Robust PID Design for a Servosystem Using mu Synthesys in MATLAB
Asparuh G. Markovski

Abstract

Robust PID design via μ synthesis for a laboratory model of a servo system manufactured by the Polish company Inteco is done. The main goal is to demonstrate the new potentials of the Robust Control Toolbox for MATLAB for tuning fixed structure controllers for objects with an uncertainty, introduced in year 2021. Thus, the new version of musyn function can be used for both “classical” non-parametric and parametric robust control synthesis. Here the controller is constructed as a tunablePID object, and the system has both uncertainty and tunable parameters (genss object). The control objectives are given as in the usual mu synthesis approach – in the frequency domain using penalty filters. Some of the model parameters are modelled with a structured uncertainty. Additionally, unstructured uncertainty is introduced due to the presence of nonlinearity of gap type. For both cases different PID controllers are tuned. Simulation experiments are performed with the model. The operability of the created regulator is tested on the experimental installation.

Keywords
Robust Control, mu synthesis, PID

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DOI: 10.47978/TUS.2022.72.02.001
 

Electroplating Plant Control System
Georgi Ruzhekov

Abstract

The system is designed to control a line for chrome plating of large machine elements. Chrome plating provides corrosion protection, increases surface hardness and improves the wear resistance of parts. All processes are controlled - transfer of parts, control of galvanizing current, temperature control of electrolyte solutions, safety and other auxiliary functions. The control system is based on a Prog-rammable Logic Controller (PLC) and the necessary signal modules. Decentralized peripherals with wireless industrial PROFINET communication of mobile objects were also used. The control of the main drives is performed with inverters with PROFINET communication, and for those of the mobile objects - wireless PROFINET communication. The service staff uses two pcs. 12“touch operator panels - for the charging station and for service support. The operators also have a SCADA system, from which the installation can also be controlled, as well as set additional parameters.

Keywords
Chrome plating, Industrial control system, PLC, SCADA.

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DOI: 10.47978/TUS.2022.72.02.002
 

Modeling and Control of Rectification Column
Ahmed Kula, Anna Georgieva and Georgi Ruzhekov

Abstract

Paper introduces modeling and control of rectification column. The modeling of process is important part of engineering, because it gives an overview of dynamics of the process. In chemical industry most of the processes are involved in purifying liquids. One way to purify liquids is to use rectification process. Rectification process is multiple distillation. Multidisciplinary system is being created for modeling and control of rectification process by desired product. The plant is realized in MATLAB. For this purp ose, is created software in AppDesigner. Simulation of process is made in Simulink and after that the parameters of the process are transferred to PLC system. The control system uses an industrial controller and SCADA system. In this work are realized two ways of control for rectifying process – PID and PID with decoupler matrix. Communication between the two products (MATLAB and PLC/SCADA) is created through industrial protocol – MODBUS. Programmer logic controller (PLC) is MODBUS master and software developed in AppDesigner is MODBUS slave.

Keywords
Multidisciplinary system, rectification, control system, PLC, SCADA, MATLAB, MODBUS.

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DOI: 10.47978/TUS.2022.72.02.003
 

Design and Investigation of Аdaptive Fuzzy Level Control System for Carbonisation Column
Milen Slavov

Abstract

The aim of this research is the design of PID Sugeno fuzzy logic controller (FLC) for the control of level in carbonisation column for the production of soda ash, without using a model of the process and with online fuzzy adaptation of its parameters. The controller is developed on the basis of a PD FLC with inputs the system error and its derivative, a parallel integrator of error and a Sugeno module for online tuning of the parameters according to the measured level or its reference. The adaptive FLC is implemented in a programmable logic controller for real time control. The closed loop system is investigated by experiments in industrial environment and an operating carbonisation column. The designed system reduces the mean squared error and the control variance. It also compensates the industrial disturbances and the changes in the process, and prolongs the life of the final control elements.

Keywords
Fuzzy control, Level control, Adaptive systems, Takagi-Sugeno model, Control design.

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DOI: 10.47978/TUS.2022.72.02.004
 

Abstract

Memristor elements are innovative and nano-dimension electronic nonlinear two-terminal components with memory effect, and have potential application in various electronic circuits, like memory devices, neural nets, digital and analog reconfigurable schemes, which engineering involves accurate and simplified models. In this work, a modified and better-quality model for metal oxide-based memristor elements is presented, to be applied for primary design of memristor-based analog filters. The presented memristor model has a high correctness, simple mathematical equations and sensitivity thresholds. Its LTSPICE library model is created and used for investigations of low-pass and high-pass analog filters. The offered memristor model suitably represents the nonlinear dopant motion. The corresponding voltage-current and state-flux relations are analyzed for both hard-switching and soft-switching regimes. The conducted analyses and computer simulations approve its proper operation in electronic devices, expressing the basic and important fingerprints of memristor components.

Keywords
Metal oxide-based memristors, nonlinear dopant drift, sensitivity thresholds, LTSPICE model, filters.

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DOI: 10.47978/TUS.2022.72.02.005
 

A Metal Oxide Memristor-Based Oscillators and Filters
Stoyan M. Kirilov and Ivan D. Zaykov

Abstract

Memristors are novel and nano-sized electronic passive elements with memorizing properties, potentially applicable in different electronic schemes, as neural networks, memory circuits, analog and digital devices, which design requires precise and simple models. In this paper, a modified and improved model of metal oxide memristors is proposed, in order to be used for preliminary engineering of memristor-based generators, filters and other electronic circuits. The offered model has a high accuracy, simplified math expressions and includes activation thresholds as well. Its corresponding LTSPICE library model is generated and applied for analysis of oscillators, low-pass and high-pass filters. The suggested model correctly expresses the nonlinear ionic dopant drift. The basic current-voltage and state-flux relationships are analyzed for both soft-switching and hard-switching modes. The conducted analyses and simulations confirm its correct operation in electronic circuits, representing the main fingerprints of memristor elements.

Keywords
Metal oxide memristors, nonlinear ionic dopant drift, activation thresholds, LTSPICE library model.

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DOI: 10.47978/TUS.2022.72.02.006

System for Monitoring and Analysis of Environmental Data
Antonia L. Pandelova, Svetlin I. Vladov, Nikolay S. Stoyanov and Bozhidar P. Dzhudzhev

Abstract

Most of the employees in the office have no idea what health risks the work environment hides for them. It is important to maintain a healthy working environment in the office, as this can reduce the absence of sick staff and their good tonus can be maintained. An environmental data monitoring and analysis system has been developed, which includes a particulate matter sensor, a light sensor and a temperature sensor. The system includes three main units - sensor part with three different sensors, Arduino Nano sensor communication platform and web server for communication with which the Linux operating system is used. The necessary settings have been made for reading data from the sensors, converting them into digital form, storing them in a database and graphical visualization of the measured values. When visualizing the measurements, the period of visualization can be chosen - from the last hour to one year ago. The developed system has been tested for monitoring the environment of a real object.

Keywords
Database, Light sensor, Linux, NOVA SD011 Sensor, Temperature sensor

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DOI: 10.47978/TUS.2022.72.02.007

Discrete Wiener Filter Application in Wind Turbine Control
T. Puleva, O. Ognyanova, E. Haralanova

Abstract

Discrete stochastic control algorithms for wind turbine generators based on Wiener filter theory are explored in this paper. This approach is very effective in operation in a tracking regime. A discrete controller is designed by taking into attention functional and magnitude constraints. The application of Wiener filter design permits to extend the problems range: extrapolation of the input signal and controller direct design based on Diophantine equation instead of functional constraints in the classical design method. This approach simplifies the design procedure. The frequency characteristics of the optimal system and of the controller by variable wind speed are analyzed. The system performance is investigated in the frequency domain as well as by the error standard deviation under variable wind speed.

Keywords
Wind turbine, tracking regime, Discrete Wiener filter, functional and magnitude constraints, direct design based on Diophantine equation

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DOI: 10.47978/TUS.2022.72.02.008