Traction Problem Research Articles

Increasing the Fuel Efficiency of a Mainline Diesel Locomotive with Separate Section Loading

Purpose. The paper aims to investigate the increase of fuel efficiency of a mainline freight locomotive in the case of separate loading of diesel generators of its individual sections. Methodology. The study was carried out for the non-electrified section between Kharkiv-Sorting and Sumy stations during the movement of a freight train with 45 loaded and empty freight cars in both directions. The movement of a train with a freight mainline two-section diesel locomotive 2TE116 was taken. To determine the parameters of the movement, a mathematical model was developed, which was used to solve a series of traction problems. The traction problems are calculated for the cases of train movement with a series diesel locomotive and a diesel locomotive with separate loading of diesel generators of its individual sections. A method of loading sections is proposed for modeling and the traction characteristics of the locomotive are constructed in accordance with this method. Findings. It has been established that the use of separate loading of diesel generators of individual sections of a diesel locomotive when running a train with loaded cars reduces fuel consumption by 18.7...19.6 % compared to running a serial diesel locomotive. For the case of a train with empty cars, the reduction in fuel consumption is 8.1...10.3 % compared to a train with a serial diesel locomotive. It has been found that the movement of a train with empty cars can be carried out with traction by one section of a diesel locomotive. In this case, the reduction in fuel consumption is 29.5...31.0 %. In all the studied cases, the duration of the movement is practically the same. Originality. The authors of this paper have solved traction problems for a real track section when a train with a freight diesel locomotive is moving, where separate loading of diesel generators of its sections is used. A method for forming the traction characteristics of a locomotive with separate loading of diesel generators is proposed. Practical value. The developed mathematical models of train movement, including for the case of separate loading of diesel generators of diesel locomotive sections, can be used in the modernization of diesel locomotives or the creation of diesel rolling stock using a multi-diesel power plant.

The Role of Specialized Instruments for Advanced Endoscopic Resections in Gastrointestinal Disease.

Advanced endoscopic therapy techniques have been developed and have created alternative treatment options to surgical therapy for several gastrointestinal diseases. This work will focus on new endoscopic tools for special indications of advanced endoscopic resections (ER), especially endoscopic submucosal dissection (ESD), which were developed in our institution. This paper aims to analyze these specialized instruments and identify their status. Initially, the technical process of ESD was analyzed, and the following limitations of the different endoscopic steps and the necessary manipulations were determined: the problem of traction-countertraction, the grasping force needed to pull on tissue, the instrument tip maneuverability, the limited angulation/triangulation, and the mobility of the scope and instruments. Five instruments developed by our team were used: the Endo-dissector, additional working channel system, external independent next-to-the-scope grasper, 3D overtube working station, and over-the-scope grasper. The instruments were used and applied according to their special functions in dry lab, experimental in vivo, and clinical conditions by the members of our team. The Endo-dissector has a two-fold function: (1) grasping submucosal tissue with enough precision and strength to pull it off the surrounding mucosa and muscle, avoiding damage during energy application and (2) effectively dividing tissue using monopolar energy. The AWC system quickly fulfills the lack of a second working channel as needed to complete the endoscopic task on demand. The EINTS grasper can deliver a serious grasping force, which may be necessary for a traction-countertraction situation during endoscopic resection for lifting a larger specimen. The 3D overtube multifunctional platform provides surgical-like work with bimanual-operated instruments at the tip of the scope, which allows for a coordinated approach during lesion treatment. The OTSG is a grasping tool with very special features for cleaning cavities with debris. The research and development of instruments with special features can solve unmet needs in advanced endoscopic procedures. The latter may help to increase indications for the endoscopic resections of gut lesions in the future.

The performance of top-of-rail products under water contamination

Top-of-rail products are commonly used for friction modification in wheel-rail contact. However, the effect of environmental conditions and contaminants on their performance remains unclear. In this study, three commercial top-of-rail products were contaminated by different amounts of water. The laboratory tribometer in ball-on-disc configuration was used to measure the coefficient of adhesion in contaminated contact. The results show that water influenced tested top-of-rail products significantly. A very low coefficient of adhesion occurred in tests with oil-based top-of-rail products suggesting that water could cause traction problems on the actual railway where friction modification is being used. Water-based top-of-rail products showed more resistance to water contamination.

Study of the Aerodynamic Performance of Pantograph Bowhead with Serrated Lower Surface in the Thermal Management Systems of the High-Speed Train Electrical Devices

The thermal management problems of traction drive systems for high-speed trains are of great importance for the operation reliability of high-speed trains. The thermal performance of transformer and traction rectifier are mainly affected by the aerodynamic performance of pantograph. Nine bowheads with different sawtooth structures on the lower surface are proposed and a CFD numerical model is built with Transition SST turbulence model. The influence of the number and height of sawteeth on the aerodynamic characteristics of the bowhead flow field are investigated. The results show that compared with the rectangular bowhead, the aerodynamic drag of the 5w3h-shaped bowhead is reduced by 8.6%, 8.7%, and 9.9% at train speeds of 250 km/h, 300 km/h, and 350 km/h, respectively. The promotion of aerodynamic performance of pantograph is beneficial to improve the thermal characteristics of traction drive systems for high-speed trains.

Pressure live loads and the variational derivation of linear elasticity

The rigorous derivation of linear elasticity from finite elasticity by means of $\Gamma$-convergence is a well-known result, which has been extended to different models also beyond the elastic regime. However, in these results the applied forces are usually assumed to be dead loads, that is, their density in the reference configuration is independent of the actual deformation. In this paper we begin a study of the variational derivation of linear elasticity in the presence of live loads. We consider a pure traction problem for a nonlinearly elastic body subject to a pressure live load and we compute its linearization for small pressure by $\Gamma$-convergence. We allow for a weakly coercive elastic energy density and we prove strong convergence of minimizers.

Asymptotic Behavior of Constrained Local Minimizers in Finite Elasticity

We provide an approximation result for the pure traction problem of linearized elasticity in terms of local minimizers of finite elasticity, under the constraint of vanishing average curl for admissible deformation maps. When suitable rotations are included in the constraint, the limit is shown to be the linear elastic equilibrium associated to rotated loads.

Untying cable by combining 3D deep neural network with deep reinforcement learning

In this study, we propose a framework to solve the cable traction problem where many cables are needed, such as in factories, schools, etc. Our framework is divided into three stages: First, we use SegNet to recognize the cable in the image, build a 3D voxel model by 3D-VAE-GAN, and transform the voxel model to a 3D particle model in Unity3D by the Position-Based Dynamics method. Second, features learned by a 3D deep neural network (PointNet++) from the 3D model are fed into a deep reinforcement learning (RL) network (DQN) to get a series of actions to untie the 3D cable model in Unity3D. Finally, we input the action sequence to the robot arm to untie the cable in the real world. Experimental results show that compared with traditional methods, our method has successfully applied artificial intelligence algorithms to help the computer learn how to untie knotted cables by itself in the virtual world. The untying operations learned in the virtual world can be also used to untie the cable in the real world.

On the traction problem for steady elastic oscillations equations: the double layer potential ansatz

The three-dimensional traction problem for steady elastic oscillations equations is studied. Representability of its solution by means of a double layer potential is considered instead of the more usual simple layer potential.

Justification of the Structure of the Electric Traction Drive of the Electric Locomotive for Railway Quarry Transport

Purpose. The study is aimed at substantiating the structure and determining the main parameters of the traction electric drive of an electric locomotive for railway quarry transport, taking into account its modes of operation. Methodology. The research was carried out by means of mathematical modeling, which included solving the traction problem and evaluating the parameters of the energy exchange processes between the components of the traction electric drive. The simulation was carried out for the movement of the train along the track section and during shunting, which differ significantly in their mathematical description. During simulation of movement along the track section, the traction problem was solved using recommendations for traction calculations for train operation. A simplified model was developed to simulate movements during shunting. Determination of the parameters of the traction electric drive components is carried out by analyzing the processes of energy exchange in the traction electric drive based on the power balance. During the studies, it was assumed that the on-board energy storage in the traction mode feeds the traction electric motors of the booster section. In the electrodynamic braking mode, the energy accumulator stores energy from all traction electric motors of the electric locomotive. Findings. The authors obtained time dependences of the parameters that characterize the train movement at all stages of the cycle «empty half passage – loading – loaded half passage – unloading» (on the example of an electric locomotive for PJSC «Ferrexpo Poltava Mining»). The analysis of the obtained dependencies made it possible to determine the parameters of the main components of the traction electric drive for the proposed storage operation scenario. It was established that the energy capacity of the energy storage should be 250 kWh for one movement cycle. The energy storage power is 6000 kW. Originality. The authors of this paper for the first time proposed the structure of the traction electric drive of an electric locomotive for quarry railway transport, in which the electric motors of the control electric locomotive are powered from the catenary network, and the electric motors of the booster section are powered from the energy accumulator and are included in the operation at a load that exceeds 50% of the nominal one. Practical value. The practical value lies in the developed mathematical models of movement and energy exchange processes, which can be applied to the study of traction electric drives of vehicles of various purposes.

The meshing and failure analysis of haulage wheels with the effect by shearer’s poses

The high reliability of the longwall shearer is far-reaching to the efficient operation of coal mines and the stable supply of energy. However, traction problems caused by the haulage wheel’s failure are prominent. Therefore, for exploring the damage mechanisms of the haulage wheel by the shearer’s pose and optimizing the traction structure, a meshing model between haulage wheels and pin row is established, with the non-standard center distance and the oblique angle, respectively. And the effects of the shearer’s pose of the jumping and swinging around the vertical direction on meshing performances are studied. The result indicates the radial runout of haulage wheels is the most violent when the teeth alternate meshing, and the maximum runout amplitude is 1.563 mm. With the radial runout increasing, the average peak force increases, and the stress concentration range of the tooth root expands to the pitch line position. The shearer’s swing around the vertical direction causes the axial impact force of the haulage wheel. With the swing angle increasing, the stability and safety of the haulage wheel decrease. As the velocity increases, the axial slip on the tooth surface aggravates while effective meshing width decreases when the haulage wheel is affected by oblique angle. The result provides a reference for reducing the shearer’s hauling fault.

On a pure traction problem for the nonlinear elasticity system in Sobolev spaces with variable exponents

"The paper deals with a nonlinear elasticity system with nonconstant coe cients. The existence and uniqueness of the solution of Neumann's problem is proved using Galerkin techniques and monotone operator theory, in Sobolev spaces with variable exponents."

Numerical and Experimental Analyses of Track Shoe Patterns for Vehicle on Sandy Terrain

A track is a vehicle propulsion system that consists of a continuous band of chains connected with track shoes or may be entirely made of rubber. The track system is still commonly used on various vehicles, including bulldozers, excavators, tanks, and tractors, and has recently been used in lunar expedition vehicles. A tracked vehicle is mainly designed to provide better mobility in rough, uneven, or slippery terrain. The main component of the track system is track shoes or so-called grousers. This track shoe geometry will determine the tractive performance of the vehicle. If an incorrect shape is used, the excavator will most likely slip. The previous study approached this traction problem by using the semi-empirical method. However, until now, the track geometry and traction relation are still unclear. This research focuses on the effects of track shoe geometry on tractive performance and vehicle climbing ability. The analysis was mainly conducted with a DEM (Discrete Element Method) simulation. The result from the experimental test is also confirmed using a small-scale RC prototype on simulated terrain with different slope variations. It is proven that the grouser height directly affects the climbing performance of tracked vehicles. A higher grouser height proves to be better at a higher inclination slope. However, for a low inclination angle, the flattened track was better. The traction result from the EDEM simulation also yields a similar result. However, higher usable traction means more friction is generated; therefore, the track with higher traction also takes more energy to cover the same distance.

The use of a multistage gearbox in an electric drive on quadcopters

The purpose of the work is to develop a multistage gearbox for quadcopters with an additional mass of approximately 700 g, for example: a topographic camera, a small parcel, or, as in the case under consideration, anti-radiation protection and a sensor for measuring radiation levels. We will develop such an electric drive that will ensure the preservation of maximum speed and maximum speeds of climb and descent, as well as select a new battery to preserve such characteristics as maximum range and altitude, maximum flight time and maximum hover time. The article discusses the main stages of selecting the components of an electric drive, taking into account their mass in the required thrust, to ensure the functioning of an average quadcopter upgraded for the study of a radiation-contaminated area. An example of solving the problem of insufficient traction of electric drives is considered. Comparing the use of a multistage drive with the traditional use of an engine without a gearbox on quadcopters, it is worth noting that a multistage drive is more technologically expensive, as well as has a large mass, but at the same time it provides higher useful thrust than most engines used on modern quadcopters. Also, the advantage of the developed drive is the protection of the motor board from radiation by the housing and gearbox, which increases the service life of the quadcopter in the conditions under consideration.

Motion analysis of screw drive in-pipe cleaning robot

In-pipe cleaning robots often need to carry cleaning tools, and their tails are connected with cables such as water pipes and air pipes. Especially when cleaning vertical straight pipes and curved pipes, a greater traction is required. Therefore, a new type of screw drive in-pipe cleaning robot was designed in this paper. The robot solves the problems of small traction, complex structure, and unstable motion of the in-pipe cleaning robot. The kinematics modeling was carried out on the screw drive in-pipe cleaning robot’s screw module for generating traction, and the force analysis was performed on this basis. The function model of the torque, air pressure, and traction of the screw module was established, which was verified by the simulation and experiment. The results show that the screw in-pipe cleaning robot has a large traction, stable operation, and can be well adapted to the vertical straight pipes and curved pipes.

Traction electric drive based on fuel cell batteries and on-board inertial energy storage for multi unit train

The aim of the work is to study the possibility and features of the use of inertial storage devices in the traction electric drive of multi unit train with a power plant based on fuel cells. Methodology. The principle of power flow control in traction electric drives in the modes of acceleration and braking of rolling stock is proposed. The mathematical model of the traction electric drive in the form of the combination of three components: the train, the traction unit and the battery of fuel cells is developed. It was used to study the operation of a traction electric drive when solving a test traction task for rolling stock. Results. It is established that the use of inertial energy storage reduces hydrogen consumption by at least 25 %, which increases the mileage of rolling stock between equipment by more than 30 %. Originality. The traction electric drive on the basis of fuel elements and the inertial energy storage for the multi unit train is offered. The work of the proposed traction electric drive in solving the test traction problem for rolling stock is investigated. Practical significance. A mathematical model of the traction electric drive has been developed. The test traction problem for rolling stock is solved.

Sharp conditions for the linearization of finite elasticity

We consider the topic of linearization of finite elasticity for pure traction problems. We characterize the variational limit for the approximating sequence of rescaled nonlinear elastic energies. We show that the limiting minimal value can be strictly lower than the minimal value of the standard linear elastic energy if a strict compatibility condition for external loads does not hold. The results are provided for both the compressible and the incompressible case.

Method for constructing an adaptive suboptimal stationary train traffic controller based on artificial neural networks

The article discusses the modern methodology for performing the synthesis of a suboptimal train controller for the purpose of energy saving. The existing methods of optimal traction control have a number of disadvantages, the main one of which is the lack of direct use in the control program of the data obtained during train operation. Mathematical models used to solve the op- timal problem can be used correctly only in the case of sufficient adequacy. Adequacy check is not part of the known methods of optimal control theory. To eliminate this drawback, it is proposed to use the method of optimal (suboptimal) traction calculations based on artificial neural networks. It improves the accuracy of traction calculations, which is especially important in the aspect of considering energy savings, while reducing the need for computing power. When using this method, it is possible not only to achieve results close to the classical Bellman method, but also to train or verify the network using the recorded data. The article discusses the process of creating and training an artificial neural network based on model data to solve the problem of suboptimal control. The train motion modes obtained by Bellman's method were used as reference data for training the neural network. The presented comparative results of the two methods show the applicability of artificial neural networks for solving applied problems of train traction with the possibility of continuous learning, including the use of trip data, which can be directly included in the training or testing set.

Non-Propellant Eddy Current Brake and Traction in Space Using Magnetic Pulses

The safety of on-orbit satellites is threatened by space debris with large residual angular velocity and the space debris removal is becoming more challenging than before. This paper explores the non-contact despinning and traction problem of high-speed rotating targets and proposes an eddy current brake and traction technology for space targets without any propellant consumption. The principle of the conventional eddy current brake is analyzed in this article and the concept of eddy current brake and traction without propellant is put forward for the first time. Secondly, according to the key technical requirements, a brand-new structure of a satellite generating artificial magnetic field is designed accordingly. Then the control mechanism of eddy current brake and traction without propellant is analyzed qualitatively by simplifying the model and conditions. Then, the magnetic pulse control method is proposed and analyzed quantitatively. Finally, the feasibility of the technology is verified by the numerical simulation method. According to the simulation results, the eddy current brake and traction technology based on magnetic pulses can make the angular speed of target decrease linearly without propellant during the process. This technology has huge advantages compared with conventional eddy current brake technology in terms of efficiency and reduced propellant consumption.

Asymptotic behavior of integral functionals for a two‐parameter singularly perturbed nonlinear traction problem

We consider a nonlinear traction boundary value problem for the Lamé equations in an unbounded periodically perforated domain. The edges lengths of the periodicity cell are proportional to a positive parameter δ, whereas the relative size of the holes is determined by a second positive parameter ε. Under suitable assumptions on the nonlinearity, there exists a family of solutions . We analyze the asymptotic behavior of two integral functionals associated to such a family of solutions when the perturbation parameter pair (ε, δ) is close to the degenerate value (0, 0).

Variational linearization of pure traction problems in incompressible elasticity

We consider pure traction problems, and we show that incompressible linearized elasticity can be obtained as variational limit of incompressible finite elasticity under suitable conditions on external loads.