Synthesis Of Control Systems Research Articles

РАЗРАБОТКА МЕТОДОВ И СРЕДСТВ УПРАВЛЕНИЯ АЭРОГАЗОДИНАМИЧЕСКИМИ ПРОЦЕССАМИ НА ДОБЫЧНЫХ УЧАСТКАХ

The practical development of the algorithm for optimal control of mine ventilation was preceded by comprehensive studies of the specific features of mining sites in order to obtain their mathematical description. The latter includes the static and dynamic characteristics of objects, i.e. the relationship between input and output values. The purpose of the research: to develop methods and management tools aerogasdynamics processes on mining sites of coalmines. Research methods. The methodology based on the system approach; modern methods of mathematical statistics, decision theory; mathematical logic devices; factor analysis; mathematical modeling; set theory and system analysis. To determine the dynamic characteristics of aerogasodynamic processes, experimental methods were used, divided into active and passive. The active method consists in con-structing a dynamic model of airing objects by approximating the transition curve obtained because of special effects on the airing object with an analytical expression. Statistical dynamics methods were used to obtain dynamic characteristics based on normal operation data. The method of correlation analysis was used. Results of research: experimental verification showed that the maximum relative error of in determining the methane concentration from the static characteristic constructed using a modified technique does not exceed 10 %. The value of the error was determined by comparing the static characteristic obtained by the modified correlation analysis method with the exact static characteristic of the airing object. The latter were found with regard to dynamic properties of the object and additive structures aerogas dynamics processes. Conclusion. The method of correlation analysis can be used to determine the dependence of the methane flow rate on the airflow rate in the steady-state mode, i.e. the static characteristic q = f (Q) for the site and lava. To determine the static characteristics based on the data of normal operation with a limited observation interval (5-10 days), a modified method of correlation analysis is proposed. Small values of the relative error of indicate the possibility and feasibility of using a modified correlation analysis technique to construct a static characteristic of the airing object based on random processes of methane concentration and air flow obtained during normal operation of the site. The static characteristics C= f (Q) and q= f(Q) are widely used to determine the mathematical expectations of the methane concentration and flow rate of mining sites, in the modeling of ventilation facilities and in the analysis and synthesis of mine ventilation control systems.

MODELING A FLUID POWER DRIVE OF THE EXCAVATOR EQUIPMENT

Problem. The hydraulic drive of modern construction and road machines is quite complex, and it takes a lot of time and effort to model the entire drive in full. However, improving the quality of design with reducing terms and costs becomes possible only with the use of modern technologies, computer hardware and software. The existing models of hydraulic system working processes in the physical modeling environment SimHydraulics are presented by block diagram layouts from standard library elements (slide valve, hydraulic pump, hydraulic cylinder, safety and reverse valves, hydraulic locks, etc.). However, they do not consider the influence of time-varying external forces, which are a reaction during transient processes in multi-link mechanical systems. Goal. The aim of the work is to develop a simulation model of the fluid power drive of the excavator working equipment mechanical system in the MATLAB & SimHydraulics package for studying the dynamics of transient processes of multilink mechanical objects. Methodology. The article describes an example of developing a physical simulation model of the excavator working equipment fluid power drive in the SimHydraulics package. Using the real technical characteristics of the hydraulic equipment of the Borex 2201 excavator, the performance of the developed model was checked and the power characteristics of the actuators were determined. Originality. Using the blocks described in the article, a simulation model of the interaction of the excavator working equipment mechanical system with its fluid power drive can be created. Practical value. The model proposed makes it possible to obtain values characterizing transient processes, including changes in the value of the generalized coordinates of the characteristic points in the working equipment, the rate of their change, and the effort in the hydraulic cylinder. A visual representation of the manipulator movement can be obtained using the SimScape built-in visualization function. The resulting model allows solving problems of analysis and synthesis of excavator operation control systems.

Two-Loop System with Reference Model for Control of Spatial Movement of Cargo Underwater Vehicle

Currently, autonomous underwater vehicles (AUV) are increasingly used to perform tasks related to the maintenance of underwater communications and various underwater production complexes, as well as performing underwater technological operations. To effectively perform these operations, AUV must have high-quality control systems that will ensure their accurate movement both along long spatial trajectories formed during their movement to the objects of work, and when performing complex maneuvers near underwater infrastructure objects. At the same time, the main difficulty that arises in the process of synthesis of AUV control systems is the significant non-linearity of the dynamic models of these control objects, the presence of interactions between their degrees of freedom, as well as the uncertainty and variability of their parameters. In this paper, we propose a method for synthesizing the spatial motion control system of the AUV, which allows us to take into account these negative effects. This system contains two loops. The first loop includes a combined system containing a nonlinear controller to achieve the desired dynamic characteristics of the AUV, when its parameters are equal to the nominal values, and a controller with self-tuning according to the reference model, which provides compensation for an unknown or variable part of the parameters. In this case, the parameters of the controller with the reference model are selected to reduce the possible amplitude of the discontinuous signal for controlling the AUV velocity. The second loop is a non-linear position controller that allows to take into account the dynamic properties of the velocity control loop and the kinematic properties of the AUV. The advantage of the proposed control system in comparison with traditional ones based on PID controllers is a higher control accuracy when moving along complex spatial trajectories, regardless of changes in the AUV parameters. The simulation results confirmed the high efficiency of the synthesized two-loop control system.

Approximate optimal synthesis of operational control systems for dynamic objects based on quasilinearization and sufficient optimality conditions

A new approach to the analytical design of linear and nonlinear integrated automatic control systems (ACS) of a real (accelerated) time scale, based on the joint use of dynamic programming technologies and the quasilinearization method, is presented. For continuous dynamic systems, the foundations of the theory of nonlinear synthesis in a degenerate (synergetic) formulation are given.

INFORMATION TECHNOLOGY FOR SYNTHESIS AND OPTIMIZATION OF FUZZY SYSTEMS RULE BASES

In the last two decades, intelligent computer systems based on fuzzy set theory, fuzzy logic and soft computing are widely used in various fields of science and technology to solve problems of control, identification, modeling of complex physical and economic phenomena, classification, pattern recognition, etc. Modern research in the field of creation and development of fuzzy systems (FS) of control and decision-making is conducted mainly in the direction of development of highly effective methods and information technologies of their synthesis and structural-parametric optimization. This paper is devoted to the development and research of information technology for the synthesis and optimization of highly efficient rule bases (RB) with the optimal set of consequences and optimal number of rules for Mamdani-type FSs in terms of incomplete source information. The developed information technology allows to conduct iterative search of the optimal vector of RB consequences based on a sequential search of the consequences of each rule, as well as to identify and exclude rules from RB, that do not affect the system operation, to reduce the total number of rules to optimal. To study the effectiveness of the proposed information technology in this work, the synthesis and optimization of the fuzzy automatic control system (ACS) for the multi-purpose mobile robot (MR), which is able to move on inclined and vertical ferromagnetic surfaces, is carried out. The obtained results of computer simulation showed that the fuzzy ACS of MR with optimized RB based on the developed information technology has higher quality indicators of control compared to the ACS with a similar RB developed on the basis of experts knowledge. Also, the optimized RB by means of the proposed information technology has fewer rules than the full RB, which is synthesized on the basis of experts knowledge, which, in turn, significantly simplifies the further software and hardware implementation of the developed fuzzy ACS of MR. In addition, in the process of synthesis and optimization of the RB for the fuzzy ACS of MR, presented information technology did not require significant computational costs, which generally confirms its high efficiency and feasibility of application to design rule bases of control and decision making FSs of different types.

Modeling the stress-strain state of crane metal structures

The intensification of construction production imposes very strict requirements on the safety of construction machines. When carrying out lifting and hoisting operations using overhead cranes, production safety is primarily determined by the technical condition of the undercarriage and crane runways, as well as metal constructions. The authors deal with the issues related to modeling and research of the stress-strain state of metal structures of an overhead crane. A model of the crane metal structure is proposed, which includes the main and end box-section crane girders. To study possible geometric movements of the crane, a model of an overhead crane was designed in KOMPAS-3D software environment. The model contains main and end box-section girders. The model allows determining the maximum possible misalignment of the crane and runout of one of the sides. To determine the bending, tensile and compressive stresses in the bridge truss and the deformations of the crane metal structures, depending on the working loads, a 3D model of the bridge crane was created in the ADW Winmachine software environment. With its help, the bending stiffness of the crane bridge was established. These values are necessary to compile a mathematical model of an overhead crane as a control object in the synthesis of an automatic control system.

The synthesis of control system to synchronize ship generator assemblies

This paper considers the construction of principles and the synthesis of a system of effective control over the processes of synchronization of generator sets (GSs) that form a part of the distributed MP-control systems for complex ship technical systems and complexes (STS and C). The tasks of synchronization have been set, the process and database models have been built, the system configurations have been defined. Based on the use of resultant functions, we have determined stages in solving the tasks of control over the frequency adjustment synchronization in a hierarchical sequence. The performance analysis of the STS and C control elements has been carried out; the use of the integrated optimization criteria and dual management principles has been proposed. Practical techniques to manage the GS synchronization have been given. We have solved the problem of high-speed control over the frequency of synchronized objects based on the principles of adjustment. That has made it possible to determine in advance the moments of GS enabling under the deterministic and stochastic statement of the synchronization task. The results of the experimental study into the GS synchronization processes are given; the effectiveness of the proposed GS control has been proven. The principles underlying the construction of procedures to control the GS composition when using the methods of "rigid" and "flexible" thresholds have made it possible to define the optimization criteria and implement a control law that satisfied the condition for an extremum, which is an indicator of the feasibility of the set goal and takes into consideration the limitations of control influences. We managed to design a system in the class of adaptive control systems by the appropriate decomposition of the system's elements by splitting a synchronization task into the task on performance and the task on control under the required conditions. The given examples of the processes where the synchronization failed while using standard synchronizer control algorithms, as well as processes of successful GS synchronization when applying the proposed synchronizer dual control algorithms, have confirmed the reliability of the main scientific results reported here.

Об использовании нейронных регуляторов

The application of neural networks for the synthesis of control systems is considered. Examples of synthesis of control systems using methods of reinforcement learning, in which the state vector is involved, are given. And the synthesis of a neural controller for objects with an inaccessible state vector is discussed: 1) a variant using a neural network with recurrent feedbacks; 2) a variant using the input error vector, where each error (except for the first one) enters the input of the neural network passing through the delay element. The disadvantages of the first method include the fact that for such a structure of a neural network it is not possible to apply existing learning methods with confirmation and for training it is required to use a data set obtained, for example, from a previously calculated linear controller. The structure of the neural network used in the second option allows the application of reinforcement learning methods, but the article provides a statement and its proof that for the synthesis of a control system for objects with three or more integrators, a neural network without recurrent connections cannot be used. The application of the above structures is given on examples of the synthesis of control systems for objects 1/s2 and 1/s3 presented in a discrete form.

Adaptive Position/Force Control of a Robotic Manipulator in Contact with a Flexible and Uncertain Environment

The present paper concerns the synthesis of robot movement control systems in the cases of disturbances of natural position constraints, which are the result of surface susceptibility and inaccuracies in its description. The study contains the synthesis of control laws, in which the knowledge of parameters of the susceptible environment is not required, and which guarantee stability of the system in the case of an inaccurately described contact surface. The novelty of the presented solution is based on introducing an additional module to the control law in directions normal to the interaction surface, which allows for a fluent change of control strategy in the case of occurrence of distortions in the surface. An additional module in the control law is perceived as a virtual viscotic resistance force and resilient environment acting upon the robot. This interpretation facilitates intuitive selection of amplifications and allows for foreseeing the behavior of the system when disturbances occur. Introducing reactions of virtual constraints provides automatic adjustment of the robot interaction force with the susceptible environment, minimizing the impact of geometric inaccuracy of the environment.

An aggregation decomposition for the analysis and synthesis of spacecraft control systems

This paper focuses on the interconnections between the variants of assembling the elements of spacecraft control systems within the considered alternative graphic formalization approach. Under these circumstances, the assembly variants of the system elements or their sets are depicted as peaks of an alternative graph, with arcs representing interconnections. The aggregation decomposition method in the analysis and synthesis of the structure of complex systems includes two interrelated stages: sequential decomposition of objectives, functions, tasks, etc., performed by the system, and their aggregation at appropriate detail levels.

Mathematical model of the extraction of vegetable oil by an organic solvent

A mathematical model of the process of extraction of vegetable oil by an organic solvent for a separate section of the extractor with irrigation has been developed. The model is intended for the synthesis of an automatic control system. A description of the change in the oil concentration in the oilcake along the length of the extraction section and in the miscella for a steady-state operation is obtained. And a system of independent differential equations with a delayed argument is obtained that connects deviations from the nominal oil concentrations in the oilcake and miscella at the outlet of the section with flow deviations and oil concentrations at the inlet of the section. The transition from partial differential equations to equations with a delayed argument will reduce the time spent on calculating the adjustable parameters of the control system during its synthesis.

DEVELOPMENT OF AN AUTOMATIC CONTROL SYSTEM FOR THE FLOTATION PROCESS OF POTASSIUM CHLORIDE

The article discusses the creation of an algorithm and the synthesis of a two-loop automatic control system for level and density, instead of the current single-loop one. Aim. Density stabilization and stabilization of the flotation machine power supply by creating a two-circuit automatic level and density control system in order to improve the quality of the final product. Materials and methods. Since there is no net lag in the system, the controller is tuned using the parametric optimization method, namely: according to the criteria of modular (MO) or symmetric optimum (CO). The MO/CO criterion is also used to adjust the contour. All automatic control systems are obtained in the MATLAB Simulink software package. Control quality is measured by metrics such as transient time, overshoot, and system error. The first two indicators show the dynamics of the process, and the last indicator shows the accuracy of the system. Conclusion. The finished two-loop automatic control system, developed in the software package MATLAB Simulink, according to the analysis of the obtained process parameters, provides stabilization of the density and level in the agitation tank for flotation.

VECTOR CONTROL ALGORITHMS FOR AN ELECTROMECHANICAL UNBALANCE VIBRATION MODULE WITHOUT PRELIMINARY MAGNETIZATION OF THE ASYNCHRONOUS MOTOR

With the development of electronic systems, the control of various asynchronous type electric motors is becoming more efficient and accurate. Such engines are used everywhere in the world, the variety of tasks performed by such mechanisms is growing every day, and the need for them is not decreasing. Nowadays, AC electric drive systems based on an asynchronous motor are becoming more widespread. This is due to the high reliability, simple design and relatively low cost of induction motors, as well as the rapid development of power converter technology, which makes it pos¬sible to create various types of semiconductor converters and reliable power supplies. In most cases, the vector control system is built for a pre-magnetized electric drive. This article discusses the synthesis of a vector control system for an asynchronous motor without preliminary magnetization, and also considers algorithms for vector control of an electromechanical unbalanced vibration module without preliminary magnetization of the asynchronous motor. Aim. To develop a control structure for an asynchronous motor of an unbalanced vibration module. Introduce a division link into the management structure. Synthesize a speed controller, rotor flux linkage and two components of the stator current. Compensate for the EMF action in the channels of the transverse and longitudinal axis. Provide the control system with the ability to reverse the electric machine. Implement the simulation of the resulting system and conduct a study of the results obtained, having obtained dynamic characteristics. Methods. The vector control system is constructed in the form of a stabilization channel of the rotor flux linkage module and a channel for controlling the rotor rotation speed. To achieve the desired result, we introduce a nonlinear regulator of the division link type into the control structure. This will convert the nonlinear structure to linear. Let's compensate the EMF action in the channels of the transverse and longitudinal axis. Having realized the simulation of the obtained system, we will conduct a study of the results obtained, having obtained dynamic characteristics. Results. Structural modeling was carried out in the MATLAB/Simulink software package. For the purpose of a comparative assessment of the synthesis results of a control system with a torque regulator in the form of a division link, a subordinate control system will also be synthesized, which has similar parameters of the power unit. Conclusion. The choice of the motor torque as the output coordinate makes it possible to significantly simplify the mathematical model of the induction motor. In addition to the features of the mathematical model of an asynchronous electric motor, in this work it is necessary to take into account the features of the vibration module as a load. In this case, two main features can be distinguished – a large moment of inertia of the flywheel masses of the electric drive, as well as a sinusoidal dependence of the moment of resistance on the angle of rotation of the rotor.

Autonomous wheeled mobile robot maneuvering in constraint environment. Trajectory tracking quality criteria

In this article the problem of control system synthesis for differential drive wheeled mobile robots operating within constraint environment is considered. The proposed approaches of solving trajectory tracking problem take into account the geometric features of both the robot and the transported cargo. The collision avoidance problem is solved at the controller level, without any changes to the planned trajectory. Three approaches are proposed: minimizing the distance to the trajectory, minimizing the distance to the reference position, and maximizing the distance to obstacles. In these approaches the constant analysis of position of each point of robot’s body outline contour is used. Negative influence of the position of these points on qualitative trajectory pass is represented in vector form. For each of the approaches formalized tracking quality criteria are determined, methods of implementation of control systems and controllers taking into account these criteria are proposed. The part of the control signal responsible for taking into account geometry of the robot and avoiding collisions is defined via the force-moment vector representation. Results of simulation modeling prove the efficiency of the proposed approaches. A comparison of the proposed approaches is presented. Potential ways of more efficient use of these approaches are given.

Sliding mode control for networked control systems: A brief survey

In recent years, the control synthesis and analysis of networked control systems (NCSs) have attracted increasing attention from both industrial and scientific communities, and many contributions have been published. With the development of advanced control theories, it has become a trend to combine networks with control systems. As a specific nonlinear control method, due to its complete robustness on the sliding mode surface, sliding mode control (SMC) becomes an effective means to solve the uncertainties and nonlinear characteristics in NCSs. In this paper, a review of the recent advances and challenges of SMC in NCSs is given. Firstly, a brief introduction to NCSs is given and the essential technical constraints are also summarized. Then, the results of the SMC applied to NCSs with basic constraints, including packet dropouts, time delays and signal quantization are given in details. Finally, some concluding remarks are made and several potential future research topics are discussed.

МЕТОДЫ СИНТЕЗА РЕГУЛЯТОРОВ ДЛЯ ГИДРОДИНАМИЧЕСКИХ СИСТЕМ УПРАВЛЕНИЯ С РАСПРЕДЕЛЕННЫМИ ПАРАМЕТРАМИ

An important problem of choosing a method for synthesizing regulators for constructing a system for controlling the parameters of hydrolithospheric processes is considered. The article deals with the issues of system analysis and synthesis of control systems with distributed parameters. The existing ways of solving mathematical equations describing models with spatial coordinates are shown. The main methods when there are solutions to the mathematical model are identified: analytical construction of optimal regulators and the structural method of analysis. Methods of approximation in cases where there is no solution to the mathematical model are described: methods of finite-dimensional approximation; decomposition of bilinear control systems; frequency method. The main provisions of the methods for solving the problem of discretization in partial derivatives are given. The preference of the frequency method of regulator synthesis in the creation of control systems for hydrolithospheric processes is shown. A hodograph is obtained in the form of logarithmic amplitude and phase frequency surfaces, which can be used to interpret the Nyquist stability criterion from graphs. A frequency method for the synthesis of multidimensional systems is considered, when the input effects to a distributed controller are implemented as a discrete function in space. The condition under which the object belongs to the class of spatially invariant objects is shown. It is concluded that the frequency method of regulator synthesis is the most convenient tool for creating systems with distributed parameters.

Mathematical models of control in Digital Economy platforms

The article examines the problems of the functioning of economic systems in which production, distribution, exchange and consumption are carried out on the basis of digital technologies. These circumstances stimulate the creation of new economic models of interaction and management, corresponding to new information opportunities at different levels of the organizational structure of economic systems. Along with the arrays of deterministic data at the disposal of independent economic agents and management structures, there are representative volumes of data on the implementation of uncontrollable factors. Particular interest in the work is shown in agricultural technologies, which, along with the volatility of demand for products, are characterized by indefinite natural fluctuations, which requires the development of special models and specific mechanisms for coordinating activities. A series of different economic models is presented, reflecting the possibilities of creating coalitions of active agents. The issues of centralization and decentralization in the management of economic systems are also fundamental. For the analysis and synthesis of control systems, a spectrum of models of the functioning of economic agents is presented, for which various forms of information and various classes of behavior strategies are available.

A new two-step approach for solving a control system synthesis problem by symbolic regression methods

The problem of synthesizing a control system using symbolic regression methods is considered. A new approach suggested in this work considers the control system synthesis problem as the set of optimal control problems and suggests a two-step algorithm to solve it. At the first step evolutionary algorithms are used to solve the optimal control problem numerically for each initial state from a given domain. As a result of the first step a set of optimal trajectories is obtained. At the second step symbolic regression methods are considered to solve the problem of approximating the found in the first step set of trajectories optimally. The result of the second step is a solution of the control system synthesis problem as a multidimensional control function of object’s state vector. Compared to the known approach to solve the control system synthesis problem using symbolic regression methods, the suggested approach provides betters results since the search of control function is carried out based on the set of optimal trajectories. Computational experiment presents the solution of the applied problem of synthesizing the optimal control system for the spacecraft landing on the Moon. It is experimentally demonstrated that the synthesized control system provides a close to optimal landing trajectory for any initial state from a given domain.

Synthesis of non-stationary continuous nonlinear control systems by the generalized Galerkin method

Synthesis of non-stationary continuous nonlinear control systems by the generalized Galerkin method

Исследование управляемости билинейных систем с ограниченным управлением

Optimal control is closely related to the choice of the most advantageous control modes for complex objects, which are described using ordinary differential systems. The problem of optimal control consists in calculating the optimal control program and synthesizing the optimal control system. This problem arises in the applied field of the optimal control theory, in the case when control is based on the principle of feedback and in automatic control systems. Optimal control problems, as a rule, are calculated by numerical methods to find the extremum of a functional or to solve a boundary value problem for a differential equation system. From a mathematical standpoint, the synthesis of optimal control systems is a nonlinear programming problem in functional spaces. In this study the problem of complete controllability of a bilinear control system on the plane was considered. The controllability of bilinear systems with both unlimited and limited control was studied. The evidences of closed trajectory systems controllability theorems were produced. The authors have defined multiple criteria of complete controllability for bilinear system with limited control. The complete controllability conditions of bilinear control system have been proposed with their algebraic reasoning. In the contemporary context of universal robotization of production, completely controllable systems matter in navigation, as well as in modeling of a number of economic and social processes.