjects are presented in the paper.

Myoelectric Prostheses for the Limb-Deficient Child

Since their initial introduction in 1971, myoelectric prostheses have gradually become the option of choice for many children and families. Marked improvements in technology and prosthetic management now make it feasible to fit children as young as infancy. This article begins with a discussion of the controversy within the professional community over age appropriateness and cost effectiveness of myoelectric fittings for children. The article then presents an overview of current clinical practice, including principles of management and a description of control systems, sockets, and components considered suitable for use with children.

Accelerator control

The concepts of light-energy accelerator control are described. Some hard- and software requirements are discussed. The variety of possible solutions is illustrated by a short description of control systems in some selected high-energy laboratories.

A structured approach to analysis and design of complex systems

An automatic control system for managing the heating of a modern building may involve several thousands of components and feedback loops. As such systems grow, decomposition into (nested) subsystems becomes increasingly necessary. The subject of the poster session is complexity in large scale systems. We think we can make the computer manage the complexity in any system that can be described in a block-diagram. A variety of complex systems are represented by different types of block-diagrams. They have one theoretical concept in common: connectedness. Directed graphs (digraphs) can describe the fundamental concepts of structure and reachability, and graph theory provides a consistent mathematical theory of it. The South Bank Polytechnic and the Technical University of Denmark are actively concerned through industrial collaborators with problems of energy management for modern buildings control of waste water in urban sewage networks fuzzy control of industrial processes engineering management systems expert system design for fault diagnosis and food poisoning diagnosis. All these problems require a tool for i) inputting and editing of graphs, and ii) an executable, array based model. In the late 70'ies Franksen, Falster & Evans (1979) proposed a description of control systems based on a Boolean array representation of digraphs. At APL87 Fordyce & Sullivan presented an inference mechanism for VLSI chip manufacturing, also based on Boolean array structures (Fordyce & Sullivan, 1987). The APL89 conference had a similar nested array approach (Jantzen, 1989), and recently, the beginning of a whole theory, based on the 'digraph approach' has been published (Reinschke, 1988). The poster session will present a digraph model, in which the nodes contain tree-structured, nested data. The oriented arcs display the flow of information. Internally each level of the diagram will be stored in a nested array. The user can draw the diagram directly on screen using a digitizer. The session will include live demonstrations of fault diagnosis on a water tank model of a sewage network a structured approach to expert system design interactive graphics for object oriented visual programming (APL2) frame based data systems (APL2). The demonstrations will emphasize the PC, PS/2 and RT/PC based aids to complexity management. The digraph approach promises speed and space gains due to the purely Boolean array representations, as well as user-friendliness due to automatic decomposition techniques.