Parameters Of Control Object Research Articles

Self-tuning PID feedback control method for magnetic suspension active vibration isolation system with parameters uncertainty

A self-tuning PID (Proportion-Integral-Derivative) control method based on the adaptive mechanism was proposed for the magnetic suspension active vibration isolation system with the characteristics of nonlinear, time-varying, and model parameter uncertainty. The controller identified the controlled object parameters online and solved the controller parameters in real time. To test the effectiveness of the proposed method, a six degree-of-freedom (DOF) magnetic suspension active vibration isolation system was designed and built. The six DOF dynamic model of the vibration isolation system with uncertain model parameters was derived for control. Experiments were carried out and compared with the control effects of the tradition PID control and cascade PID control algorithm. The experimental results show that the proposed self-tuning PID controller has more outstanding practicality and effectiveness in solving the model parameter uncertainty problem compared with the existing studies at home and abroad, and it also proves that the control method has a good isolation effect on the wide band disturbances.

Повышение точности идентификации и настройки линейных систем с регуляторами состояния при помощи искусственной нейронной сети

High potential capabilities of control systems with state controllers can be realized only if automatic tuning tools are available. Since the tuning is carried out in real-time mode, which places increased demands on performance, it is proposed to use an artificial neural network to reduce its duration. However, under the conditions of noise in the measurement channels, the quality of identification of the parameters of the control object is significantly reduced. In this regard, the aim of the study is to find the optimal composition of measurement channels at the network input, which allows minimizing the influence of noise on the estimates of object parameters to improve the quality of tuning. During the study, state space methods are used to design a vector-matrix model of an object and synthesize a state controller. A radial artificial neural network is used to solve the problem of identifying the parameters of a vector-matrix model. The training of networks, the study of the effectiveness of their work, as well as the development of models is carried out using the tools of the MatLab software package. The authors have developed the method to select the optimal composition of measurement channels which gives the maximum signal-to-noise ratio and forming the corresponding structure of a radial artificial neural network to solve the problems of object parameters identification and control system tuning with state controller. It is proposed to use the sensitivity functions of the state coordinates of control object parameters variation to estimate power of information signals at the inputs of neural network. The results of the conducted computational experiments have confirmed the effectiveness of the developed method, which makes it possible to increase the accuracy of identification and tuning of systems with state regulators under noise conditions. The obtained results can be used to ensure a given quality of control with parametric uncertainty of the object.

Construction of Ideological and Political Practice Teaching System of Documentary Creation Course Based on Deep Learning

In order to improve the effect of landscape design, a landscape design method based on distributed integrated model is proposed. Based on the spatial location information, ancient books and documents, POI data, and text data of garden landscape, a multisource distributed data distribution model of garden landscape design is established. Extract the word frequency of keywords to calculate the garden heat, and analyze the pattern and changes of garden landscape according to the landscape index. The distribution and integration model of landscape design is established, which takes history and culture, landscape ecology, tourism, and health as the control object parameters, and the spatial relationship between landscape and its adjacent areas is studied by image integration. The virtual three-dimensional visual reconstruction method is used to optimize the landscape design and image processing. The simulation test results show that the distributed integration ability of landscape design using this method is better, and the visual performance effect is better, which improves the visual expression effect and design quality level of landscape design.

Self-tuning ship autopilot based on the neural network concept: An empirical approach

ABSTRACT Ship autopilots are one of the key factors that guarantee the safety and economical efficiency of marine transportation. In this paper, a self tuning ship autopilot based on neural network concept is introduced. A multilayered feed forward neural network with a fixed part and a tunable part is used for tuning the feedback coefficients of a conventional controller. The connections of tunable part are updated without gradient calculation and iteration. No prior information about controlled object parameters is required. The proposed controller is applied to mathematical models of real ships. The designed autopilot performance is validated for operation cases in calm water and sea wave. The comparison to PID controller and some other control techniques is conducted. The results show that proposed concept may be used for designing ship autopilots and successfully applied for course control of real ships.

Synthesizing robust control systems for mechatronic objects with digital state controllers and observers

Currently, digital controllers with state observers are widely applied in automatic control systems for mechatronic objects, which great potential abilities are caused by structural flexibility and developed methods of synthesis. However, during design and practical implementation of the systems there is problem of robustness, associated with parametrical uncertainty of typical mechatronic objects. Most methods for synthesis of robust control systems are based on application of continuous mathematical models and do not take into account specific of digital realization of controllers with state observers. Methods of state space, modal control, digital system design, numerical optimization algorithms and simulation in MatLab environment were used. We propose a method of synthesizing robust digital modal control systems with state observers based on generating dynamic system characteristics within the areas of parametric robustness. Further, low sensitivity of the system to changes in controlled object parameters is ensured by the minimal phase character of the complex controller transfer function, while low sensitivity to changing parameters of the controller itself is ensured by excluding positive feedback in both control and adjustment circuits. Developed recommendations of choosing dynamic characteristics of state controller with observer loops within robustness areas and of forming rational state observer structure allow us to synthesize digital automatic control system with low sensitivity for variation of both control object parameters and inherent controller parameters.

Synthesis of a robust control system for two-mass electric drive by H∞-theory

The practice of designing and operating control systems for industrial facilities has shown that systems synthesized according to the criteria of modular and symmetric optima, as well as by quadratic quality criteria, are sensitive to changes in the parameters of the controlled object, incoming characteristics, disturbing influences, the structure and parameters of the object model changing, which used in control loops. Such systems can lose optimality as well as productivity, if information about the object and operating environment is known with some probability or uncertainty. For an industrial electric drive, changes in load torque, moment of inertia of rotating parts, supply voltage and environmental characteristics (temperature, vibration) are especially significant. These changes affect both the mechanical characteristics rigidity and the transients’ quality.
 Robust control systems provide a required quality of work when changing the characteristics of impacts and instability of the control object parameters in a wide range. In the presence of uncertainties, a robust controller provides robust stability and quality for all admissible uncertainties.
 The synthesis of robust control systems with an H∞-speed controller of a two-mass electric drive by methods of H∞-theory is presented in order to prove the possibility of using algorithms for a given stabilization and speed control, as well as providing the necessary degree of sensitivity to parametric and coordinate disturbances acting on the control object. Application of the method of robust controllers’ synthesis taking into account the requirements for the quality of a controlled coordinate transient processes in the control system. The analysis of the operation of a synthesized robust system with an H∞-speed controller using digital modeling on mathematical models in the MATLAB / Simulink environment is carried out. The possibility of the speed independent control, the steady-state error and the nature of the transient processes of the controlled coordinate in the synthesized electric drive control system is shown.

Determination of the Area of Robust Stability of the System on the Basis of V. L. Kharitonov’s Theorem

The parameters of the object of regulation during operation due to various reasons may vary. These changes can lead to a change in the performance indicators of the automatic system, as well as its stability. This article proposes an approach to determine the range of acceptable values of the parameters of the control object of an automatic system with a PID controller, in which the system will remain stable. Thus, the problem arises of analyzing an automatic control system given not only by a single model with clearly defined parameters, but by a family of models belonging to a given set — the task of robust regulation. The search for ranges in which the parameters of the regulated object can change is based on the solution of the nonlinear programming problem in this paper. The conclusion of the objective function and constraint system using the theorem of V. L. Kharitonova on the robust stability of linear systems. The main idea is that each parameter of the regulatory object can be changed by some value hi1 in the direction of decrease and by hi2 — in the direction of increase. Replacing the notation used in the theorem of V. L. Kharitonov, the lower and upper boundaries of the change of parameters by the sum and difference of the nominal values of the parameters and the corresponding hi1, hi2, we get a system of restrictions. Moreover, for the stability of Kharitonov polynomials, it is most convenient to use the Lienar-Shipar criterion. The larger the values of hi1, hi2, the wider the ranges of variation of the parameters, and the smaller the inverse of the sum of these values. Based on this statement, the objective function is formed. It should be noted that the condition for the considered automatic system on which the proposed approach is based is sufficient, but not necessary, since the coefficients of the polynomial are interdependent. An example with the help of which the proposed approach is demonstrated is considered. This approach can also be applied to other linear systems for which theconditions of V. L. Kharitonova.

Interval-parametric synthesis of a robust controller on a base of characteristic polynomial with desired stability in a sector

In the paper a characteristic polynomial of a linear control system which coefficients include interval parameters of a control object and adjustable parameters of a controller is considered. In order to find polytope of controller parameters providing desired sector stability of a polynomial, values of polynomial coefficients limits are found on a base of desired oscillability degree of a system. On a base of these calculations a controller synthesis method is developed. Application example of the method proposed is also provided.

Controller settings search area determination in the condition of reduced sensitivity to control object parameters drift

A definition method for the area of controller admissible parameters set-up in an aircraft, machine-building and other industries is offered in this article. Admissible adjustments areas of controller parameters are defined, at which closed control systems have smaller sensitivity to possible deviations of object parameters regulation during their operation. The examples of method applied to automatic control systems of vacuum in the furnace and drum-type boiler flow rate controller are considered.

SYNTHESIS AND ANALYSIS OF ARC FURNACE ELECTRICAL MODE CONTROL SYSTEM ON THE BASIS OF THREE-DIMENSIONAL PHASE CURRENTS VECTOR DISTRIBUTION

Goal. The purpose of the article is to create the method for the operative synthesis of an arc steel-melting furnace (ASF) electric mode (EM) control signal on the basis of a three-dimensional arc currents vector, which takes into account the stochastic nature of the processes in the melting space and power circuit and has low sensitivity to the control object parameters changes, as well as development of the control system structure for its implementation. Method. The basis of the created control method is formed on the statistical theory of dynamical systems, as well as the provisions of the statistical theory of optimal control based on the Fokker-Planck-Kolmogorov equation, which enables to synthesize operational control by the criterion of approaching the regulated coordinate distribution density to the d-function, that is to minimize the dispersion of the three-dimensional furnace phases arc currents vector. Results. The system of equations for operational real-time calculation of control influences of the thyristor switch of phase inductors, included in the power supply circuits of three-phase arcs, and the structural scheme of the adaptive contour for the formation of three-dimensional phase currents vector dispersion for the implementation of adaptive optimal control were obtained. Scientific novelty. For the first time, based on the Fokker-Planck-Kolmogorov equation, we obtain a system of equations representing a mathematical model of a stochastic adaptive optimal control of the arc furnace electric mode by the criterion of a minimum dispersion of three-dimensional phase (arcs) currents vector, which enables, in comparison with known methods, to increase dynamic precision of the arc currents stabilization at the level set by the criteria of energy efficiency and electromagnetic compatibility values. Practical value. The use of the proposed adaptive optimal control model and structural system scheme for its implementation allows, in comparison with the serial arc power regulators, to improve the dynamic accuracy of the arc current currents stabilization at the level of given optimal settings and, based on this, to improve the energy efficiency and electromagnetic compatibility indices of the arc furnace and power supply network.

Research on Permanent Magnet Synchronous Motor Drive System of Electric Vehicle Based on Fuzzy Control

The performance of permanent magnet synchronous motor is an important indicator to measure the performance of motor. Since the conventional PID control is only applicable to the linear control system, the conventional PID control cannot satisfy the control performance requirements for a nonlinear control system such as a permanent magnet synchronous motor or a time-varying system. Fuzzy control does not depend on the precise mathematical model of the controlled object, and it has strong robustness and anti-interference ability to the changes of the controlled object parameters. In this paper, the traditional PID control and fuzzy control are combined, and the PID parameters are adjusted online by the fuzzy controller, so that the permanent magnet synchronous motor speed regulation system has good dynamic and static characteristics. In this paper, MATLAB is used to model and simulate the permanent magnet synchronous motor vector control system based on fuzzy control. The results show that the fuzzy controller has excellent performance in suppressing the overshoot and anti-disturbance.

FUZZY SUPERVISOR FOR PID CONTROLLER

Introduction: PID regulators are an important industrial automation tool. However, the traditional ways of their customization involve experiments with the plant, reducing the control system efficiency when the operating conditions change. To solve this problem, you have to use an adaptation loop which automatically changes the regulator parameters when the quality indicators deteriorate. Purpose: Developing a structure and an algorithm for a fuzzy supervisor of a PID controller in order to improve the operation quality in the context of uncontrolled changes in the plant parameters. Results: We propose two options for organizing a fuzzy supervisor. The first option involves continuous changing of the controller parameters based on the information about the current control error. The supervisor is trained offline with the help of a genetic algorithm. This approach makes the application universal, but the resulting structure is a black box. The second option is using transient process quality estimates; it can be used when the input signal periodically changes. The controller parameters are changed using fuzzy rules with clear semantics. It is shown that systems with a fuzzy supervisor can reduce the overshoot or static error which both can occur when the control object parameters change. The system operation was simulated using MatLab Simulink. Practical relevance: The use of PID controllers with fuzzy supervisors can be useful in the design of control systems for a wide range of dynamic plants.

Development of knowledge­based control systems with built­in functions of rules verification and correction

Two improved models of control rules were proposed. A model in a form of AND/OR graph; in contrast to the known graphical model of general rules, is based on dividing the rules into groups based on the controlled object state. The graph contains special markup that allows to convert the graph paths corresponding to the rules into Boolean expressions including formulas for both and inverse rule sets. The basic formulas of the rules model in a form of Boolean expressions cannot be constructed for general rules and based on these formulas the three methods for verification of the rules were developed: ‒ the method for verifying the control rules premises for inconsistency based on the SAT problem for Boolean formulas; ‒ the method for verifying the control rules for completeness based on visualization of both direct and inverse rules with conclusions in “inverse” rules opposite to the conclusions of the original rules; ‒ the method for verifying reachability of the object state vertices from the control rules. The main advantage of these methods is that they allow to find errors in the rules at early stages when specialists in the field for which the knowledge-based system is used (experts and decision makers work with them). The specificity of the control tasks makes it possible to do this effectively from the point of view of analysis and verification of the rule quality. The developed procedure of the control rules verification and correction assists in to bringing together and placing in a correct order various types of verification and correct errors in an automated mode. Main components were proposed for knowledge-based control systems: the rule editor for knowledge engineers and experts and the control system itself which includes extraction of the controlled object parameters essential for analysis as well as analysis of these parameters and their transfer to a DM for making a decision. A rule editor has been developed and control systems for two domains: safe operation with electric installations and control of computer networks. The presented experimental results on the management of the training process using the developed systems have shown that the number of errors in the created rules was reduced. When verifying for reachability of the object states, errors in an average of 5.4 % control rules were found and removed. When verifying for inconsistency of the rule premises, errors were found and corrected on average in 11.5 % of rules. When verifying for completeness, the rules base was expanded by on average of 12.3 %. In addition, due to consulting, verification and correction of the rules, the time spent by trainees on execution of their work was reduced by an average of 8 %.

RESEARCH FRAMEWORK FOR SYSTEM SECURITY OF TECHNOLOGICAL & INNOVATION SYSTEMS

The purpose of this study is to consider the main aspects of system security theoretical concept and practical aspect within the technological & innovation systems research methodology development according to their considering as structurally complicated systems. Methodology. In this study, we propose to use the concept of technological & innovation systems, in which it is analysed the development of the technological field in terms of structures and processes that support or impede its development. So this approach can be considered as an expanding to techno-socio-economic analysis, considered for the innovation system in our previous studies. Results. The problem of study comes from the national security and defence objectives, which can be achieved within the national innovation systems, considering new meaning and problems in the age of globalization and high technologies development. We can underline that the important factor of technological & innovation systems system security consists in system identification within the management theory as the determination of the structure of the system and its parameters by analysing input data and system outputs. At the same time, we can note the system specifics, e.g. the identification of industrial systems security deals with the establishment of the identity of production facilities an ecological security etc. The most important relationships of innovation & technological systems designing that allow establishing appropriate adaptive management decisions were proposed. For the development of combined models of innovation & technological systems security, the main aspects of this type of systems were considered. Practical implications. Based on this, the author proposed to use system indicators for security providing process. Using these indicators, we can identify system synchronous development speed and autonomous of speeds of security providing process. The technological & innovation systems security management is proposed to be analysed in two interrelated subsystems: self-organizing subsystems and technological subsystem. The main activities for the system security of highly complicated system providing were proposed. Value/originality. Based on the foregoing, the authors proposed to use security relationships adaptive management as a set of methods that can generate management systems, able to change the security-related parameters of regulator or controller structure according to the change of control object parameters or external disturbances acting on the control object.

Обеспечение надежности технологических процессов вибрационной отделочно-упрочняющей обработки деталей в среде стальных шаров

Introduction. The research results of the vibration part processing in the steel balls medium are provided. Technological capabilities of the treatment are identified. The concept of process reliability is considered. Factors affecting the output parameters of a (process) control object from the point of view of its reliability, and indicators for estimating the process reliability are determined. Materials and Methods. As an object for the reliability research, the vibration finishing-strengthening processing in the steel balls medium is selected. This process can be performed on the part hardening and finishing operations, peening, and coating (galvanic, paint, rubber, adhesive, etc.) preparation of parts. Samples from various materials applied in machine industry and instrument-making are used. Research Results. A set of models for forming process reliability indices that allow providing increase in efficiency and reaching the specified value and stability of quality parameters of the processed part is obtained. Dependences for the determination of arithmetic average surface roughness, hardening depth, deformation ratio, and cutting time, are determined. A set of pilot studies which results confirm adequacy of the theoretical dependences is carried out. Discussions and Conclusions. A set of the obtained models can help to calculate the accuracy factor value at the stage of process design that will allow predicting reliability of the process accepted for production.

An adaptive control system for a shell-and-tube heat exchanger

This article suggests an adaptive control system for a hydrocarbon perspiration temperature control. This control system consists of a PI-controller and a pseudolinear compensating device that modifies control system dynamic properties. As a result, the behaviour research of the developed temperature control system has been undertaken. This article shows high effectiveness of the represented adaptive control system during changing control object parameters.

Tracking error sensitivity in a relay system operating in the forced oscillation mode

Relay systems with two-position relay element and a smooth nonlinear control object operating in the forced oscillation mode are considered. A discrete linearization of such systems was proposed and based on it a method of determining the sensitivity function of the tracking error to the change of the control object's parameters was developed. The method can be used to study the sensitivity of systems with symmetric pulse-width modulation that are widespread in engineering. The example illustrating obtaining the sensitivity function is presented.

Design concepts of adaptive electromechanical control systems with reference models

Design concepts of tracking adaptive electromechanical control systems of limit speed with the use of reference models ensuring adaptation both to the change of the control object parameters and certain changes in the environment are considered. The functional structure of electromagnetic systems with reference stationary models and signal self-adjustment supported by digital adapters, as well as specifics of their synthesis providing implementation of two control rates, is considered. For adaptation to parameters of external influence and, as a result, to the modes of functioning of an electromechanical control system within the zones of “small” and “large” coordinate deviation, the functional structures of the servo electric drives are supplemented by adaptive reference models installed at the input of the closed control systems and serve as a specific power-up sensor. Results of simulation modelling of the electromechanical system with the adaptive reference model in the Matlab/Simulink environment confirming the effectiveness of the proposed approaches are given.

Synthesis of searchless adaptive system based on lyapunov function using state observer

Searchless adaptive control system was studied and synthesized based on a Lyapunov function by a transient object under noisiness of measured values using state observer. The system adapts to the control object, regardless of whether the control object has static or dynamic characteristics. Additionally, the noise effect on the adaptive system behavior in the long run was investigated. The designed adaptive inference correction controller allows to adjust the control object inference and eliminates the static error of inference. State observer, which is based on the reference model restores the control object state vector. Even with significant object root deviations and random variables, adaptive system adapts the control action values and sets the control object inference to the desired value with the desired transition process time. The model was developed in the MATLAB/Simulink software package. Based on simulation, study of efficiency of the proposed model with different changes in the control object parameters was carried out.

WORKBENCH FOR CONTROL SYSTEMS TRIALS BASED ON VIPA 300 CONTROLLER AND ADVANTECH INPUT/OUTPUT CARD

The topic is about workbench creation for control systems trials based on VIPA 300 industrial PLC and model of control object which is implemented in MatLab Simulink program on PC. Connection between controller and the PC is provided by the Advantech PCI-1711 input/output card of discrete and analog signals. Object identification, control system synthesis, creation of control device structure and its parametrical identification, as a rule, is done on a PC in a modelling environment, e.g. in MatLab. But often, using this PC modelling, the hardware and software features of algorithms which were obtained during system synthesis are not considered in a specific industrial PLC. It is considered a good idea to use a composite version where obtained algorithms are tested in a real industrial PLC and control object is substituted by a model which is working on a PC in real time scale. In this case software realization of algorithms in a specific PLC are fully taken into account and substitution of real control object by its model considerably reduces the costs for carrying out experiments and allows to study the system behavior when control object parameters and modes of operation vary greatly. The creation of workbench stipulates several stages: configuration and programming of industrial PLC VIPA 313 SC, installation and configuration of Advantech PCI1711 input/output card, tuning of Simulink modelling environment for working in real time scale using Real-Time Windows Target Library, testing of workbench by using constant and harmonic signals of different frequencies. Work results of virtual stabilization system are compared with combined version. In virtual stabilization system PID governor and control object are implemented in Simulink. In combined version control object is still implemented in Simulink and PID governor - in VIPA 313 SC controller (using functional block FB58 from Step7 standard library).