Modern diagnostic systems are characterized by that the flow of diagnostic information requires significant computational resources to process. In order to improve the reliability of the object to be diagnosed and reduce operating costs, it is necessary to improve procedures for analyzing diagnostic results. This paper suggests a procedure to form the diagnostic features of locomotive nodes based on the use of a principal components analysis. The proposed approach is distinguished by a decrease in the dimensionality of the input set of diagnostic features in order to select the sets of interconnected diagnostic parameters. Based on the selection of the sets of interconnected diagnostic features, constructing new latent diagnostic parameters has been proposed. A latent diagnostic parameter contains information that combines data from several initial diagnostic features. The result of the method is a set of latent diagnostic parameters that do not correlate with each other and reflect the behavior of the object to be diagnosed from different technical points. The application of a sufficient number of latent diagnostic parameters involved the scree test method. This paper reports the results from using the proposed approach for treating the results from diagnosing the hydraulic transmissions in locomotives. The result from applying the procedure has made it possible to propose using three latent diagnostic parameters to assess the technical condition of a locomotive’s hydraulic transmission during bench tests. The suggested parameters contain 90 % of the original information and reflect losses in the transmission, as well as the load at the input and output of the transmission.
Purpose. The article is aimed to evaluate the influence of locomotives` operation and reliability indicators on the system of locomotives repair organization in depot, using the methods of queue theory. Methodology. The article describes the locomotive repair workshop using the terms and concepts of the queue systems theory (QST). The tasks solved during simulation of the repair workshop operation are formulated, the list of initial data and simulation results is given. A graphical simulation environment Simulink was used as a software simulation tool. Findings. It was established that the main indicators of locomotive depot operation are affected by the volume of traffic, the reliability of locomotives, the rule used to select locomotives from the queue, the number of operating repair bays. The developed model of the depot repair workshop will make possible rational planning of the repair workshop`s equipment use, the human capital, the time of putting the locomotives into repair taking into account the workshop loading uniformity, as well as to improve the repair parts supply logistics. This model in a simplified form describes the repair process of the main diesel locomotive fleet, and can be supplemented depending on the repair type performed in the depot. Originality. The paper presents the locomotive repair depot as an object of the queue systems theory. The simulation model of the locomotive repair depot was developed. It allows analyzing the influence of various factors on the system of locomotives` repair organization in the depot. Practical value. The obtained results make it possible to determine the influence of locomotives` operation and reliability indicators on the organization of the locomotive repair depot operation. In further studies, the developed model can be used to improve the system of repair organization on the railway network when introducing new series of locomotives and changing the strategy of their maintenance.Keywords: locomotive repair workshop; simulation; queue system theory; organization of the repair workshop operation ISSN 2307-3489 (Print), ІSSN 2307-6666 (Online) Наука та прогрес транспорту. Вісник Дніпропетровського національного університету залізничного транспорту, 2018, № 5 (77) ЕКСПЛУАТАЦІЯ ТА РЕМОНТ ЗАСОБІВ ТРАНСПОРТУ Fig. 2. Repair workshop model of diesel locomotives in the form of QS: 1former of the receipt time of locomotives for repair; 2block of the former of the application distribution in time; 3former of diesel locomotive service time at repair position; 4diesel locomotive repair positions; 5queue of locomotives waiting for repair ISSN 2307-3489 (Print), ІSSN 2307-6666 (Online) Наука та прогрес транспорту. Вісник Дніпропетровського національного університету залізничного транспорту, 2018, № 5 (77) ЕКСПЛУАТАЦІЯ ТА РЕМОНТ ЗАСОБІВ ТРАНСПОРТУ
The widespread introduction of information technologies in the systems that manage technical fleets, the use of maintenance and repair systems based on risk assessment, is based on the calculation of a large enough number of indicators. Modern locomotives are equipped with systems for monitoring and diagnosing technical condition. Combining these systems with the Internet of Things and Big Data technologies provides an opportunity to use completely new approaches to fleet management. At the initial stage of the construction of such systems, it is necessary to devise criteria that make it possible to automatically determine the technical condition of a locomotive and its components in order to identify the locomotive in the total fleet that requires maintenance or repair. A procedure has been proposed for calculating the technical condition index of locomotives and their components based on data from monitoring systems. The procedure is based on the formation of latent diagnostic parameters employing the principal component method and on the subsequent calculation of the weight coefficients of these parameters applying the method of hierarchy analysis. The special feature of the proposed procedure is that when calculating the index, those latent diagnostic parameters are used that are derived from the group of control parameters whose weight coefficients are computed using the method of hierarchy analysis without involving experts. This paper reports the results from calculating the informativeness of the diagnostic parameters of load, loss, input, as well as their weight coefficients. The highest information content, from 0.5 to 0.85, is demonstrated by the load parameter; the smallest (0.05‒0.26) ‒ the input parameter. The average value and the dependences of changes in the technical condition index of a hydraulic transmission during the tests have been determined. Analysis of the technical condition index makes it possible to assess the transmission's response to changes in test modes, the dynamics of changes in losses
Purpose. Improving the efficiency of the use of locomotives by choosing a rational maintenance system that takes into account the assessment of the effect of dependent failures on the cost of their life cycle is the main purpose of this paper. Methodology. The relevance of introducing LCC (Life Cycle Cost) approaches in locomotive facilities is explained by the introduction of new locomotives with on-board control and diagnostic systems, as well as the development of the theory of traction rolling stock maintenance systems. The cost of a locomotive as a traction unit ceases to be the determining factor. This is because the locomotive maintenance and repair cost for the entire period of its operation is much higher than the initial cost of the locomotive. The paper analyses the existing approaches to managing the cost of the life cycle of locomotives at the stages of selecting, updating, upgrading and operating the traction rolling stock. The necessity of improving the methods for assessing the degree of influence of reliability indicators of locomotive assemblies on the choice of the maintenance system and the cost of the locomotive life cycle is substantiated. Findings. It is proposed to use the concept of «the effect of dependent failures» when calculating the cost of locomotive renewal after unscheduled repairs and its life cycle cost. We improved the methods for determining the cost of unscheduled repairs, taking into account dependent failures and the coefficient of assessment of the effect of dependent node failure on the locomotive maintenance system. The proposed coefficient will determine the nodes, the failure of which affects the renewal cost more than their nominal value. It will also help to take into account the probable losses due to node failure during the development and adjustment of the locomotive maintenance system. Originality. For the first time, it is proposed to use the concept of the effect of dependent failures to calculate the locomotive renewal cost when performing unscheduled repairs, as well as the locomotive life cycle cost. Practical value. The improved calculation method for determining the cost of unplanned repairs with account taken of dependent failures can be used to compare and evaluate different variants of the locomotive maintenance system and to develop the locomotive diagnostic systems.
The analysis of the existing system repair rolling stock industry and proposed to use structural and functional models that allow to create effective communication system repairs.
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