Describing a Set of Points with Elliptical Areas: Mathematical Description and Verification on Operational Tests of Technical Devices

The purpose of this article was to present an algorithm for creating an ellipse for any data set represented on a two-dimensional reference frame. The study objective was to verify the developed method on real results of experimental tests with different subject matter. This article contains a mathematical algorithm to describe a set of points with elliptical areas. In addition, four results of tests with different subject matter are cited, based on which the developed method was verified. The verification of the method included checking the deviation of the geometric dimensions of the ellipse, the number of points contained within the ellipse, and the area of the ellipse. The implemented research methodology allowed to demonstrate the possibility of using the method of describing a set of points with elliptical areas, in order to determine quantitative parameters evaluating the results of the test. The presented results show the method’s applicability for the results obtained in four different operational tests: measurement of the human body’s gravity center position for a person propelling a wheelchair, measurement of marker position using motion capture methods, measurement of particulate emissions when using equipment powered by an internal combustion engine, and measurement of the muscle activity of the upper limb when propelling a hybrid manual-electric wheelchair. The performed experiments demonstrated that the method allows to describe about 85% of all measurement points with an ellipse.

Development of an estimation-experimental method for estimating the preservation indicators of single-use articles

To manage the operation of modern single-use products, it is necessary to evaluate their preservation indicators as uncontrolled, non-repairable, and maintenance-free objects. Data for assessing its parameters are considered as one-time censored samples with continuous monitoring, which does not correspond to the mode of storage of products during operation. Under the conditions of limited volumes of censored samples, it is problematic to identify the parametric model of persistence. To solve this problem, a non-parametric estimation-experimental method has been devised, which is a set of models for data generation, estimation of the function of the distribution of the preservation period and preservation indicators. The data generation model is represented by a scheme of operational tests and analytical relationships between the quantities of tested and failed articles. The model of estimating the distribution function describes the process of its construction on the generated data. Models for estimating preservation indicators are represented by ratios for their point and interval estimates, as functionals from the restored distribution function. Unlike the well-known ones, the developed method implements the assessment of indicators under the conditions of combined censorship. The method can be used to assess the preservation indicators of single-use articles with an error of at least 7 %. At the same time, their lower confidence limits are estimated at 0.9 with an error not worse than 14 % with a censorship degree of not more than 0.23. The restored distribution function agrees well (reliability 0.9, error 0.1) with the actual persistence of articles with censorship degrees of not more than 0.73, which is acceptable for solving the problems of managing their operation.

Assessment of tribotechnical properties and resistance to wear of plasma coatings

In order to determine the operating conditions of parts for which restoration of worn surfaces is acceptable by the method of plasma spraying of various powder alloys, contact fatigue tests were carried out under cyclic contact impulse loading. In addition, tribotechnical tests were carried out with various wear-resistant coatings under conditions of liquid sliding friction. Bench and operational tests showed the use of coatings obtained using modern plasma technologies, the feasibility of protecting parts operating in conditions of corrosion, waterjet and cavitation wear, as well as in sliding friction. The coating sprayed with Ni-Al intermetallic alloy powder provides the most reliable protection against shock cyclic impact and abrasion during liquid friction than other materials studied. Coating with wear-resistant self-fluxing powder Ni-Cr-B-Si-C alloy, hardened by solid carboboride phases, without its additional heat treatment for restoration of surfaces working in sliding friction pairs, is not recommended.

PERFORMANCE CHARACTERISTICS OF PAINT AND VARNISH MATERIALS FOR MARKING ROADS BASED ON LOCAL RAW MATERIALS

The aim of this work is to develop the technology of obtaining high-performance paintwork materials for road markings on the basis of local raw materials. The existing paint and varnish materials (paintwork materials) for road markings have been studied. Samples of paint and varnish materials for use as road markings were obtained under laboratory conditions. Laboratory and operational tests were conducted to determine the main quality indicators of the paint and varnish materials. As a result of monitoring the condition of road markings for two months it was found that the alkyd-based paintwork material retains its properties (color, adhesion, abrasion resistance) during the observed period and can be recommended as a coating for road markings.

Improvement of the tribological properties of heavy-loaded friction units “Centre block-footstep bearing” of a freight car

Various problems and different approaches of solution of such a problematic unit as “centre block-footstep bearing” of freight cars are discussed in the paper. The methods of improving the tribological properties of this friction unit by means of material modification of friction surfaces and perfection of physical, chemical and tribological properties of the used lubricants were studied. Grease lubricants common for friction units of railway machinery were used after being modified with inorganic polymers based on double metaphosphates. Bench and operational tests of the developed additive of the polymeric double metaphosphates were carried out. This additive reduces wear and increases the service life of the friction unit, due to the better adhesion properties of this additive. The variants with a change in the geometry of the contact surface of the disk between the bolster and the “centre block-footstep bearing” arrangement of the car are considered. Simulation of the parameters of movement in curved sections is proposed.

Simulation modelling of operational tests to assess the reliability of railway automation software systems

A simulation model for in-servicetesting of software reliability assessment for railway automation systems is described in this paper. As a basic concept, the reliability indicators are calculated using the concept of a reference object, being the most common element of the respective train protection systems on the road network. We are aware that this concept is embedded in the subsystem for the formation of the reference object-element infrastructure of JSC “Russian Railways”, involving the function of bringing all track, electrification and power supply facilities as well as automation and telemechanics facilities to the reference objects. In order to develop this approach, the “Performance Test Simulation” application was developed on the Windows Presentation Foundation (WPF) platform, using the object- and component-oriented programming language C#, allowing the practical simulation of performance tests of reference objects of various types, during the design phase, using the Monte Carlo method.

Design of a Low-Cost Small-Size Fluxgate Sensor

Traditional fluxgate sensors used in geomagnetic field observations are large, costly, power-consuming and often limited in their use. Although the size of the micro-fluxgate sensors has been significantly reduced, their performance, including indicators such as accuracy and signal-to-noise, does not meet observational requirements. To address these problems, a new race-track type probe is designed based on a magnetic core made of a Co-based amorphous ribbon. The size of this single-component probe is only Φ10 mm × 30 mm. The signal processing circuit is also optimized. The whole size of the sensor integrated with probes and data acquisition module is Φ70 mm × 100 mm. Compared with traditional fluxgate and micro-fluxgate sensors, the designed sensor is compact and provides excellent performance equal to traditional fluxgate sensors with good linearity and RMS noise of less than 0.1 nT. From operational tests, the results are in good agreement with those from a standard fluxgate magnetometer. Being more suitable for modern dense deployment of geomagnetic observations, this small-size fluxgate sensor offers promising research applications at lower costs.

Autonomous Transport Innovation (ATI) : integration of autonomous electric vehicles into a tactical microgrid

The objective of the Autonomous Transport Innovation (ATI) technical research program is to investigate current gaps and challenges then develop solutions to integrate emerging electric transport vehicles, vehicle autonomy, vehicle-to-grid (V2G) charging and microgrid technologies with military legacy equipment. The ATI research area objectives are to: identify unique military requirements for autonomous transportation technologies; identify currently available technologies that can be adopted for military applications and validate the suitability of these technologies to close need gaps; identify research and operational tests for autonomous transport vehicles; investigate requirements for testing and demonstrating of bidirectional vehicle charging within a tactical environment; develop requirements for a sensored, living laboratory that will be used to assess the performance of autonomous innovations; and integrate open standards to promote interoperability and broad-platform compatibility. The research performed resulted in an approach to develop a sensored, living laboratory with operational testing capability to assess the safety, utility, interoperability, and resiliency of autonomous electric transport and V2G technologies in a tactical microgrid. The living laboratory will support research and assessment of emerging technologies and determine the prospect for implementation in defense transport operations and contingency base energy resilience.

Integration of autonomous electric transport vehicles into a tactical microgrid : final report

The objective of the Autonomous Transport Innovation (ATI) technical research program is to investigate current gaps and challenges and develop solutions to integrate emerging electric transport vehicles, vehicle autonomy, vehicle-to-grid (V2G) charging and microgrid technologies with military legacy equipment. The ATI research area objectives are to: identify unique military requirements for autonomous transportation technologies; identify currently available technologies that can be adopted for military applications and validate the suitability of these technologies to close need gaps; identify research and operational tests for autonomous transport vehicles; investigate requirements for testing and demonstrating of bidirectional-vehicle charging within a tactical environment; develop requirements for a sensored, living laboratory that will be used to assess the performance of autonomous innovations; and integrate open standards to promote interoperability and broad-platform compatibility. This final report summarizes the team’s research, which resulted in an approach to develop a sensored, living laboratory with operational testing capability to assess the safety, utility, interoperability, and resiliency of autonomous electric transport and V2G technologies in a tactical microgrid. The living laboratory will support research and assessment of emerging technologies and determine the prospect for implementation in defense transport operations and contingency base energy resilience.