Traction Calculation Research Articles

Determination of Design Solution for a 6x6 ATV with an Electromechanical Transmission

The article provides an overview and analysis of the current state of development of 6x6 ATVs and the scope of the developed ATV, as well as technical characteristics of 6x6 ATVs with a mechanical transmission. The choice and justification of design solutions for a 6x6 ATV with an electromechanical transmission are presented. Also, the selected structural and design solutions for the developed ATV are substantiated based on the selected electric drive scheme taking into account the traction calculation for the selected electric motor.

Design and Development of Simulation Computer Software for Safety Siding in Regional Expressed Railway

The safety siding is an isolated line used to ensure safety on traffic operating. Too short a safety siding does not guarantee the safe operation of the train, while too long a safety siding will increase the cost and design difficulty of construction. The prior art specification says the length of the safety siding required is not less than 50m. Obviously, there is still uncertainty about the setting length of safety siding on specific line. This paper combines the characteristics of the suburban railway to design and develop a setting simulation system of safety siding. The safety siding calculation model is established by the traction calculation method, which includes different factors such as braking ratio, train speed, line parameters, signal system and application scenarios. Moreover, it designs the structure and function of the simulation system and discusses the key techniques of simulation. Finally, taking the Fuzhou Railway Station as an example to verify the simulation system. The results show that when the different lines and train parameters are configured, the design length of the result is also different. The simulation system could accomplish the design of the safety siding in different scenes. The calculation results are reliable and have engineering application value.

Guidance and evaluation system for smooth operation of heavy-haul trains

Abstract The operation rules and methods for heavy-haul trains were studied and summarized according to the characteristics of the Daqin Railway, such as a large traffic volume, a high density and high-speed and difficult-to-operate heavy-haul trains. Combined with traction calculation and operation experience, these can be quantificationally decomposed into an evaluation standard for the smooth modularized operation of heavy-haul trains that can be recognized by computers. A train operation guidance system was designed to collect locomotive drivers’ operation data, display the actual operation and standard curves in real time and give voice prompts and violation-operation alarms for safety-critical operation. In addition, software for operation analysis and evaluation was developed according to the quantified smooth operation standard. The smooth operation of heavy-haul trains was evaluated and statistically analysed through a comparative analysis of the actual operation records. Moreover, a train impact force detection device capable of monitoring the three-dimensional impact force of heavy-haul trains in real time was developed. Meanwhile, the evaluation standard for smooth operation was verified and optimized by real-time monitoring of the impact force of heavy-haul trains. Finally, on the basis of the above studies, a complete closed-loop management scheme for the smooth operation of heavy-haul trains was constructed, and the objectives of optimizing train operation strategy, standardizing drivers’ operations and ensuring the smooth operation of trains were realized through application.

Annelida, a Robot for Removing Hydrate and Paraffin Plugs in Offshore Flexible Lines: Development and Experimental Trials

Summary Methane hydrates and paraffin plugs on flexible lines are concerns in offshore production. They may stop wells for months, causing high financial losses. Sometimes, operators use depressurization techniques for hydrate removal. Another strategy is using coiled tubing or a similar unit to perform local heating or solvent injection. However, frequently these strategies are not successful. In those cases, a rig may perform the operation, or the line may be lost. We developed a robotic system to perform controlled local heating and remove obstructions. The system developed can access the line from the production platform. It uses a self-locking system to exert high traction forces. An umbilical with neutral buoyancy and low friction coefficient allows significant friction reduction. It allows moving upward and in pipes with a large number of curves. Coiled tubing and similar units cannot do that. Carbon fiber vessels and compact circuits give the flexibility to move inside 4-in. flexible pipes. In addition, a novel theoretical model allows the cable traction calculation using an evolution of the Euler-Eytelwein equation. Experimental tests validated this model using curved pipes, both empty and filled with fluid, and using different loads. Experimental tests also confirmed the external layer traction resistance. Furthermore, the carbon fiber vessels were pressure tested, indicating a collapse resistance of 57 MPa (8,300 psi). Besides, exhaustive tests of the onboard electronics and the surface control system guarantee the communication reliability. In addition, a theoretical model allowed the design of the 25 kN (5.6 kip) traction system considering the self-locking system, the contact with the wall, and a diameter range. Four prototypes allowed us to compare hydraulic and electric drive systems, validate the self-locking mechanism up to its limit, analyze the hydraulic system for leg opening and translation, and prove the traction capacity. Finally, a theoretical model allowed the local heating system and the temperature to increase. The experimental validation of the system on a cooled environment demonstrated its ability to increase temperature. Further, it allowed the obstruction removal in a controlled manner, avoiding damage to the polymeric layer of the flexible line.

ОСОБЕННОСТИ ДЕФОРМАЦИИ ЖЕЛОБЧАТОЙ КОНВЕЙЕРНОЙ ЛЕНТЫ ПРИ МАЛЫХ НАТЯЖЕНИЯХ

The article presents analytical dependences for the maximum permissible bending radius of the conveyor belt in the longitudinal direction, in which the shape of the gutter is lost in areas with low tension, depending on the design and physical and mechanical properties of the belt. The results of calculations based on these dependencies for a number of modern rubber-fabric and rubber-rope belts are presented. The results obtained can be applied to determine the minimum allowable belt tension and the maximum allowable belt deflection, which usually occur in the loading zone of the conveyor and are the starting value when constructing a tension diagram in the process of traction calculation of the conveyor. They are also useful for determining the parameters of transition sections of conveyor belts.

Numerical analysis of the traction effect on reciprocating seals in the hydraulic actuator

Abstract Reciprocating seals guarantee the normal work of hydraulic actuators. Friction in the rod-seal contact pair acts as a tractive force, changing the seal's deformation and contact-pressure distribution. However, previous studies have not considered this traction effect. This paper proposes one numerical analysis procedure for investigating the friction's inverse influence on the sealing performance. The analysis procedure consists of three parts: dry traction analysis, basic film computational procedure and mixed-lubrication traction calculation. Characteristics of the O-ring seal, both with and without considering the traction effect, are presented and compared. Different friction coefficients, system pressures and velocities are also discussed. The results indicate that the traction produces a significant effect on seal performance and causes pronounced different influences for the outstroke and instroke.

System-Level Dynamic Energy Consumption Evaluation for High-Speed Railway

This article studied a system-level energy consumption evaluation method for high-speed railway. Three coupled subsystems, namely, the traction power supply network (TPSN), the traction drive system (TDS), and the wheel-track motion system (WTMS), were identified, and corresponding energy dissipation behaviors of subsystems were analyzed in typical scenarios. Then, the traction calculation technologies were applied to calculate the dynamic power and energy consumption in the WTMS for one train as well as for multiple trains scheduled by the train timetable in 24-h. On this basis, rated efficiency of the devices in the TDS was applied to calculate the corresponding dynamic power and energy consumption. Furthermore, dynamic modeling and power flow solution technologies were conducted to calculate the dynamic power and energy consumption of the devices in the TPSN according to the dynamic power of the TDS and the running parameters of the WTMS. Based on the dynamic power and energy consumption results in the subsystems, an energy source identification algorithm was proposed to realize the refined energy management, and a set of energy metrics was presented to evaluate the energy consumption performances. Case studies were carried out to verify the effectiveness and potential applications of the proposed method.

Influence of variable slip frequency control strategy on tractiv e performance

In order to improve the current situation of poor traction ability of medium-low speed maglev train, a variable slip frequency control (VSFC) strategy is proposed based on the constant slip frequency control (CSFC) of linear induction motor (LIM). The control frequency of the starting stage of the vehicle is selected low on the premise of no obvious influence on the levitation performance. After reaching the maximum power point, the traction of the motor is always the maximum that can be exerted under the corresponding speed. Firstly, the mathematical model of linear induction motor is established, and the analytical expressions of traction and normal force are listed; Then the influence of slip frequency on vehicle tractive performance is analyzed by traction calculation, the VSFC strategy is proposed and its advantages are analyzed. The results show that the VSFC strategy can fully suppress the influence of normal force on levitation stability at low speed, and can give full play to the tractive performance of the motor in the whole process.

Determination of mechanical characteristics of high-speed tracked vehicles traction motor with individual drive wheels

The paper describes the study of electromechanical transmission of tracked vehicles with individual drive wheels. The scheme and analytical dependencies for traction calculation of tracked vehicles are considered. A system of equations that describe a plane motion is given. The required traction characteristics have been built to ensure maximum mobility of tracked vehicles. A developed complex of natural-mathematical modeling, made on the basis of a mathematical model that allows operating in a real time mode is presented. It gives an opportunity to collect statistics of the operating modes of the onboard electric motors and analyze the loading modes. To confirm the theoretical studies, a prototype of a tracked vehicle was developed, which allows determining the torques on the drive shafts of the sides, the rotational speeds of the drive wheels, the longitudinal and lateral accelerations of the hull, the machine’s angular velocity around the vertical axis.

Evaluation of metro stray current corrosion based on finite element model

Leakage currents from DC traction power supply system of metro will reduce the lifetime of the buried pipeline. This study illustrates a real contribution in the analysis of dynamic stray current and the evaluation of the corrosion status of the buried pipeline. The metro locomotives dynamic operation process was established through traction calculation, and then analysed the dynamic influence of stray current distribution under transient finite element model. Finally, a comparison of corrosion influence of stray current is also presented. According to the simulation results, the distribution of stray current is affected by many factors, the relative position of the cathodic protection pipeline and unprotected pipeline has significant influence on stray current.

Urban Rail Transit Scheduling under Time-Varying Passenger Demand

In view of the conflict between the time-variation of urban rail transit passenger demand and the homogeneity of the train timetable, this paper takes into account the interests of both passengers and operators to build an urban rail transit scheduling model to acquire an optimized time-dependent train timetable. Based on the dynamic passenger volumes of origin-destination pairs from the automatic fare collection system, the model focuses on minimizing the total passenger waiting time with constraints on time interval between two consecutive trains, number and capacity of trains available, and load factor of trains. A hybrid algorithm which consists of the main algorithm based on genetic algorithm and the nested algorithm based on train traction calculation and safety distance requirement is designed to solve the model. To justify the effectiveness and the practical value of the proposed model and algorithm, a case of Nanjing Metro Line S1 is illustrated in this paper. The result shows that the optimized train timetable has advantage compared to the original one.

Modeling the train operation of the mainline locomotive

To date, there is a large number of programs that simulate the train operation of the locomotive using the method of traction calculations. As input data in the program, information is entered about the track section, locomotive and train composition. The drawback of modeling the train motion using the traction calculation method is the obtaining of a local unimportant result for a particular section of the track. The article proposes a new approach to modeling the operation of freight mainline locomotive. The train operation of the mainline locomotive is represented by a limited number of generalized modes depending in turn on a limited set of initial conditions - the profile of the track section, the weight of the train, the speed of the locomotive, etc. In this case, the elements of the set of initial conditions are random variables. The advantage of the proposed approach is the ability to give a generalized assessment of the change in the performance of the locomotive train when introducing new elements and control algorithms into the diesel generator unit without linking to a particular section of the track. Comparison of the time of work on the positions of the driver's controller was obtained during the year by mathematical modeling and experienced runs with diesel locomotives of the 2TE116U series at Oktyabrskaya Railway, a branch of the Russian Railways. It showed that the maximum discrepancy between calculated and experimental data does not exceed 5 %. The proposed algorithm for simulating the train operation of the freight mainline locomotive allows reproducing the locomotive train performance parameters with an acceptable accuracy for practice. It can be used to obtain quantitative estimates of the impact of changes in the performance of the train operation of long-distance freight diesel locomotives when new elements and control algorithms are introduced into the diesel generator unit.

Комплексный подход к тяговому расчету ленточных конвейеров

Комплексный подход к тяговому расчету ленточных конвейеров

Optimization of Energy Management Strategy and Sizing in Hybrid Storage System for Tram

In order to design a well-performing hybrid storage system for trams, optimization of energy management strategy (EMS) and sizing is crucial. This paper proposes an improved EMS with energy interaction between the battery and supercapacitor and makes collaborative optimization on both sizing and EMS parameters to obtain the best working performance of the hybrid storage system. This paper demonstrates the whole process of the improvement of the EMS, the traction calculation, the parameter optimization, and the sizing optimization based on real tram and line conditions. The improved strategy is proven to be superior as it guarantees normal operation and avoids shutdown conditions when the supercapacitor is at a low voltage. Furthermore, the optimized sizing result largely decreases the weight of the storage system and obtains a long battery lifespan.

Study of Energy Indicators and Features of Propulsion System Main Components of Electric Vehicle Using Mathematical Simulation

Objectives: To calculate the energy performance of the Electric Propulsion System (EPS) using the mathematical simulation and analysis of the obtained characteristics, taking into account the use of various types of electric motors. Method/ Statistical Analysis: The method of model-oriented programming was used to study the necessary parameters,by which the two mathematical models in Matrix Laboratory (Matlab) / Simulink were built. It allowed the calculations in a short time and a detailed analysis of the results. While building up the mathematical models of electric motors, the vector control was implemented, as based on the method of vector representation in variables of states in a space (Field oriented control). Findings: In addition to mathematical description of the motors, the article represented the mathematical model of the inverter on IGBT transistors required for commutation of the traction motor, lithium-ion battery as well as all major components required for proper system operation. This article discusses two of the most often used type of contactless AC machines - asynchronous motor with squirrel-cage rotor (Induction motor) and a synchronous motor with permanentmagnet excitation (Permanent Magnet Synchronous Motor). Because of mathematical simulation, the assessment of the energy parameters of two systems was carried out. Analysis of the obtained results allowed the identification of characteristic points in driving cycle, defining the minimum requirements for mechanical, electrical and power parameters of the electric propulsion of the electric vehicle on condition of implementation of the cycles reviewed. Because of the traction and energy calculation, the consumption values of electric energy for the electric power source were obtained,including the amount of energy regeneration. Application/improvement: These methods of mathematical models are universal and can be applied to various types of transport, from electric vehicles to electric trucks and electric buses.

ANALYSIS OF INFLUENCE OF DESIGN CHARACTERISTICS OF INCLINED BUCKET ELEVATOR ON THE POWER OF ITS DRIVE

Purpose.One of the main elements of the inclined belt bucket elevators is their drive. To determine the drive power, it is necessary to carry out calculations according to standard methods, which are described in the modern literature. The basic design parameters are the productivity, lifting height, type and properties of the transported material, the angle of inclination. It is necessary to build a parametric dependence of the driving power of the elevator on its design parameters, which takes into account the standard sizes and types of buckets and belts. Methodology. Using the methodology of traction calculation of inclined belt bucket elevator there were built parametric dependences of efforts in specific points of the route of the elevator, as well as the parametric dependences of the drive power of high-speed elevators with deep and shallow buckets on their design parameters and characteristics. Findings. On the basis of constructed parametric dependencies, it was found that the function of changing the value of the elevator’s power from design capacity (at fixed lifting height, type of cargo, belt speed) is piecewise constant and monotonically increasing. It was built a graphical representation of elevator drive power on the angle of its inclination within acceptable limits of change. The resulting relationship is non-linear and monotonically decreasing. In general terms the intervals of project performance values, which provide a constant value of drive power of inclined elevator were defined. As an example of the obtained results it was observed the process of dependence construction of the drive power on design capacity and inclination angle of the elevator for transporting the fine coal. Originality. For the first time there were constructed the parametric dependences of drive power of inclined bucket elevator on its design parameters that take into account the standard sizes and types of buckets and belts. Practical value. Using the constructed dependencies enables relatively quick determination of the approximate value of the drive power of high-speed inclined elevators with deep and shallow buckets at the design stage and high-quality selection of its basic elements in the design of specific characteristics: type of cargo, productivity, lifting height, angle of inclination.

Train movement simulation by element increment method

SummaryThe article presents an element increment method that is developed by current time increment method of train traction calculation. A railway route was divided, breaking it down into elements of different lengths. A whole train movement simulation curve (v–t curve and v–S curve) was formed by splitting the joints of each of the elements' individual simulation curves. During this process, the train velocity variance was calculated by time increment method with assistance of polynomial fitting technology. Additionally, a step‐by‐step method with iteration was used to combine each element and makes the whole simulation curve continuous. Meanwhile, the energy‐saving issue was also taken into account to optimize the simulation curve. This article gives more details about the modeling by providing an example of a railway route based on moving block control. The element increment method is a more effective way to calculate train traction of high‐speed railway, and it is an alternative method to train movement simulation for aiding macroscopic railway transportation planning. Copyright © 2017 John Wiley & Sons, Ltd.

Energy Consumption Modeling and Optimization of Traction Control for High-speed Railway Trains

The energy consumption modeling and the optimization solution for the traction control of high-speed trains are addressed in this paper. Based on the analysis of the operation process, an improved train traction analysis with the multi-mass modeling approach is presented, and the corresponding energy consumption model is investigated. By considering the issues of the passenger comfort and traveling time, an optimization algorithm for traction control of the high-speed trains is presented by using a multiobjective-fitness particle swarm optimization technique. Simulations are performed with practical parameters of the CRH EMU (Electric Multiple Unit) and railway line, and the results demonstrate the performance of the proposed solution over the conventional traction calculation method.

Algorithm Design and Simulation of the Urban Rail Turn-Back Capacity Based on CBTC

In order to analyze the turn-back capacity of urban rail transit based on CBTC more accurately, firstly, this paper analyzes the turn-back process and characteristics, and the factors that influence the turn-back interval time. Secondly, it respectively analyzes various influence factors and designs algorithm. Then, it designs algorithm and developed computer simulation system (TBSim) for calculating the turn-back capacity based on CBTC and the traction calculation. Finally, it proves the correctness and practicability of the algorithm and the simulation system by an example.

Influence of Inter-Stop Transport Distances of a Freight Train upon Its Traction Energy Cost Intensities for Different Target Speeds

Based on train traction calculation theories, this research first simulates the transports of a typically formed freight train hauled by representative types of freight locomotives in China. Accordingly, the exact change of the traction energy cost intensity of the train in the effect of its inter-stop transport distance is analyzed in a quantificational way for different target speeds. It is found that the inter-stop transport distance of a freight train should be no shorter than 20.00 kilometers in order to decrease the traction energy cost per unit transport especially for a relatively high target speed. As a result, it is suggested that the railway freight transport work ought to try its best to utilize a heavy load train in view of its average inter-stop transport distance of the whole trip and its comparatively energy-saving target speeds. Furthermore, as for the transport operation of a railway network, the requirements to the time of each transport work of a train and so on should also be considered for its traction energy saving in an integrated manner.