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Документ Reliability of hydropneumodrives for metal cutting equipment(Національний технічний університет "Харківський політехнічний інститут", 2023) Fatieieva, N. M.; Fatyeyev, O. M.; Poliakov, V. V.The reliability of hydropneumodrives largely determines the safety of machine tools, metal cutting equipment, the movement of transport vehicles, and the flight of modern passenger aircraft, and their failures can in some cases lead to accidents. The design stage is crucial in ensuring reliability. The main tasks of reliability research and calculation at this stage can be divided into three groups. First, it is a justification of reliability requirements for the main elements of the hydraulic pneumatic actuator (the task of reliability norming). This task is solved at an early stage of design and involves the preliminary development of the unit structure and justification of design principles. Secondly, it is to ensure the reliability of the elements and the unit as a whole. This group of tasks includes research and quantitative assessment of the efficiency of possible ways to ensure reliability; selection of basic design characteristics, statistical reserves of durability and longevity, stability reserves and other indicators; comparative analysis of options and selection of optimal designs. Thirdly, these are control calculations of the unit's reliability according to the design documentation. Algorithms for the distribution of normalised reliability indices at the design stage for hydropneumodrives implemented by the standard positional structure method and the minimisation method are obtained. Algorithms allow already at the early stages of hydropneumodrive design to normalise reliability indices, which makes it possible to obtain optimal solutions of reliability issues at the subsequent stages of development of the drive life cycle. The methods of calculation and determination of design relations for finding quantitative characteristics of failure-free indices of designed hydropneumodrives, implemented by the method of standard positional structure and the method of minimisation, are selected, which allows designing highly reliable hydropneumodrives for new metal cutting equipment. Evaluation of reliability indicators of hydropneumodrives at the stage of preliminary design allows to make a rational choice of structural scheme and parameters, to select appropriate materials and elements of scheme realisations.Документ Synthesis and analysis of control schemes of hydropneumatic drives(Національний технічний університет "Харківський політехнічний інститут", 2021) Lynnyk, Aleksandr; Cherkashenko, M. V.; Fatieieva, Nadezhda; Fatyeyev, Aleksandr; Ponomarov, VladyslavThe method of analysis of circuits of hydropneumatic actuators is offered, which allows to detect and eliminate existing design errors, mainly related to the inconsistency of inputs operating between technological operations and "power struggle" on actuators, as well as the method of synthesis to obtain the scheme, which contains close to the minimum number of logical elements. A formalized method of analysis of control circuits of hydropneumatic actuators is proposed, which allows to detect and eliminate errors possible during synthesis. Equations of output functions and internal states of the system are written directly according to the scheme of the hydropneumatic drive by the method of standard positional structure and from the matrix of correspondences by the method of minimization. Error detection is carried out by determining the correctness of the graph of operations, analysis of the input sequence, the correctness of the matrix of correspondences and the corresponding system of equations. The efficiency of using the matrix of correspondences of M. Cherkashenko for the analysis of schemes is shown, the dimension of which does not depend on the number of inputs and outputs, but only on the number of transitions between technological operations. The proposed method is an effective means of detecting errors, inaccuracies, performance checks, rational construction of circuits, and can be widely used by designers of control systems for hydropneumatic actuators, as well as university students in the study of methods of construction of circuits.