The main task of the technical diagnostics is determination of an object state when the data is limited. Analysis of a state is usually done in operation when the data is hard to obtain. Often there is no way to make an unambiguous conclusion, so it may be necessary to use statistical methods.
State determination depends on the completeness of the information, and the more information about the object we have, the lower the risk of an error there is. In this way, searching the object information is a relevant question.
In addition to the statistical methods, a spectral analysis method is widespread in vibration analysis. It allows to give characteristics to a frequency content of a measured signal. Cepstral analysis and wavelet analysis are less common. Using of methods of the fractal analysis is recommended to improve reliability and accuracy of the state determination.
Kostyukov V.N., Boychenko S.N., Pavlenkov D.V. Assessment of possibility of using the fractal analysis for machinery diagnostics // Operational reliability of locomotive park and increase of efficiency of train haulage. - Omsk: OSTU, 2012. - pp. 143-149
One of the most important tasks in the increase of the maintenance quality is an improvement of the operating reliability for motor driven rolling stock (MDRS) when there are low maintenance expenses as well as a limited period of time for repair and maintenance.
In the current state the rolling stock is maintained by the schedule-based preventive repair. That’s the reason of the high consumption of resources, regardless of the real operating conditions of the unit in the MDRS. At the same time, the origin and development of defects lead to unscheduled repairs as well as additional expenditures.
The solution can be provided by the on-board condition monitoring system. It makes an assessment of the state of every unit and gives objective information about the expediency of a further operation in real time. The effectiveness of the system is in its continuous operation and making a diagnosis within a period, which is less than the period prior to a malfunction development to a critical (emergency) condition. This makes possible the gradual transition from the resource-demanding schedule-based preventive repair system to the condition-based maintenance.
Machinery of auxiliary circuits including the system of the auxiliary machines is the most important machines, which provide normal functioning of all electric train systems.
The necessity of this machinery real-time condition monitoring is caused by hard service conditions, in comparison with all-industrial machines. The following conditions could cause an early mechanical failure as well as unplanned repair: the contact mains voltage fluctuation, sudden temperature difference, the high humidity, and also vibration.
Tsurpal A.E. Selection of the parameters for diagnostics of electric train auxiliary circuits’ equipment // Operational reliability of locomotive park and increase of efficiency of train haulage. - Omsk: OSTU, 2012. - pp. 143-149
The fundamental causes of operational problems of potentially dangerous and critical objects are: low objectivity of the technical condition assessment and low observability of hidden degradation processes of technical state of the objects, caused by the wear and inadequate actions of the technological, servicing and repair personnel.
Those problems can be solved with the results of real-time technical condition monitoring of the objects. On the basis of the existing normative and scientific-methodical documents the goals and objectives of monitoring are formulated and their solutions are pointed out in the article.
The complex real time condition monitoring system is also presented there.
Kostyukov V.N., Naumenko A.P. Designing and operation experience of real-time monitoring systems // The Ninth International Conference on Condition Monitoring and Machinery Failure Prevention Technologies (CM-2012/MFPT-2012)
The diagnostics of the electropneumatic system realizes the principle of unit-by-unit diagnostics with the maximal involving of regular equipment of the electric unit: compressors, control transformer, control circuit devices and manual control parts which provide autonomy from outer air-supplying sources and high automation of diagnostics process.
In the process of the electropneumatic system diagnostics of electric train section the COMPACS®-EXPRESS-TR3 system carries out an automatic control of the testing process, including: the power and control of electric circuits and pneumatic system of electric train section; management of gasdynamic processes in a pneumatic brake network, imitating different modes of equipment operation; passing the control signals into the power and auxiliary electric circuits.
The system determines quantitative characteristics of the physical values used as informative diagnostic signs: tension, current, pure resistance, pressure, time intervals, amount and duration of the impulses repetition and displays them in the monitor in a special panel. An embedded automatic expert system, in accordance with the programmed rules, issues goal indicating prescriptions on the screen to the personnel on the further actions in the form of text (expert) messages and presents the diagnostic signs on the basis of the icons colored according to the equipment state danger level.
Kostyukov A.V., Shchelkanov A.V., Kazarin D.V. Methods of EMU-train electropneumatic systems diagnostics // Operational reliability of locomotive park and increase of efficiency of train haulage. - Omsk: OSTU, 2012. - pp. 121-125
To attribute an object to one of the state types it is necessary to know the boarders of the states’ differences, also, it is reasonable to use deviations of diagnostic signs from the etalons to establish the differences.
Depending on the deviation value of diagnostic signs vector, determines the deviation of its components, traditionally differs the following main types of states: NORMAL, ACTIONS REQUIRED, UNACCEPTABLE. With the disposal of large sizes of experimental data obtained on real units with various technical conditions, the statistical analysis methods may be used for determining the borders.
For the normalization of diagnostic signs by experimental data a method described in the article has been developed and tested.
The examples of determining the borders of state differences presented in the article agree well with the data of technical standards and prove an attainable, thanks to the available metrological characteristics and implement methods of diagnosis, high discriminating ability and reliability of the faults detection at the electric equipment of various groups, particularly at the electrical control circuits, power and auxiliary circuits.
The border differences of states determined by the presented method, have a small diagnostic error, which does not exceed 3% for the 1st –class error, and 2% for the 2nd-class error with a confidence level of 0.95, which can be confirmed by the operation results of the COMPACS®-EXPRESS-TP3. The results are actively used in the technological cycles of maintenance and repair of suburban rolling stock depot in a number of multiple units of "Russian Railways, JSC".
Kostyukov V.N., Kostyukov A.V., Kazarin D.V. Method of regulation for diagnostic signs of EMU-train electric circuits // Operational reliability of locomotive park and increase of efficiency of train haulage. - Omsk: OSTU, 2012. - pp. 110-116
The bearing assemblies of the rolling stock are important parts whose condition is directly influencing reliability and safety of train operation.
One of the main requirements to the wheel-motor units is provision of the set operational resource. The bearing assemblies are crucial elements which limit the resource in general and depend on the vibration condition, manufacturing quality, repair and assembly.
Taking into account an increasing intensity of the motion and worn-out state of depots it is necessary to use all types of static and dynamic monitoring of bearing assemblies state at the train’s WMU.
For an adequate assessment of the bearing assemblies state one need to know the influence of various factors on the vibration level.
The work is aimed at finding the dependence of vibration parameters of rolling bearings on the size of defect and frequency of shaft rotation, for their diagnosing.
Kostyukov V.N., Zaytsev A.V., Basakin V.V. A research on rolling stock bearing assemblies vibration in case of rotation frequency change // Operational reliability of locomotive park and increase of efficiency of train haulage. - Omsk: OSTU, 2012. - pp. 92-97
The adopted system of maintenance and repair, relied on the resources of skilled labour force and a substantial reserve of equipment reliability for a long time, in the late twentieth century became ineffective. Numerous manual controls and diagnostics devices, existing in the technological arsenal of depot, due to low reliability of the obtained results, due to the implementation of ineffective ways of control by elements, low automation of the process of diagnosis, did not provide a way of equipment condition monitoring in the necessary volume and quality. As a result, the intensity of faults and failures of rolling stock has increased dramatically.
To change the situation revolutionary became possible only by using the automatic diagnostic systems for different types of rolling stock equipment.
The DYNAMICS SPC accumulated experience in condition monitoring and diagnostics of hazardous production facilities of various industry and transport branches has allowed to make a list of requirements and create the unique software-hardware complex – the COMPACS®-EXPRESS-TR3.
The comprehensive system for train unit diagnostics is an innovative research and designed for detailed, complex condition assessment of the main train subsystems with interactive operation at pre-repair and after-repair testing. Among the train subsystems, to be diagnosed with the system there are the control circuits, electro-pneumatic brake circuits, power circuit, heating circuit and auxiliary machinery circuits, including their electrical insulation, pneumatic system, wheel-motor units and the current collectors. As the statistics shows the subsystems’ data and the machinery included in them are most strongly influenced by the "human factor" during the repair and by external factors during operation. According to the statistics, not less than 85% of all damages and almost 80% of the cost for the maintenance and repair of rolling stock is depending on this equipment.
An effective principle of each unit diagnostics with maximum involvement of EMU-units standard equipment in the testing process is implemented and successfully approved by the system. As a consequence, it provides the autonomy and automation of the diagnostic process.
During the tests performed in the automatic emulation of various operational modes of the electric train machinery, the system determines the quantitative characteristics of the parameters and processes used as informative diagnostic features: vibration, signal spectra, voltage, current, resistance, pressure, force, time intervals, number of impulses and displays them on the monitor screen. In accordance with the programmed algorithm, a built-in automatic expert system displays purposeful instructions to the personnel for their further action in the form of text expert messages and provides a high-quality display of diagnostic signs based on the multi-colored icons, the color of which corresponds to the particular danger level of the machinery condition.
With the help of the present innovative research, for the first time for depots it became possible to:
reliably and efficiently detect failures and hidden defects of machinery, which decrease performance index and lead to the increase in power consumption of the train in general;
discover parts and machines which impair operational condition of electric machines and high-voltage switching devices;
use full resource of assemblies and machines with saving of their maintainability, consequently reducing the necessity in groundless repairs;
provide purposeful work of the maintenance staff aimed at elimination of the present defects and their root-causes;
reduce the labor intensity of the train control and set-up;
almost completely eliminate the faults in operation and unplanned repairs, due to reduction of the main cause – unsatisfactory quality of the repairs in depots.
The implementation of the innovative systems for the comprehensive condition diagnostics of the train units in such amount is carried out for the first time in Russia and surpasses the global level. It has a high economic and social impact, and is a powerful tool for increase of safety and uninterruptedness of railway transport operation. It creates prerequisites for fast reconstruction of the repair system on safe resource-saving basis.
Kostyukov V.N., Kostyukov Al.V., Kazarin D.V. Comprehensive diagnostics of EMU-trains in depot // Eurasia News (Evrazia Vesti), Sept. 2012, p.30
Due to wide application of computer technology allowing the large data arrays processing and the automation of PM planning with regard to the information received on diagnostics, maintenance, repair of equipment, data about actual failures of equipment, the new products such as CMMS (computerized maintenance management software) and EAM (Enterprise Asset Management) have come on the market. These products aim at planning the diagnostics maintenance and repair work of equipment, warehouse stock of spare parts, etc., by using the information about equipment range and configuration, periodicity of the reglamented PM, and the parameters of ambient conditions. However, the major difficulty in using these systems is the manual input of information in situation of the equipment ambient and operating conditions instability.
The actual cost of such total management substantially exceeds the calculated value and creates an illusion of efficiency. In this case, the equipment passportization, which is done by commissioning consultants and the company’s specialists, is possible; however, keeping such data base up-to-date at an enterprise that has tens of thousands units of various equipment is impossible. This is proven by the numerous articles, published in the press, and by customers’ feedback. The implementation of the PM method on such software products is possible only in small enterprises with simple configuration of process equipment. These software makes data input to the system labour-consuming and subjective that becomes the reason for the situation when more than 70% of the companies consider the results of the products’ implementation as unsuccessful, because this approach to PM does not solve their major problems: the unpredictability of equipment faults, low level of reliability of the process, and considerable losses due to shutdowns while its working condition is being restored, high maintenance and repair costs due to inefficient use of the equipment’s existing resources, high administrative costs of data input and processing.
In order to provide efficient asset management to the Customers, DYNAMICS SPC offers absolutely new unique solution Compacs Asset Management™ (САМ™), which is based on objective, relevant and timely information about the equipment condition provided by the monitoring systems COMPACS®, integrated into the single diagnostic network of the enterprise Compacs-Net®. All the above mentioned systems form the automated control system of safe resource-saving equipment operation SMSRTM™ COMPACS®.
Kostyukov V.N., Kostyukov A.V. Condition-based maintenance of machinery by ACS SMSRTM COMPACS // Industrial Automation ("Avtomatizatsiya v promishlennosty"). - 2012. - №9. - pp.12-17
The paper presents broad-scale research held by means of the COMPACS® systems of automated diagnostics and real-time condition monitoring that have been implemented on considerable amount of machinery equipment at a number of enterprises in the Russian Federation.
As a result of this research, a knowledge base of vibration parameter trends has been compiled. It reveals regularities between the type of vibration parameter measurement and the degradation of unit condition. The mathematical model of a vibration parameter trend has been confirmed experimentally, and it states an exponential growth of the vibration parameter trend at the stage of extremely gross wear.
In addition, the statistical properties of the vibration parameter trends have been researched. It has been established that generally the values of vibration parameters and their growth rates are subject to the Weibull-Gnedenko distribution.
The paper presents the developed classification of vibration parameter trends and other diagnostic features that can be measured by the Real-time condition monitoring (RTCM) systems.
Trends that have low, middle and high-speed growth rates have been discovered as well as the trends of monotonous, exponential, alternate and multimodal character. The trends that are characterized by high and low dispersion have been sorted out. Each trend type reflects different defects developing in equipment and degree of danger of these defects.
This data allowed us to calculate the norms of vibration parameters and their growth rate for centrifugal pumps and compressors. The obtained results are the base of some Russian State Standards relating to condition monitoring of equipment at hazardous industries.
Kostyukov V.N., Kostyukov A.V. Classification of vibration parameters trends for RTCM // The Eighth International Conference on Condition Monitoring and Machinery Failure Prevention Technologies (CM-2011/MFPT-2011)
Low observability of hidden destruction processes of production facilities condition caused by wear and wrong actions taken by the maintenance personnel is a fundamental reason of hazardous production facilities operational problems. The analysis of reliability of technological units of modern refinery and petrochemical complexes shows that more than ¾ of failures are machinery unit failures, high concentration of which often appears as a reason of accidents and production faults which cause unit downtime and reduce coefficients of technical use and readiness.
In order to fix this problem it is necessary to provide observability and assessment of unit condition during the manufacture and acceptance at the consumer plants, during repair in special departments of enterprises, during the assembly of units and their operation. The observability of failure development requires constant diagnostics with an automatic delivery of objective results independently from the will of executive personnel to the personnel responsible for the machinery operation. The condition diagnostic and monitoring system should reveal the failures and provide supervision for their development and timely warn the personnel about the necessity of machinery decommissioning for repair or its emergency shutdown.
The article reviews the current state standards of the Russian Federation, and the standards of the professional public organizations developed by the authors. These standards define the basic requirements for condition monitoring of the equipment at hazardous production facilities which can underlie the transition to risk monitoring of hazardous production facilities.
Kostyukov V.N., Naumenko A.P., Kostyukov An.V., Boychenko S.N., Kostyukov Al.V. Standards in the field of condition monitoring and diagnostics of hazardous production facilities // Safety of industry labor. - 2012. - № 7. - pp. 30-36