______________________________________ III International Workshop on Modeling, Information Processing and Computing (MIP: Computing-2021), May 28, 2021, Krasnoyarsk, Russia EMAIL: isiddikov54@gmail.com (Isamiddin Siddikov); nodiramamasodikova@mail.ru (Nodira Mamasodikova); rodinaxon75@mail.ru (Odinaxon Rayimdjanova); holdav@mail.ru (Davronbek Khalmatov); mirzaaxmedova1961@gmail.com (Xuryat Mirzaaxmedova) ORCID: 0000-0001-9681-5156 (Isamiddin Siddikov); 0000-0002-7605-879X (Nodira Mamasodikova); 0000-0003-0333-7357 (Odinaxon Rayimdjanova); 0000-0002-2120-6257 (Davronbek Khalmatov); 0000-0002-2933-064X (Xuryat Mirzaaxmedova) © 2021 Copyright for this paper by its authors. Use permitted under Creative Commons License Attribution 4.0 International (CC BY 4.0). CEUR Workshop Proceedings (CEUR-WS.org) 64 Algorithms for synthesis of a fuzzy control system chemical reactor temperature Isamiddin Siddikov 1 , Nodira Mamasodikova 2 , Odinaxon Rayimdjanova 3 , Davronbek Khalmatov 3 and Xuryat Mirzaaxmedova 3 1 Tashkent State Technical University, 2, Universitetskaya street, Tashkent, 100095, Uzbekistan 2 Fergana branch of Tashkent University of Information Technologies named after Mukhammad al-Khwarizmi, 185, Mustaqillik street, Fergana, 150118, Uzbekistan 3 Tashkent Institute of Textile and Light Industry, 5, Shakhdjakhon street, Tashkent, 100100, Uzbekistan Abstract The issues of synthesis of a fuzzy control system for ill-defined technological processes are considered. An effective algorithm for the synthesis of a fuzzy logic controller and a fuzzy system for automatic regulation of the temperature regime of a chemical reactor, invariant to parametric and external disturbances, is presented. The proposed synthesis algorithm for a fuzzy-logical proportional-integral-differential (PID) -controller is simple and allows you to use a standard form of description of linguistic variables and a minimum set of control rules. The synthesized fuzzy logic controller gives the entire automatic control system the ability to maintain the reactor temperature at a given level in the presence of external disturbances, as well as to qualitatively control the technological process with a wide range of changes in its parameters over time. The used methods of the theory of fuzzy logic and neural networks allow you to operate with linguistic fuzzy statements. The bases of the rules of logical inference of a fuzzy-logical regulator in the form of a Cartesian product of fuzzy sets with a membership function, which has a trapezoidal shape, have been formed. The results of modeling a fuzzy- logic control system showed that if there is a noisy external disturbing signal in the system and its level changes up to 30%, as well as changes in the parameters of the control object (gain and constant time) up to 25% (in the direction of increasing and decreasing), the fuzzy system retains the properties of stability. Keywords Algorithm, synthesis, fuzzy controller, chemical reactor, uncertainty, linguistic variable, control system 1. Introduction Analysis of the state of the problem of designing control systems for complex technological objects shows that traditional methods of constructing models of objects and control systems for them do not lead to satisfactory results when the initial description of the problem to be solved is obviously inaccurate and incomplete [1,2,7,9]. As a rule, these poorly structured or poorly defined objects have such properties as non-stationarity of parameters, incomplete information about objects, lack of a formal description of the control object, etc. [1,6,8,12]. From the point of view of the classical theory of automatic control (ACA), the control of objects of this class is a rather complicated, in most cases unsolvable problem. This is due to the fact that when building a traditional control system (CS), it is necessary to formally describe the control