Browsing by Author "Bobrovskyi, Volodymyr I."
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Item Controlling the Speed of Rolling Cuts in Conditions of Reduction of Brake Power of Car Retarders(Дніпропетровський національний університет залізничного транспорту імені академіка В. Лазаряна, Дніпропетровськ, 2016) Kozachenko, Dmytro M.; Bobrovskyi, Volodymyr I.; Grevtsov, Serhii V.; Berezovyi, Mykola I.ENG: Purpose. The study aims to develop the requirements for organization of the marshalling process in the conditions when the power of retarder positions is less than the nominal one. Methodology. The research is carried out using the train traffic safety theory and mathematical modelling of hump processes. Findings. The current technical standard documents regulating the operational performance of humps do not contain direct instructions on how to proceed in the event of brake power loss by car retarders, thus creating threats to the traffic safety. This problem is quite acute for the Ukrainian railways in connection with a chronic shortage of funds for the repair and renewal of technical equipment, including the humps. At the same time, a significant drop in the volume of work leads to the fact that the hump required processing capacity can be provided in case of partial failure of retarders as well. Herewith the most important task is to ensure the breaking-up safety in conditions of parametric failures of retarders. The analysis of dangerous situations, the occurrence of which is possible at humps, as well as the modelling of cut rolling, allowed establishing the connection between the value of retarder tire pressing force on the car wheels and the breaking-up modes, providing the safety of marshalling process. The paper sets the application areas of such measures as the breaking-up speed reduction, breaking-up termination, the use of additional braking by block hangers. Originality. The originality of the work lies in the fact that it first obtained the complex of dependencies that determine the performance requirements for the power of hump retarders and allow the staff to enter the appropriate limits for breaking-up modes to ensure the marshalling process safety. Practical value. The results of the research can be used to supplement the «Instruction on the maintenance of facilities of mechanized and automated humps» in order to determine the limits of breaking-up modes when detecting the reduction of retarder power below the nominal one.Item Functional Simulation of Railway Stations on the Basis of Finite-State Automatа(Silesian University of Technology, Poland, 2014) Bobrovskyi, Volodymyr I.; Kozachenko, Dmytro M.; Vernigora, Roman V.ENG: The general scheme of railway station’s model and technique of formalizing the technologic processes at stations are described. To take into account the human impact on station’s operation is suggested to use ergatic models. In conformity with concept of stations’ ergatic models a person is directly involved into the simulation process and manages the station technological processes acting as a dispatcher. The formalization of technological processes for processing the objects is performed on the basis of deterministic finite-state automaton. Designed model can be used for optimization of technical and technological parameters of railway stations, as well as in computer simulators for training of railway traffic managers.Item Improving the Efficiency of Multi-Group Trains Formation(Kaunas University of Technology; Publishing House "Technologija", 2019) Kozachenko, Dmytro M.; Bobrovskyi, Volodymyr I.; Skovron, Ihor Ya.; Jablonskyte, J.ENG: The formation of multi-group trains is one of the typical tasks solved in the process of operational work of railways. The purpose of this study is to reduce the time spent on shunting operations associated with the formation of multi-group trains. The studies are performed using the method of simulation modeling. The method of searching for a rational order of multi-group train formation was improved. It is based on the statistical evaluation of the variety of simulation modeling results of shunting movements, the sequence of which is determined using the various methods and formation schemes. The choice of the best method and the scheme of train formation makes it possible to reduce the duration of shunting by 7.1-23.3% when using a flat shunting neck and by 8-11% when using a sorting hump. The methods presented in this paper make it possible to develop software products for the automated preparation of shunting plans for the formation of multi-group trains at the stations.Item A Method for Optimization of Time Intervals between Rolling Cuts on Sorting Humps(Springer, Heidelberg, 2018) Kozachenko, Dmytro M.; Bobrovskyi, Volodymyr I.; Demchenko, Yevhen B.ENG: Abstract Sorting humps are the main technical means providing the breaking- and making-up of freight trains. Automation of sorting process by implementing microprocessor control systems is the main direction of increasing hump yard capacity, enhancement of safety in trains breaking-up, improvement of working conditions on hump yards. However, for wider introduction of such systems at the humps, it is necessary to reduce their cost. One of the main tasks of hump control systems is the determination of the optimal cars exit speeds from the retarders. Its solution is significantly complicated because of the uncertainty of cars rolling resistance coefficient, wind velocity and direction, retarder control errors. The paper is aimed at solving the problem of searching for such cars exit speeds from the retarders that provide the longest time intervals between them at the switches. Implementation of this method will make it possible to improve the quality of sorting process as a whole by improving the software of microprocessor control systems for automatic humping, rather than by increasing their technical facilities, which as a result will reduce the cost of their construction and operation. The research results, when solving the problem of searching for cars exit speeds from the retarders, allow us to move from searching for the maximum of a nonlinear non-smooth function of two variables to solution of an equation with one variable, which significantly accelerates and simplifies the solution to the problem.Item Probabilistic Approach for the Determination of Cuts Permissible Braking Modes on the Gravity Humps(Silesian University of Technology, Poland, 2016) Bobrovskyi, Volodymyr I.; Kozachenko, Dmytro M.; Dorosh, Andrii S.; Demchenko, Evhen B.; Bolvanovska, Tetiana V.; Kolesnyk, Anton I.ENG: The paper presents the research results of cuts braking modes on the gravity humps. The objective of this paper is developing the methods for assessment of braking modes of cuts under conditions of fuzziness of their rolling properties, as well as selecting the permissible starting speed range of cuts from retardant positions. As a criterion for assessing the modes of target control of cut rolling speed, it was proposed to use an average gap size on a classification track at the established norms of probable exceeding of permissible speed of cars collision and their stop in retarders. As a criterion for evaluating the modes of interval control of cuts rolling speed, using the risk of their nonseparation on the switches was proposed. Using the simulation modeling and mathematical statistics, the configuration of the range of permissible speed of cuts coming out from retardant positions has been set. The conducted researches allow simplifying the choice of cut braking modes in systems of automatic control of cut rolling speed.Item The Research of the Domain of Permissible Braking Modes of Cuts on the Gravity Humps(Silesian University of Technology, Katowice, 2015) Bobrovskyi, Volodymyr I.; Kozachenko, Dmitriy N.; Dorosh, Andrii S.; Demchenko, Evhen B.; Bolvanovska, Tetiana V.; Kolesnyk, Anton I.ENG: The paper presents the research results of cuts braking modes on the gravity humps. The objective of this paper is developing the methods for assessment of braking modes of cuts under conditions of fuzziness of their rolling properties, as well as select-ing the permissible starting speed range of cuts from retardant positions. As a criterion for assessing the modes of target control of cut rolling speed, it was proposed to use an aver-age gap size on a classification track at the established norms of probable exceeding of permissible speed of cars collision and their stop in retarders. As a criterion for evaluating the modes of interval control of cuts rolling speed, using the risk of their non-separation on the switches was proposed. Using the simulation modeling and mathematical statistics, the configuration of the domain of permissible speed of cuts coming out from retardant positions has been set. The conducted researches allow simplifying the choice of cut braking modes in systems of automatic control of cut rolling speed.Item Researching Operation of the Railway Stations with Using of Their Ergatic Simulation Models(Дніпропетровський національний університет залізничного транспорту імені академіка В. Лазаряна, Дніпропетровськ, 2013) Bobrovskyi, Volodymyr I.; Kozachenko, Dmytro M.; Vernigora, Roman V.ENG: The general scheme of railway station’s model and technique of formalizing the technologic processes at stations are described. Designed model can be used for optimization of technical and technological parameters of railway stations, including with using the grapho-analitical method.