High-speed Modes Research Articles

The braking service of the linear induction motors with a compound-equalized magnetic flux for magnetic-levitation transport

In recent years, more and more attention has been paid to the development of new promising high-speed modes of the transport, especially, magnetic and vacuum pipelines. The linear induction motors will be used as traction machines in the early stages of the development of the magnetic-levitation and vacuum transport. The linear induction motors with compound-equalized magnetic flux for lines of the force, which, in addition to traction, can create lateral stabilization forces of high-speed carriages on a magnetic suspension, will be used in a magnetic vehicle in the nearest future. The effective and safe braking issues are of particular importance for high-speed magnetic-levitation transport. To reduce the speed and stop high-speed transport carriages on a magnetic suspension, the linear traction motors can operate as eddy current principle of the brakes. The article discusses the braking modes of a linear induction motor with a compound-equalized magnetic flux for lines based on the equivalent circuit of the machine. The analytical relationships are obtained for the calculation of the braking forces.

Dynamics of front propagation in a compliant channel

Front-propagating systems provide some of the most fundamental physical examples of interfacial instability and pattern formation. However, their nonlinear dynamics are rarely addressed. Here, we present an experimental study of air displacing a viscous fluid within a collapsed, compliant channel - a model system for pulmonary airway reopening. We show that compliance induces fingering instabilities absent in the rigid channel and we present the first experimental observations of the counter-intuitive 'pushing' behaviour previously predicted numerically, for which a reduction in air pressure results in faster flow. We find that pushing modes are unstable and moreover, that the dynamics of the air-fluid front involves a host of transient finger shapes over a significant range of experimental parameters.

A 1–10-MHz Frequency-Aware CMOS Active Rectifier With Dual-Loop Adaptive Delay Compensation and >230-mW Output Power for Capacitively Powered Biomedical Implants

This article presents a novel CMOS active rectifier for the emerging modality of capacitive wireless power transfer to biomedical implants with high power budgets. For operation versatility in terms of the input frequency, output power level, input voltage range, and load value, dual-loop adaptive delay compensation is utilized to provide both high resolution and high dynamic range in switched-offset currents of comparators that can be reconfigured for low- and high-speed operation modes for automatic adaptation to the input frequency. Fabricated in 0.18 $\mu \text{m}$ 1P/6M CMOS, the rectifier features power conversion efficiency (PCE) of >84.4% (peak of 91.5%) and voltage conversion ratio (VCR) of >88.6% (peak of 95.1%) when operating in 1–10 MHz and driving a load of 300 $\Omega $ . Moreover, for a load range of 20 $\Omega $ –1 $\text{k}\Omega $ at 5 MHz, PCE of 81%–91.8% and VCR of 78.4%–95.4% are achieved, with a maximum output power of ~232 mW at 50 $\Omega $ with a PCE of 90.1%. The active rectifier is also interfaced with a series-resonant capacitive link formed with coated flexible copper plates around a 3-mm-thick layer of muscle tissue, demonstrating an end-to-end power transfer efficiency of >40% in 2–10 MHz and with a load of 300 $\Omega $ .

Dispersion simulation of odorous compounds from waste collection vehicles: Mobile point source simulation with ModOdor

Odour pollution from municipal solid waste is a public nuisance and a threat to the health of residents nearby. Attention and understanding towards odour emissions from waste collection vehicles are insufficient, and dispersion simulation using conventional modelling tools cannot be applied because their special operational characteristics do not conform to either point or linear sources. This study proposes a new dispersion simulation method for mobile point sources with ModOdor, which is a 3D numerical model previously developed by the authors. The 12-month monitoring data show that ethanol, dimethyl disulphide and methylene chloride were identified as typical odorous compounds released from waste collection vehicles. Ethanol dispersion was simulated as a mobile point source for low- and high-speed modes by synchronously changing temporal and spatial grids in high precision. Results revealed the variations in concentration distribution, dispersion distance and impact duration. In general, a diameter of area with odour activity value higher than 0.1 was identified at approximately 30–50 m after stable dispersion. The impact duration varied from approximately 20 s to 40 s along with the tested source intensities, wind directions and speeds with a benchmark of 10 μg·m−3. This study verified the applicability of the proposed method for the dispersion simulation of mobile point sources and provided useful approach and information for evaluating the odour pollution from waste collection vehicles.

Analysis of acoustic signals in increments for functional diagnostics of multi-drive units

The current trend in the development of mechatronic systems is the use of multi-drive frame configurations. Such objects, as a rule, consist of a large number of interacting elements. The relative displacements of these elements generate vibrations that can critically affect the operation of precision mechatronic systems. This can lead to limiting operating conditions of the equipment, and in some cases, its failure. An effective means of preventing accidents, identifying critical modes of operation, diagnosing faults in equipment of electromechanical systems are the methods of functional diagnostics.Methods of functional diagnostics in real time require a large number of calculations, mathematical modeling of the object, processing a large amount of information, which leads to the mandatory use of computer technology. The main methods of processing the measurement results are the Fourier and Laplace transforms, classical methods for analyzing time series, multiple-scale wavelet analysis, etc. The disadvantage of the approaches used is computational complexity in the implementation of discrete transformations and the need for significant amounts of memory to store reference values. The considered methods are based on the analysis of the original signal, however, the increments of the signal of different orders may also be informative.The aim of the research is to develop methods for analyzing acoustic signals generated by working equipment of electromechanical complexes, in increments suitable for use in functional diagnostics systems when monitoring the operating modes of electric drives.In the process of research, an analysis of acoustic noise signals from a working multi-drive unit, obtained as a result of a series of experiments at two high-speed modes, was performed. To speed up the process of analyzing signals and eliminate their redundancy, a data aggregation method has been applied. The degree of permissible aggregation is determined using a multi-scale analysis. The developed method for analyzing aggregated acoustic signals in increments in phase space can be used for functional diagnostics of multi-drive units.

Enhancement of fuel consumption regulation for city buses in the Russian Federation

The stages of the development of fuel consumption regulation for vehicles in the USSR and in the Russian Federation are shown, and the main concepts of the research into fuel consumption regulation for buses are described. The paper considers mathematical models to predict fuel consumption for vehicles with regard to high-speed movement modes, and determines fuel consumption for city buses.

Performance comparison between 802.11 and 802.11p for high speed vehicle in VANET

<span>Vehicular ad-hoc networks (VANETs) technology has been emerged as a critical research area. Being ad-hoc in nature, VANET is a type of networks that is created from the concept of establishing a network of cars for a specific need or situation. Communication via routing packets over the high-speed vehicles is a challenging task. Vehicles mobility, speed can vary depending on the road specification. However, on highway, the speed can be increase up to 120 – 200 Km/H. Moving at high speed can affect the efficiency of data delivery. In particular V2I traffic where moving car trying to deliver data to fixed space units which are designed to collect and process data from vehicles. Different protocols have been proposed to be implemented for VANET infrastructure, including 802.11 and 802.11p. In this paper, the performance of the most widely deployed MAC protocols for handling wireless communication which is 802.11 and the 802.11p have been compared, which is a customized version for high speed modes. Performance is investigated in term of data delivery evaluation metrics including network throughput, delay and packet delivery ration. Results show that 802.11p has efficiently enhanced the network performance where network throughput is increased, delay is decreased, and packet delivery ratio is increased as well.</span>

Analysis of interrelation between level of mobility and transport expenses of population

Passenger transport is a basis in the transport system of any country. The task of transport is to provide an opportunity for every person to reach any point of our planet, not only safely, comfortably and quickly, but with little expenses.
 Aim: the arm of this study is to evaluate dynamics and share of transport expenses in population of the Russian Federation, and to study interrelation between figure of transport expenses of population and its transport mobility, and passenger transport fares.
 Methods: to achieve the set aim, such common scientific methods as observation, analysis, generalization, and analogy were used.
 Results: it is noted that transport expenses of the population increase at a slower pace than consumer spending. When considering the factors affecting the transportation costs of the population, it was determined that against the background of decreasing volumes of passenger traffic there is an increase in transportation tariffs. When comparing the indices of passenger tariffs and the consumer price index, a rapid increase in the cost of passenger traffic compared to prices for consumer goods was noted, which makes transport services less accessible to the public.
 Conclusion: The accelerating pace of life and economic realities today pose to transport companies certain tasks to ensure high speeds. High-speed ground transportation is coming to the fore, one of the types of which is a magnetic-vehicle transport, which, in addition to high speed, has certain advantages, such as safety, comfort, energy efficiency and high throughput. The development of new high-speed modes of transport, including a magnetic-casting, will ensure a high level of transport mobility and, accordingly, the country's economic development.

The classifications of subaxial cervical spine traumatic injuries. Part 1. General principles

Cervical spine and spinal cord injury is a significant medical and socio-economic problem of modern society. Ongoing urbanization, the development of high-speed modes of transport and the intensification of military conflicts lead to a progressive increase in the number of victims with this pathology. At the same time, unlike several other socially significant diseases, the category of the most employable population suffers from spinal injuries. Achievements of modern medicine to a much greater extent contribute to reducing the mortality of patients, rather than regression of neurological disorders. The usage of new diagnostic methods for neuroimaging and expensive surgical instruments, the continuous improvement of rehabilitation treatment of patients with spinal cord injury determine the progressively increasing costs for medical and social life support expenses. A large number of experimental and clinical studies, improvement of methods for surgical correction and stabilization of the damaged vertebral motor segment undoubtedly dictate certain changes in the tactics of treatment. The classification of traumatic spinal injuries is of key importance in determining the approaches, timing and volume of surgical intervention. Following the care algorithms helps to minimize the negative effects of traumatic damage to both the spine and the spinal cord and contributes to the maximum possible recovery of neurological functions. The last few decades have been characterized by the gradual replacement of the previously widely used “morphological” classifications of traumatic injuries of the cervical spine to “clinical” ones, based on an analysis of some heterogeneous factors determining treatment tactics. The first part of the review deals with a detailed description of the main criteria used in developing modern “clinical” classifications of subaxial cervical spine traumatic injuries. Besides, modern views on imaging methods and algorithms for determining the need to perform diagnostic procedures at primary hospitalization in patients with suspected cervical spine traumatic injury are presented.

ЗАБЕЗПЕЧЕННЯ СТІЙКОСТІ МЕХАТРОННОГО ГІДРОПРИВОДУ

In mobile and technological machines, the use of mechanotron hydraulic drives is expanded on the basis of regulated pumps, proportional valves and controllers. In such hydraulic actuators there is the use of several regulators. They operate in conditions characterized by load variations and high-speed modes in wide ranges. In such hydraulic drives, frictional forces are applied to the working bodies and valve spools, and the working fluid and pipelines are supplemented This raises the problem of ensuring the stability of mechanotron hydraulic drives at the design stage. The scheme of the mechatronic hydraulic drive on the basis of the regulated pump is presented. Hydraulic drive also includes directional valves, throttles, hydraulic cylinder, hydromotor, pressure sensors and controller. The hydraulic actuator ensures the simultaneous operation of the hydraulic cylinder and the hydraulic motor. The speed of the hydraulic cylinder and the hydromotor are regulated in wide ranges. The controller provides a change in the speed of the hydraulic cylinder when changing the load on the hydraulic motor. Such a mode of operation of the mechanotronic actuator provides adaptation to the change of external conditions. The article presents a mathematical model of a mechanotron hydraulic drive and studies the stability of its work. The influence on the stability of the parameters characterizing conditions and operating modes of the hydraulic drive has been revealed. The stability of the mechanotron hydraulic actuator is influenced by the moment of inertia on the hydromotor shaft, the mass of the working mechanism, the flow of the working fluid, the effort on the hydraulic cylinder, the moment on the hydraulic motor. It is also determined the influence on the stability of the hydraulic drive parameters of the regulators included in its composition. Increase the stability of the hydraulic drive is possible due to the choice of throttle regulator pump, the coefficient of amplification of the valve spool of the pump, the gain of the valve, damping the valve, the values of the diameter of the valve.

Improving performance: recent progress on vibration-driven locomotion systems

Improving locomotion performance is the primary objective in studying vibration-driven locomotion systems. In this paper, we report out recent progress within this topic from three aspects. First, dry friction-induced stick-slip motions, which are typical non-smooth dynamical behaviors, are analyzed and categorized based on sliding bifurcation analysis, and the sticking feature of the system is utilized to achieve directional locomotion as well as to increase average locomotion speed without additional energy input. Second, a strong global nonlinearity, bistability, is introduced into the internal oscillation, with which, unique benefits are obtained, including broad frequency bandwidth for high average locomotion speed and multiple locomotion modes. Third, by incorporating two internal oscillators into the system, planar locomotion capability is acquired; various trajectories can be executed by simply tuning the frequencies of the two internal oscillators. In addition to theoretical and numerical efforts, based on our designed prototypes, the proposed strategies and the achieved performance boosts are experimentally verified. We believe that this progress report, along with the discussions on challenging issues and directions worth exploring, could serve as a solid foundation and useful guideline of future research.

Dual-mode phase-shifting interferometry based on iterative algorithms

Iterative algorithms are useful for retrieving wavefront phase from vibration disturbed interferograms for phase-shifting interferometry (PSI). But the dependence of convergence on the initial value deviation from the exact value impairs their application in severe vibration. In this paper, performance investigation of a representative iterative algorithm indicates that a higher frame rate of the camera, with matched phase shift, helps in enhancing the success probability of convergence. However, the camera frame rate is limited by its transmission speed and could not be increased easily. To improve the convergence of iterative algorithms, a dual-mode (DM) PSI is proposed that utilises the binning function of cameras. In DMPSI, two modes, high-speed and high-resolution modes, work consecutively by switching the camera binning function and two series of interferograms are collected respectively. The wavefront phase could be accurately estimated from high-speed interferograms and then is input to the iterative calculation with high-resolution interferograms as the initial value, and a wavefront phase with high-resolution is achieved ultimately. DMPSI combines the advantages of two complementary modes of cameras to reconstruct an accurate and high-resolution wavefront. Both simulations and a practical measurement verify the enhancement of vibration resistance of iterative algorithms. DMPSI is easy to implement with low cost and good compatibility, predicating a reliable solution for optical wavefront measurement in the severe vibration.

Vibration analysis of rotating beam with variable cross section using Riccati transfer matrix method

In this paper, a semi-analytical method will be discussed for free vibration analysis of rotating beams with variable cross sectional area. For this purpose, the rotating beam is discretized through applying the transfer matrix method and assumed the axial force is constant for each element. Then, the transfer matrix is derived based on Euler-Bernoulli\'s beam differential equation and applying boundary conditions. In the following, the frequencies of the rotating beam with constant and variable cross sections are determined using the transfer matrix method in several case studies. In order to eliminate numerical difficulties in the transfer matrix method, the Riccati transfer matrix is employed for high rotation speed and high modes. The results are compared with the results of the finite elements method and Rayleigh-Ritz method which show good agreement in spite of low computational cost.

IMPROVEMENT OF THE RUSSIAN CITIES’ TRANSPORT INFRASTRUCTURE

Introduction.The problems of congestion, ecology, and road safety in most of Russia’s major cities have been accumulated in the paper. Strategic planning documents aimed at updating the gene plan, improving the transport and route network, improving traffic safety, improving environmental performance and accessibility for people with disabilities are sent for such important problems solution. The paper presents the results of the scientific research conducted in large cities of Russia. Moreover, the review of the literature is presented, and the achievements of foreign science are taken into account.Materials and methods. Modern approaches to improving the system of public transport are given, the efficiency of high-speed transport modes, the organization of transport services for the disabled and low-mobility groups, traffic safety, ecology, and the implementation of the “Transport Strategy of the Russian Federation until 2030” are approved. As a criterion for the efficiency of improving the transport infrastructure, the level of its loading by various modes of transport is used.Results.The problems of influence of the city form on the formation of the transport frame, of the density of settlement and of the efficiency of urban development are considered. New methods of predicting the transport demand of the population, the level of the transport systems’ development and assessing accessibility are proposed. Therefore, the developed algorithms and recommendations for reducing the volume of transport infrastructure helps to improve its performance and availability. Such effect is achieved through the redistribution of transport and passenger flows between different modes of transport.Discussion and conclusion.The authors comes to the conclusion that it is necessary to improve the regulatory and methodological base of the transport industry constantly, improving the performance of the transport infrastructure of modern cities.

About the Need of Carrying out Researches of Wear Resistance of Groups of Mating Parts (Shaft and Plug, Screw and Nut, Interacting Surfaces) According to the Types of Processing Equipment, Sizes, Accuracy, Types of Materials at the Different High-Speed Modes

На основе анализа факторов, оказывающих влияние на долговечность работы технологического оборудования промышленных предприятий, показана роль научно обоснованной системы планирования как функции управления техническим обслуживанием и ремонтом оборудования. Показано, что применение системы планово-предупредительного ремонта позволяет подготовить управляемую и прогнозируемую на длительный период ремонтную программу по видам ремонтов, типам оборудования, цехам и предприятию в целом; прогнозировать материальные, финансовые и трудовые ресурсы, необходимые капитальные вложения в развитие производственной базы ремонтной службы; осуществить предварительную подготовку ремонтных работ, выполнять их в минимальные сроки; повышает качество ремонта и, в конечном итоге, увеличивает надежность работы оборудования. Однако существующий уровень планирования технического обслуживания и ремонта оборудования не всегда отвечает стоящим задачам, поскольку используются устаревшие нормы и нормативы, разработанные еще в период командно-административной системы, не учитывающие технологические, материальные, временные, трудовые ограничения и зачастую устанавливаемые на основе достигнутого в отчетном периоде уровня и сложившейся динамики. Применение цифровых технологий предприятиями традиционного уклада, использующими современные технологии в качестве своей инфраструктуры, открывает возможности устранения несовершенства существующей информационной базы планирования и производства ремонтных работ и услуг на предприятии. Для этого необходимо провести исследования износостойкости групп сопрягаемых деталей (вал - втулка, винт - гайка, трущиеся плоскости) по типам технологического оборудования, размерам, точности обработки, видам материалов при различных скоростных режимах. Задача архисложная, но решение проблемы позволит реализовать упреждающее планирование и осуществление ремонтных воздействий с целью предупреждения аварийных ситуаций.

Research of high-speed operation modes of a tractor diesel on alcohol-fuel emulsions

The necessity of using alcohol-fuel emulsions as ecological energy carriers for tractor diesel engines is proved in the work. At the same time, such renewable environmental energy sources as methyl and ethyl alcohols were investigated. With the aim of developing, determining and optimizing the composition of the alcohol-fuel emulsion for tractor diesel engine 4F 11,0/12,5 conducted its tests when working on diesel fuel, methanol - and ethanol-fuel emulsions. Experimental studies have established that for use in a 4F 11,0/12,5 tractor diesel engine environmental energy based on mixtures with alcohols were used emulsions of the following composition: alcohol (methanol CH3OH or ethanol C2H5OH) is 25 %, detergent-dispersant additive succinimide C-5A - 0,5 %, water - 7 %, diesel fuel - 67,5 %. The results of experimental studies of power and economic parameters, indicators of toxicity and smoke content of the exhaust gases of the diesel operating on the ecological mixture of the above composition are presented. The transformation of the investigated diesel from petroleum diesel fuel to environmental energy allowed while maintaining the power factors to reduce the content in the exhaust gases when working on methanol-fuel emulsion - carbon black by 6,9 times, nitrogen oxides by 41,3 %, carbon dioxide by 6,7 %, carbon monoxide by 45,0 %; when operating on ethanol-fuel emulsion - carbon black by 5,2 times, nitrogen oxides by 50,2 %, carbon dioxide by 23,8 %, carbon monoxide by 25,0 %. The conclusion is made about the prospects of using such ecological energy carriers as ethyl and methyl alcohols in tractor diesel engines.

Influence of geometric parameters of the rotary hook on interaction of its elements in high-speed modes sewing machine

PurposeThe purpose of this paper is to develop the analytical model of the rotary hook geometric parameters’ interconnections, which allows determining the characteristic modes of interaction of its elements. In this study, the interaction mechanism of the bobbin case, the rotary hook and the support finger was defined, which allows to reduce the unit vibro-impact activity.Design/methodology/approachAs practice shows, the bobbin case sometimes turns against the rotary hook movement. This phenomenon can be used for the free passage of the needle thread. The change in the geometric parameters of the rotary assemble will allow to decrease its vibro-impact activity.FindingsThe interrelations of rotary assemble geometric parameters are established, and it is possible to determine the characteristic modes of its elements interaction and to establish a mechanism for controlling them. This allows reducing the vibro-impact activity of joint, improving friction modes and sewing technology. Criteria and values of a gap formation between the right contacting face of bobbin case and support finger protuberance are found.Research limitations/implicationsIn the future, it is necessary to conduct research on the behavior of the rotary assemble elements in the frequency operating modes of the sewing machine. It is necessary to show the influence of the resonance modes of operation of the rotary hook drive on the interaction of elements.Practical implicationsThe practical use of the results of the work makes it possible to reduce the vibratory impact of the shuttle, and also to create conditions for the smooth operation of the rotary hook and the bobbin case, and ensure the formation of a gap between the contacting face of bobbin case and support finger protuberance for the free passage of the needle thread. The results of the work can be used in the design of a rotary assemble with specified characteristic parameters and modes of elements interaction.Originality/valueAn analytical model of interrelations of geometric parameters of a rotating hook is developed. The characteristic modes of interaction of the rotary assemble elements were studied. The reasons for the vibro-impact activity of the rotary hook are studied. Also, the conditions under which the bobbin case will move against the direction of rotary hook rotation are determined.

Experimental Verification of a Magnetic Levitation Transport System for the OLED Display Evaporation Process Under Vacuum

The manufacturing process of OLED displays requires a high accuracy and a highly clean transport system because during the evaporation process, organic materials are inherently sensitive to contamination and uniform deposition of an organic layer is important. Roller-based transfer systems are not suitable for OLED evaporation processes because the roller-based system has a poor driving performance due to nonlinear factors such as friction and generates a large amount of dust. On the other hand, the magnetic levitation transport system has the advantage of not generating any dust, and it is possible to achieve high-precision control. In this letter, a magnetic levitation transport system for the OLED evaporation process is introduced. In particular, experimental verification of the developed system under vacuum is addressed. In terms of levitation control performance, the maximum fluctuation of the levitation airgap at a standstill is 15.3 $\mu$ m $_{pp}$ , and in low-speed and high-speed operation modes, it is 95.0 and 282.3 $\mu$ m $_{pp}$ , respectively. In terms of propulsion control performance, the maximum position error based on ISO-230-22006 standard is 1.5 $\mu$ m, and the maximum speed error at constant speed of 30 mm/s is 0.43 $\%$ . To achieve such a highly precise control, especially under vacuum, novel control algorithms such as intelligent section control are applied to minimize abrupt changes in the activation of electromagnets as the carrier moves, and command shaping algorithms are applied to prevent excitation of the resonance mode of the system while at a higher control bandwidth. Moreover, to verify long-term reliability, a 12-hour continuous operation test is conducted.

Driven Camshaft Power Mechanism of the Vehicle Diesel Engine Fuel Pump

The article deals with the actual problem associated with poor-quality operation of vehicle engines with incomplete loading and operation at partial high-speed modes. It is shown that such engine operating modes make up the bulk of the time, especially when the vehicle operates in urban conditions. Poor engine performance in these modes results in decline in fuel economy and environmental performance. To improve the technical performance of diesel engines, a device is proposed that allows control the uneven rotation of camshaft of vehicle diesel fuel pump. The kinematic schemes of the angular velocity transducers for fuel pump camshaft power mechanism, the kinematic and power drive calculation method are developed.

Development of high-speed rolling modes of trim rails in the continuous reverse train

One of the main characteristics that makes it possible to use effectively a rolling mill is high-speed rolling mode. This paper presents the results of theoretical and practical investigations of tram rails rolling technology on the modern universal rail-and-structural steel mill of EVRAZ ZSMK. A new scheme for rolling tram rails in the finishing continuous reverse train was developed. The diagrams of the rolls revolution speed in the stand with the condition of the most effective use of technical characteristics of the main drives are developed. A new approach is offered for high-speed rolling modes at the stages of piece capture, steady-state process and rolled piece release during rolling in the continuous universal train including three stands. Based on the existing equipment of the rolling mill the recommendations are given concerning the frequency of rolls revolution separately for each pass and for each stand during continuous rolling in the finishing train. A rolling method is proposed in which the capture of the tolled metal in all passes is carried out at a constant speed of rolls revolution.