scholarly journals POSSIBILITIES OF CYBER-PHYSICAL APPROACH TO STUDYING FREQUENCY PROPERTIES OF CLOSED SYSTEM WITH INCOMPLETE INFORMATION ABOUT CONTROL OBJECT MODEL

2021 ◽  
Vol 2021 (4) ◽  
pp. 21-34
Author(s):  
Elena Georgievna Krushel ◽  
Ekaterina Sergeevna Potafeeva ◽  
Tatyana Petrovna Ogar ◽  
Ilya Viktorovich Stepanchenko ◽  
Ivan Mikhailovich Kharitonov
Keyword(s):  
Transfer Function ◽  
Incomplete Information ◽  
Closed System ◽  
Control Object ◽  
Optimization Procedure ◽  
Frequency Characteristics ◽  
System Stability ◽  
Object Model ◽  
Physical Approach ◽  
Frequency Properties

The article considers a method of reducing the time spent on the experimental study of the frequency properties of an object with an unknown mathematical model by using the cyber-physical approach to the automation of the experiment. Nonparametric estimates of unknown frequency characteristics of an object are received from experimental data on the reaction of the object's output to the input harmonic signal in the form of a mixture of sinusoidal signals of different frequencies. To divide the output signal into components corresponding to each frequency, a computer technology is used that implements an optimization procedure for finding the values of both real and imaginary frequency characteristics, according to the frequencies represented in the harmonic input signal. The method is also suitable for accelerated evaluation of the frequency characteristics of an object with an unknown delay. There are considered the aspects of frequency properties estimation in the problem of closed system stability analysis, which is supposed to control an object with incomplete information about its model using a series-connected proportional-integral controller. The results of quick estimating the frequency characteristics of the object are used to identify the parameters of its transfer function. To solve the parameterization problem, there are used automation tools for calculating the transfer function according to data on the points of frequency characteristics implemented as part of the open-access computer mathematics system Scilab. There is given an example illustrating the possibilities of developing a control system using a reduced-order object model, as one of the applications of the results of parametric identification of the transfer function

A simulation study of nonideal mixing effect on the dynamic response of an exothermic CSTR with Cholette’s model

2021 ◽  
Vol 0 (0) ◽  
Author(s):  
Chane-Yuan Yang ◽  
Yu-Shu Chien ◽  
Jun-Hong Chou
Keyword(s):  
Transfer Function ◽  
Dynamic Response ◽  
The Other ◽  
System Stability ◽  
Mixing Effect ◽  
Characteristic Roots ◽  
Mixing Parameter ◽  
Perfect Mixing ◽  
And Control ◽  
Inverse Response

Abstract The study of nonideal mixing effect on the dynamic behaviors of CSTRs has very rarely been published in the literature. In this work, Cholette’s model is employed to explore the nonideal mixing effect on the dynamic response of a nonisothermal CSTR. The analysis shows that the mixing parameter n (the fraction of the feed entering the zone of perfect mixing) and m (the fraction of the total volume of the reactor), indeed affect the characteristic roots of transfer function of a real CSTR, which determine the system stability. On the other hand, the inverse response and overshoot response are also affected by the nonideal mixing in a nonisothemal CSTR. These results are of much help for the design and control of a real CSTR.

Robust Shape Optimization of Uncertain Dense Gas Flows Through a Plane Turbine Cascade

2011 ◽  
Author(s):  
Samuel J. Hercus ◽  
Paola Cinnella
Keyword(s):  
Robust Optimization ◽  
Shape Optimization ◽  
Flow Behavior ◽  
Computational Cost ◽  
Optimization Procedure ◽  
System Stability ◽  
Dense Gas ◽  
Turbine Cascade ◽  
The Mean ◽  
Inlet Conditions

A robust shape optimization procedure based on a multi-objective genetic algorithm coupled to a non-intrusive uncertainty quantification analysis was applied to a transonic inviscid flow of a dense gas over a plane turbine cascade. The goal was to simultaneously improve the mean turbine performance and the system stability under fluctuating thermodynamic inlet conditions. Despite an elevated computational cost, the optimization procedure was capable of generating a Pareto front of turbine geometries which improved the mean isentropic turbine efficiency μ(ηs) over the baseline profile, while limiting the solution variability in terms of the coefficient of variation of the power output CV(P2D). In addition to demonstrating an excellent parallel scalability over 1600 processors, the robust optimization revealed that variability of CV(P2D) depends more on the variation of inlet conditions than turbine geometry. A posteriori stochastic analyses on selected optimized turbine geometries allowed an investigation of flow behavior variability, as well as propositions for the improved selection of robust optimization cost criteria in future simulations.

scholarly journals Identification of Neural Network Model of Robot to Solve the Optimal Control Problem

2021 ◽  
Vol 20 (6) ◽  
pp. 1254-1278
Author(s):  
Elizaveta Shmalko ◽  
Yuri Rumyantsev ◽  
Ruslan Baynazarov ◽  
Konstantin Yamshanov
Keyword(s):  
Neural Network ◽  
Machine Learning ◽  
Mathematical Model ◽  
Optimal Control ◽  
Neural Network Model ◽  
Software Package ◽  
Control Object ◽  
Robotic Systems ◽  
Object Model ◽  
Modern Machine

To calculate the optimal control, a satisfactory mathematical model of the control object is required. Further, when implementing the calculated controls on a real object, the same model can be used in robot navigation to predict its position and correct sensor data, therefore, it is important that the model adequately reflects the dynamics of the object. Model derivation is often time-consuming and sometimes even impossible using traditional methods. In view of the increasing diversity and extremely complex nature of control objects, including the variety of modern robotic systems, the identification problem is becoming increasingly important, which allows you to build a mathematical model of the control object, having input and output data about the system. The identification of a nonlinear system is of particular interest, since most real systems have nonlinear dynamics. And if earlier the identification of the system model consisted in the selection of the optimal parameters for the selected structure, then the emergence of modern machine learning methods opens up broader prospects and allows you to automate the identification process itself. In this paper, a wheeled robot with a differential drive in the Gazebo simulation environment, which is currently the most popular software package for the development and simulation of robotic systems, is considered as a control object. The mathematical model of the robot is unknown in advance. The main problem is that the existing mathematical models do not correspond to the real dynamics of the robot in the simulator. The paper considers the solution to the problem of identifying a mathematical model of a control object using machine learning technique of the neural networks. A new mixed approach is proposed. It is based on the use of well-known simple models of the object and identification of unaccounted dynamic properties of the object using a neural network based on a training sample. To generate training data, a software package was written that automates the collection process using two ROS nodes. To train the neural network, the PyTorch framework was used and an open source software package was created. Further, the identified object model is used to calculate the optimal control. The results of the computational experiment demonstrate the adequacy and performance of the resulting model. The presented approach based on a combination of a well-known mathematical model and an additional identified neural network model allows using the advantages of the accumulated physical apparatus and increasing its efficiency and accuracy through the use of modern machine learning tools.

Research and Application of DDE Network Communication in Configuration Software

2013 ◽  
Vol 401-403 ◽  
pp. 1935-1938
Author(s):  
Yin Juan Zhang
Keyword(s):  
Control System ◽  
Data Exchange ◽  
Control Object ◽  
Configuration Software ◽  
Network Communication ◽  
Object Model ◽  
Dynamic Data ◽  
Interactive Interface ◽  
Theory Research ◽  
Research And Design

The network communication between MATLAB and configuration software is established using DDE(Dynamic Data Exchange) technology, which is easily to give full play to generate interactive interface in configuration software and simulation of control object model in MATLAB software. The calculation function of weakness in configuration software is repaired and the control object model and controller is to be isolated. The effective simulation platform for theory research and design of control system is established.

scholarly journals Analysis of the frequency characteristics of the control system for the processes of fuel supply to the cylinders of the power unit

2021 ◽  
pp. 9-16
Author(s):  
Anatoliy Borysenko ◽  
Oleksandr Yenikieiev ◽  
Dmitry Zakharenkov ◽  
Ihor Zykov
Keyword(s):  
Transfer Function ◽  
Computer System ◽  
Power Unit ◽  
Rotation Speed ◽  
Combustion Engine ◽  
Frequency Characteristics ◽  
Structural Diagram ◽  
Software Environment ◽  
Input Information ◽  
Discrete Transfer Function

The idea of monitoring the identity of the cylinder capacities of an internal combustion engine under conditions of incomplete information is proposed and a computer system is built on its basis. The signal of the instantaneous rotation speed of the crankshaft of the power unit was used as input information. In the development of the hardware architecture, injectors with piezoelectric actuators, the principle of direct digital control, and the principle of control with feedback on the state of fluctuations of the crankshaft rotation speed were used. The Laplace transform was used as a mathematical apparatus for analyzing the structural diagram of a computer system for programmed control of the processes of supplying fuel and air to the cylinders of the power unit. Mathematical models of the components of the hardware for controlling the processes of supplying the fuel-air mixture were constructed, and as a result of the analysis of the structural diagram of the computer system, the transfer function was obtained. Using the capabilities of the Matlab software environment, the transient and impulse transient characteristics of the system are obtained, the Nyquist hodograph is constructed, and the logarithmic amplitude-frequency characteristics of the hardware are established. It was found that the frequency characteristics of the mathematical model of a computer system have the necessary dynamic characteristics. Using the method of expansion into simple fractions, an expression is obtained for a discrete transfer function, the coefficients of the power polynomials of which are established using the method of determinants and computational capabilities of the Mathcad software environment. On the basis of a discrete transfer function, a scheme for computer modeling of the process of processing the signal of the instantaneous speed of rotation of the crankshaft by hardware is constructed. The output signal was obtained by computer simulation, as a result of the analysis of which the speed of the hardware for processing the input information was established.

Transfer Function Based Optimization of Film Hole Sizes With Conjugate Heat Transfer Analysis

2020 ◽  
Author(s):  
Sandip Dutta ◽  
Reid Smith
Keyword(s):  
Heat Transfer ◽  
Transfer Function ◽  
Transfer Functions ◽  
Optimization Technique ◽  
Leading Edge ◽  
Optimization Procedure ◽  
Metal Temperature ◽  
Heat Transfer Analysis ◽  
Maximum Temperature ◽  
Transfer Coefficients

Abstract With the improvements of 3D metal printing of turbine components, it is now feasible to produce ready to use production quality parts without casting and conventional machining. This new manufacturing technique has opened new frontiers in cooling optimizations that could not be practiced before. For example, it is now or in-the-near-future possible to have unconventional diameters of film holes. This paper seeks to optimize each film hole diameter at the leading edge of a turbine to achieve an optimum thermal objective. The design technique developed uses a transfer function-based learning model and can be used for both stationary and rotating airfoils. Proposed optimization procedure will also work on other parts of an airfoil; but our current analysis is limited to the leading-edge region. To apply this work on other critical regions, the corresponding heat transfer coefficients need to be implemented while building the transfer functions suitable for that specific component; however, the underlying optimization technique stays the same for any other component. Any optimization technique needs cost and benefit criteria. Cost is minimized in optimization to get maximum benefit with given constraints. In gas-turbine heat transfer, there is a ceiling constraint on maximum temperature that must be satisfied. This study minimizes the coolant flow with satisfying the constraints on average metal temperature and metal temperature variations that limit the life of turbine components. Proposed methodology provides a scientific basis for the sizing of film holes and is expected to decrease developmental cost of efficient thermal designs.

Research and Application of OPC Network Communication in Configuration Software

2013 ◽  
Vol 774-776 ◽  
pp. 1774-1777
Author(s):  
Yin Juan Zhang
Keyword(s):  
Control System ◽  
Control Object ◽  
Configuration Software ◽  
Network Communication ◽  
Control Technology ◽  
Object Model ◽  
Interactive Interface ◽  
Theory Research ◽  
Ole For Process Control ◽  
Research And Design

The network communication between MATLAB and configuration software is established using OPC (OLE for Process Control) technology, which is easily to give full play to generate interactive interface in configuration software and simulation of control object model in MATLAB software. The calculation function of weakness in configuration software is repaired and the control object model and controller is to be isolated. The effective simulation platform for theory research and design of control system is established.

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