Characteristics Of Automatic Control System Research Articles

Algorithmic Support of Adaptive Automatic Control Systems with Data Compression

Introduction. The exponential growth of measurement information caused by ongoing complication of technical and production facilities necessitates the development of improved or brand new information and measurement systems, including those performing adaptive automatic control functions. Automatic criteria-based selection and reduction of measurement information continuously supplied by multi-parameter sources characterizing the objects under study require algorithms ensuring reconfiguration of automatic control systems during operation. In comparison with automatic control systems based on time-division channelling, the considered adaptive systems provide timely information on the pre-emergency and emergency operation of a facility.Aim. To develop an algorithmic support for adaptive automatic control systems using asynchronous-cyclic and parallel-sequential operating algorithms, as well as to compare the proposed algorithms in terms of their, control reliability, compression ratio, operation speed and the error associated with multi-channelling.Materials and methods. The algorithms proposed for supporting the operation of adaptive systems were developed on the basis of queuing theory and simulation modelling using the MatLab/Simulink programming languages, C++.Results. The developed algorithmic support for automatic control systems based on asynchronous-cyclic analysis of deviations allows the amount of redundant information to be reduced by more than 4 times and the operation speed to be increased by 1.5 times. The developed algorithmic support for automatic control systems based on parallel-sequential analysis of deviations allows the error associated with multi-channelling to be reduced by 1.4 times, thereby bringing the control reliability of such systems closer to that of continuous-control systems. An analysis of the graphs of the error associated with multi-channelling showed that the automatic control systems based on parallel-sequential operational algorithms are invariant to the law of distribution of input quantities, compared to the systems based on asynchronous-cyclic operational algorithms.Conclusions. The proposed algorithmic support can significantly decrease the redundancy of information and improve the metrological characteristics of automatic control systems. The use of the developed algorithms in automatic control systems based on time-division channelling render their control reliability comparable with that of continuous-control systems.

A Digital Control System for the Power Conditioning Unit of Spacecraft

The paper considers the design concept and estimated characteristics of automatic control systems for the power conditioning unit of spacecraft with a digital control system. The purpose of the present work is to develop a structure of an automatic control system providing the following: power improvement for the power conditioning unit due to the parallel connection of power conditioning modules; high structural reliability of the power conditioning unit designed for two or more failures due to the channel redundancy for the digital control module and a special design for the majority logic element; the organization of the required operating sequence of power sources and their efficient use; high speed and accuracy of regulation of voltage output approaching the analog control systems. The expected results of channel redundancy for the digital control module have been confirmed using the experimental prototype. The authors' results include the generation of the superordinate control level without raising requirements to the reliability indices of the majority logic element; this control level has been generated using the hierarchical digital control system with a redundant control system.

ЭНЕРГЕТИЧЕСКИЕ СИСТЕМЫ СУДОВЫХ ДИЗЕЛЬНЫХ ЭНЕРГЕТИЧЕСКИХ УСТАНОВОК: ОБОСНОВАНИЕ ТРЕБОВАНИЙ К НАДЕЖНОСТИ

The article touches upon reliability issues of energy management systems (EMS) of marine power plants in emergency situations caused by disturbance of the working media consumption and their subsequent recovery. The mathematical model of processes allows to determine the nature of changes in temperature and pressure of water and lube oil in EMS systems. The requirements to the characteristics of automatic control systems of the marine power plant have been formulated. Basic provisions of the reliability theory are followed by presentation of methods of calculating reliability indices of complex technical systems. The article presents the results of the study of non-stationary modes and reliability indices. Reasonable requirements for automated control systems were obtained through the analysis of working environments and of equipment operating in non-stationary modes, non-exceedance of safety limits of marine power plant operation being taken as the admissibility criterion. Besides, there are possible special modes resulted from emergency situations caused by the power plant equipment failure. Hence, for operation and design of the analyses it is important to study changes of working media in the circulation systems, which resulted from the failure of the pumps. Basic circuit of lubrication and cooling systems of the ship diesel power plants has been approved as recommended by the company "MAN B&W" for slow speed diesel engines standard series MC. Among the recommended schemes there was approved the scheme of the main engine with an autonomous cooling circuit. Schematic diagram of energy systems of a diesel power plant has been made under recommendations of the engine developer. Specifications of the component parts of the ship diesel power plant have been taken as standard for manufactured machinery. A low running L90MC-C four-cylinder main engine manufactured by "MAN B&W" was chosen as a research sample. A mathematical model, as applied to the given problem, consists of 10 algebraic equations for nonsteady working media consumption and 18 differential equations for nonsteady heat transfer in heat exchangers, as well as equations for transport delay in the lubrication systems of internal combustion engines.

Adaptive pseudolinear compensators of dynamic characteristics of automatic control systems

Adaptive pseudolinear gain and phase compensators of dynamic characteristics of automatic control systems are suggested. The automatic control system performance with adaptive compensators has been explored. The efficiency of pseudolinear adaptive compensators in the automatic control systems with time-varying parameters has been demonstrated.

Using of modified symmetry principle of the structural schemes for automatic control systems synthesis

The solution of inverse dynamic problems using the symmetry principle of structural schemes can be a basis for the synthesis of automatic control systems of technical objects. This approach requires compensation of the dynamic properties of the control object. Most scientific papers idealize the object, that is assume that its dynamic characteristics can be fully compensated by controllers. The impact of transfer functions of modifying links on dynamic and static characteristics of automatic control systems is also understudied. The possibility of using methods for solving inverse dynamic problems for the synthesis of automatic control systems of technical objects is investigated. The mathematical modeling confirmed that ideal tracking of inputs under the full compensation of dynamic properties of the control object is impossible in real systems. The rules, which allow determining the inverse model of the control object directly by its structural scheme in the first canonical controllability form, without having to convert differential equations, are formulated. The modified symmetry principle of the structural schemes, which lies in introducing the integrating link to a direct branch of the closed system, which is included consistently with the inverse model, and provides formation of achievable dynamic characteristics desired with a limited gain is developed.

АЛГОРИТМ іДЕНТИФіКАЦії ОБ’єКТіВ КЕРУВАННЯ

The article represents the parameters identification algorithm of the second order element, which approximates the experimental curve of the transitional process, using a nonlinear least-squares method. The main purpose of the work is to compare the methods of selection of initial data for identification algorithm: by uniform distribution of dots on the ramp and according to the characteristic dots, and detection of approximation errors depending on the number of dots on the ramp. Obtained research results indicate that at approximation of equivalent control object by differential equation of the second order, it is appropriate to take characteristic dots of the curve of transitional transformer of equivalent control object, as the initial data, because to provide a given accuracy, they are required 1.5-3 times less than the algorithm of equal distribution of dots. It further allows facilitating the analysis and optimization of dynamic characteristics of automatic control system and simplifying the search of settings of regulator according to quadratic optimization function.

Significance evaluation technique for error conditions in data processing within enterprise automatic control system

A problem of increasing the efficiency of automatic control system (ACS) in the field of reliable data processing is considered. An emphasis is placed on integration of information resources protection system (IRPS) with ACS of the enterprise (ACSE), as well as on relationship between validity of the processed data and qualitative descriptions and characteristics of ACS. A certain technique of transition from qualitative characteristics to quantitative values is suggested, with application to error conditions evaluation in data processing within ACS.

Enhancing Dynamic Accuracy and Quality Indices of Transient Processes of Magnetic Suspension Automatic Control System by Means of Differential Connection.Part I.Analysis of Dynamic Characteristics of Automatic Control System of Carrier Magnetic Suspension

Enhancing Dynamic Accuracy and Quality Indices of Transient Processes of Magnetic Suspension Automatic Control System by Means of Differential Connection.Part I.Analysis of Dynamic Characteristics of Automatic Control System of Carrier Magnetic Suspension

Some Fundamental Considerations in the Application of Automatic Control to Continuous Processes

Abstract Certain fundamental characteristics of continuous processes and automatic controllers are presented in this paper in order to establish a framework for a suggested terminology. A specific object is to assist in the work on standard terms being conducted by the A.S.M.E. Committee on Industrial Instruments and Regulators. The authors’ treatment is essentially nonmathematical. Illustrations used deal primarily with the control of temperature. Attention is focused on the effects of important process lags through the analysis of elementary heating systems in which they are individually predominant. Characteristics of automatic control systems are discussed without going into the constructional details of particular mechanisms. Curves showing the response to sudden load changes serve to illustrate different types of corrective action. The final section of the paper is devoted to a critical discussion of suggested terms.