Wheel Coupling Research Articles

СОВЕРШЕНСТВОВАНИЕ ТРАНСМИССИИ АВТОТРАКТОРНОЙ ТЕХНИКИ С ЦЕЛЬЮ ПОВЫШЕНИЯ ПРОХОДИМОСТИ

The article presents the results of the analysis of the designs of existing differentials of automotive equipment, as well as the processes of their operation. The analysis carried out in this work made it possible to identify the problem, and then solve it by installing two variators in the differential, which made it possible to divide the power flow supplied to the differential, with the ability to track the moments of adhesion of the wheels to the road by changing the internal gear ratios of the power chains supplied to the right and left wheels, independently of each other. The conducted research made it possible to solve an urgent engineering problem, which consists in the development of an inter-wheel differential with a variable gear ratio, ensuring the optimal nature of the connection between the driving wheels and allowing to increase the patency of automotive equipment, while maintaining other positive operational properties due to the full use of wheel coupling with the road. The article also describes the developed design of a differential with a variable internal gear ratio, presents its kinematic scheme, where you can see how the torque is distributed in proportion to the drag forces on the wheels.In conclusion, the article presents the main conclusions of the work done, which consist in increasing the patency of automotive equipment due to the full use of wheel coupling, especially with wet ground. All this will lead to an increase in the efficiency of automotive equipment, the effectiveness of its use in the field (off-road) and lower fuel costs.

ВЛИЯНИЕ РЕЖИМОВ ДВИЖЕНИЯ ЛЕСОВОЗНОГО АВТОПОЕЗДА ПРИ ВЫВОЗКЕ ЛЕСОМАТЕРИАЛОВ НА ЭФФЕКТИВНОСТЬ РЕКУПЕРАЦИИ ЭНЕРГИИ В ПНЕВМОГИДРАВЛИЧЕСКОМ СЕДЕЛЬНО-СЦЕПНОМ УСТРОЙСТВЕ

The necessity of increasing the efficiency of logging road trains by reducing the transport costs spent on hauling timber in existing road and climatic conditions is substantiated. A review of scientific research by foreign scientists is presented, which made it possible to identify the most significant factors influencing transportation costs. A promising design of a recuperative pneumohydraulic fifth wheel coupling device has been proposed, which makes it possible to reduce transportation costs by reducing the amount of fuel used by a road train, to increase the reliability of a logging road train by reducing the dynamic loads that occur between its links when driving over uneven surfaces of a logging road. The mathematical model of the movement of a timber tractor with a semi-trailer equipped with the proposed coupling device, under conditions of frequent accelerations and decelerations, over the unevenness of the logging road has been improved, which makes it possible to perform a preliminary assessment of the energy recovery by the proposed device in various modes of transient processes, as well as to investigate the influence of the main parameters of the recuperative pneumohydraulic fifth wheel coupling device for performance indicators. Two computer programs have been developed to study the performance indicators of a recuperative pneumohydraulic fifth wheel coupling under various transient modes of movement of a logging road train with given parameters of roughness of a logging road. It has been established that the use of the proposed coupling device in a logging road train makes it possible, when driving with randomly repeated decelerations and accelerations, to regenerate power up to 6.5 kW, and also to achieve a value of longitudinal acceleration of the semi-trailer relative to the tractor of 0.72 m/s2. Computer modeling made it possible to establish the value of the optimal diameter of the hydraulic cylinder, which provides the highest value of recuperated power at the lowest value of the acceleration of the semi-trailer relative to the tractor.

Analysis of studies of work processes of energy-saving hydraulic drives and devices of highly loaded technological machines and equipment

The analysis of studies of the work processes of energy-saving hydraulic drives and devices was carried out in order to identify effective ways to reduce the dynamic loading and energy intensity of highly loaded technological machines and equipment. When studying the working processes of an energy-saving pneumohydraulic fifth wheel coupling of a timber tractor with a trailer, it was found that the recuperated power was 5.1-5.9 kW, and the average acceleration of the semi-trailer was 0.8 ... 0.81 m/s2. The energy-saving device of the Amkodor 208V front loader, which includes two torsion springs installed between the frame and the boom, reduces energy costs by 26%. The paper presents studies on energy saving during the operation of a hydraulic press with a pump-accumulator power supply. The results of studies of the energy-saving hydraulic drive of a forest manipulator and a chokerless skidding grip are presented. The energy-saving hydraulic drive of the manipulator column makes it possible to reduce the energy consumption of the column rotation by 25% and increase the productivity of the manipulator by 14%, and the chokerless grip hydraulic accumulator stores power in the range of 1.7 ... 2.1 kW. It is concluded that it is expedient to conduct further studies of the dynamics of energy-saving hydraulic drives of load-lifting mechanisms of manipulators of heavily loaded forestry vehicles.

IMPROVEMENT OF GRAIN TRANSPORTATION TECHNOLOGY FROM COMBINES

The article provides a rationale for an improved technological process for transporting grain from grain combines (ЗK) by a semi-trailer dump truck (НП) in an aggregate with a tractor and a saddle trailer. One of the main reserves for increasing the productivity of a combine is to increase the utilization factor of its shift time by using transshipment technology based on interoperation compensators – tractor trailers for reloaders of the PBN-30, PBN-40, PBN-50 brands, etc. and heavy vehicles (AT), in the body which grain is being reloaded outside the field. The lack of technology is significant downtime of vehicles. A comparative analysis of various technological schemes for the operation of the (ЗK) and vehicles showed that the minimum specific duration of harvesting and transport operations is achieved by using a tractor with a tractor to work in the field, subject to the minimum time spent on the formation (uncoupling, hitching) of transport units using a fifth wheel coupling device, which fitted with a trailer. At the same time, vehicles are used as negotiable (НП)s, which makes it possible to organize the continuous operation of tractors in the sections “ЗК – edge of the field” and “edge of the field – grain receiving point”, where possible downtime of the AT is replaced by downtime only of the НП. We have proposed a technical solution containing a temporary redistribution of the mass of grain in the body of the НП by loading it into the front part of the body. At the same time, the rear wheels of the НП are partially unloaded and do not over-compact the soil, and the rolling semi-trailer, equipped with wide-profile low-pressure tires, perceives additional load without significant soil compaction. The theoretical analysis of the rhythm of the processes of grain movement by individual technological links of the harvesting and transport complex made it possible to determine the analytical dependences of the main parameters of these links on the productivity of the grain combine and the volume of its bunker, the nominal load capacity of the НП, the duration of the НП recoupling, the distance of grain transportation, the average technical speed of the tractor and the car. The use of semi-shuttle transporters operating in two stages: in the field and on the road, provides a 1.5-fold increase in the productivity (average output) of the AT, and also eliminates the cost of specialized reloading trailers and double reloading of grain.

АНАЛИЗ ВЛИЯНИЯ РЕЖИМОВ ДВИЖЕНИЯ ЛЕСОВОЗНОГО ТЯГАЧА С ПОЛУПРИЦЕПОМ НА НАГРУЖЕННОСТЬ СЕДЕЛЬНО-СЦЕПНОГО УСТРОЙСТВА

The article presents the advantages of timber tractors with semi-trailers in comparison with single timber vehicles. The existing road condi-tions for the operation of saddle road trains in-volved in the transportation of timber to con-sumers are described. The causes and conse-quences of loading elements of saddle-coupling devices of road trains are considered. The de-pendences of the change in forces in the cou-pling device on the values of the coefficients of adhesion and the distribution of braking forces, the deceleration of the saddle road train, and also on the height of the center of gravity of the semi-trailer of the road train are presented. The regularities of changing the braking distance, deceleration and compression force in the fifth wheel coupling device of a road train due to un-derutilization of the coupling weight of a tractor with a semi-trailer are considered. The depend-ences of changes in loads in the fifth wheel cou-pling on road conditions, the load of the road train, the location of the fifth wheel coupling on the tractor, as well as on the damping coefficient are analyzed. An analysis of oscillograms of changes in forces in the pivot of the device in the process of sharp braking on a curvilinear and rectilinear trajectory with various options for braking by individual links is given. The influ-ence of the road train load, the speed of its movement, the type of road surface, the design parameters of the coupling device, the presence of lubricant on the base plate, the level of its wear on the change in the moment of resistance in such a device are described. The necessity of increasing the efficiency of timber tractors with semi-trailers by improving the existing designs of fifth wheel couplings is substantiated.

IMPROVEMENT OF GRAIN TRANSPORTATION TECHNOLOGY FROM COMBINES

The article provides a rationale for an improved technological process for transporting grain from grain combines (ЗK) by a semi-trailer dump truck (НП) in an aggregate with a tractor and a saddle trailer. One of the main reserves for increasing the productivity of a combine is to increase the utilization factor of its shift time by using transshipment technology based on interoperation compensators – tractor trailers for reloaders of the PBN-30, PBN-40, PBN-50 brands, etc. and heavy vehicles (AT), in the body which grain is being reloaded outside the field. The lack of technology is significant downtime of vehicles. A comparative analysis of various technological schemes for the operation of the (ЗK) and vehicles showed that the minimum specific duration of harvesting and transport operations is achieved by using a tractor with a tractor to work in the field, subject to the minimum time spent on the formation (uncoupling, hitching) of transport units using a fifth wheel coupling device, which fitted with a trailer. At the same time, vehicles are used as negotiable (НП)s, which makes it possible to organize the continuous operation of tractors in the sections “ЗК – edge of the field” and “edge of the field – grain receiving point”, where possible downtime of the AT is replaced by downtime only of the НП. We have proposed a technical solution containing a temporary redistribution of the mass of grain in the body of the НП by loading it into the front part of the body. At the same time, the rear wheels of the НП are partially unloaded and do not over-compact the soil, and the rolling semi-trailer, equipped with wide-profile low-pressure tires, perceives additional load without significant soil compaction. The theoretical analysis of the rhythm of the processes of grain movement by individual technological links of the harvesting and transport complex made it possible to determine the analytical dependences of the main parameters of these links on the productivity of the grain combine and the volume of its bunker, the nominal load capacity of the НП, the duration of the НП recoupling, the distance of grain transportation, the average technical speed of the tractor and the car. The use of semi-shuttle transporters operating in two stages: in the field and on the road, provides a 1.5-fold increase in the productivity (average output) of the AT, and also eliminates the cost of specialized reloading trailers and double reloading of grain.

Sextic tensor model in rank 3 at next-to-leading order

We compute the four-loop beta functions of short and long-range multi-scalar models with general sextic interactions and complex fields. We then specialize the beta functions to a U(N)3 symmetry and study the renormalization group at next-to-leading order in N and small ϵ. In the short-range case, ϵ is the deviation from the critical dimension while it is the deviation from the critical scaling of the free propagator in the long-range case. This allows us to find the 1/N corrections to the rank-3 sextic tensor model of [1]. In the short-range case, we still find a non-trivial real IR stable fixed point, with a diagonalizable stability matrix. All couplings, except for the so-called wheel coupling, have terms of order ϵ0 at leading and next-to-leading order, which makes this fixed point different from the other melonic fixed points found in quartic models. In the long-range case, the corrections to the fixed point are instead not perturbative in ϵ and hence unreliable; we thus find no precursor of the large-N fixed point.

Research on dynamic response of metro vehicles based on different coupling damage conditions of wheels

Wheel profile wear (WPW), out-of-roundness (OOR), and wheel diameter difference (WDD) are three common types of damage to subway wheels, and each has its own set of operational restrictions. However, in the actual operation, the same wheel is frequently accompanied by multiple forms of damage and the various forms of damage interact with each other. Considering the characteristics of this damage, this paper aims to investigate the influence law and characteristics of wheel coupling damage on the vehicle dynamic performance, as well as the differences in the vehicle performance response caused by the two main coupling conditions, namely, OOR coupling WDD and WPW coupling WDD. The results reveal that the vehicle performance reaction generated by WPW coupled with WDD is more substantial than the vehicle performance response caused by OOR combined with WDD. Furthermore, while the wheel coupling damage deteriorated several of the vehicle dynamic performance indicators, it also enhanced some of the performance parameters during vehicle operation to some extent. The experiments demonstrate that the presence of WDD minimises the peak of wheel/rail lateral force caused by OOR and suppresses the deterioration of the ride comfort index caused by the rise of WPW.

РЕЗУЛЬТАТЫ ИССЛЕДОВАНИЯ ДВИЖЕНИЯ ЛЕСОВОЗНОГО АВТОПОЕЗДА, ОБОРУДОВАННОГО СЕДЕЛЬНО-СЦЕПНЫМ УСТРОЙСТВОМ С ПРУЖИННЫМ АМОРТИЗАТОРОМ

Based on the analysis of scientific works of foreign authors, the main factors influencing the efficiency of the operation of timber tractors with semi-trailers have been identified. A promising design of a fifth wheel coupling with a spring shock absorber for timber tractors with semi-trailers that haul timber in difficult road conditions is proposed. A mathematical model of the movement along a logging road of a logging tractor with a semi-trailer equipped with a fifth wheel coupling with a spring shock absorber has been developed. Based on the developed computer program, a preliminary assessment of the performance indicators of the proposed design of the coupling device was carried out. It has been established that the spring shock absorber of the fifth wheel coupling provides, during braking and acceleration, a decrease in the amplitude of acceleration oscillations between a timber tractor and a semi-trailer with timber in the range from 0.95 to 0.6 m/s2. It was found that in order to reduce unfavorable vibrations of a semi-trailer with timber relative to a timber tractor, it is advisable to use dry friction in a spring shock absorber.

ОЦЕНКА АКТУАЛЬНОСТИ ИСПОЛЬЗОВАНИЯ В КОНСТРУКЦИИ ЛЕСОВОЗНОГО ТЯГАЧА С ПОЛУПРИЦЕПОМ РЕКУПЕРАТИВНОГО ПНЕВМОГИДРАВЛИЧЕСКОГО СЕДЕЛЬНО-СЦЕПНОГО УСТРОЙСТВА

The main advantages of using timber tractors with semitrailers in comparison with single timber trucks and timber trucks with trailers are listed. The analysis of the results of scientific works of foreign authors engaged in increasing the efficiency of timber haulers with semi-trailers in the process of hauling timber is carried out. The existing conditions for the transportation of timber in the Russian Federation by timber haulers with semitrailers are considered. Described are the negative consequences that are manifested in the process of movement on forest roads, limiting the efficiency of using timber tractors with semi-trailers. Among them, the most significant one is highlighted, which consists in the occurrence of significant efforts when braking a timber tractor with a semitrailer in a fifth wheel coupling, accompanied by the appearance of cracks in the elements of the supporting system, breakdowns in the coupling device, as well as folding of the timber road train. The schemes of forces acting on a timber tractor with a semitrailer during braking are presented. The dependences of the change in the braking forces of the axles of a timber tractor with a semitrailer are given, taking into account the non-simultaneous operation of their braking mechanisms, as well as the change in the force in the fifth wheel coupling of a timber tractor with a semitrailer during braking. In order to increase the efficiency of a logging tractor with a semitrailer, a promising design of a recuperative fifth wheel coupling has been proposed.

МОДЕЛИРОВАНИЕ РАБОТЫ РЕКУПЕРАТИВНОГО ПРУЖИННО-ГИДРАВЛИЧЕСКОГО СЕДЕЛЬНО-СЦЕПНОГО УСТРОЙСТВА, РАЗМЕЩЕННОГО В ПОЛУПРИЦЕПЕ ЛЕСОВОЗНОГО АВТОПОЕЗДА

The substantiation of the necessity of using timber trucks, consisting of timber tractors with semi-trailers, when transporting timber, is given. Attention is focused on improving the efficiency of the functioning of log trucks by con-structive improvement of the fifth-wheel couplings used in them. The analysis of scientific works of foreign scientists engaged in the study of the influence of fifth- wheel coupling on the efficiency of log trucks is carried out. A promising scheme of a recuperative spring-hydraulic fifth-wheel coupling, located in the front part of the semi-trailer frame of a timber tractor, is proposed, which has significant advantages in comparison with other similar devices. At the first stage, a mathematical model of the proposed fifth-wheel coupling was developed; at the second stage, a computer program for a preliminary assessment of the efficiency of the functioning of a timber tractor with a semitrailer equipped with a recuperative spring-hydraulic fifth-wheel coupling is made. The dependences of the change in the average values of the recuperative power and longitudinal acceleration of the trailer relative to the timber tractor on the inner diameter of the hydraulic cylinders of the recuperative device, the mass of the semi-trailer and the frequency of braking and accelera-tion of the timber road train are obtained. It was revealed that the optimal diameter of the hydraulic cylinders of the recuperative device for the given conditions, providing the maximum recuperative power, should be in the range of 50-60 mm. It was found that with an increase in the mass of a semitrailer of a logging tractor, as well as with an increase in the frequency of braking and acceleration, an increase in the recovered power is observed

РЕЗУЛЬТАТЫ ИМИТАЦИОННОГО МОДЕЛИРОВАНИЯ ПРОЦЕССА ПОДАЧИ И РАСПРЕДЕЛЕНИЯ СМАЗОЧНОГО МАТЕРИАЛА В СЕДЕЛЬНО-СЦЕПНОМ УСТРОЙСТВЕ ЛЕСОВОЗНОГО ТЯГАЧА С ПОЛУПРИЦЕПОМ

The necessity of increasing the efficiency of the fifth wheel coupling of hauling tractor with saddle trailer has been substantiated. The analysis of the works of foreign scientists investigating the influence of fifth wheel couplings on the efficiency of functioning of road trains has been carried out. The importance of periodically applying the lubricant recommended by the manufacturer to the rubbing surfaces of the base plate and the saddle of the fifth wheel coupling of hauling tractor has been described. The goal of the work is formulated to determine the optimal number of outlets in the seat for supplying the minimum amount of lubricant that ensures full coverage of the seat surface, as well as long-term retention on it. To achieve this goal, a mathematical model and a computer program based on it have been developed. The schemes of representation in the model of the mounting plate of the hauling tractor and the base plate of the saddle trailer, the interface form with the results of modeling the supply and distribution of lubricant over the rubbing surfaces of the fifth wheel coupling, as well as a diagram of the main input and output parameters of the simulation model are given. The time dependences of the coefficient of lubricant coverage of the mounting plate of the fifth wheel coupling seat with different periodicity of lubricant supply through a variable number of outlet openings are obtained. It was found that the increase in the coefficient of coverage of the mounting plate of the fifth wheel coupling with a lubricant over time occurs according to an exponential law. The optimum number of openings for the lubricant supply is 5-7

ИМИТАЦИОННОЕ МОДЕЛИРОВАНИЕ РЕКУПЕРАТИВНОГО ПРУЖИННО-ГИДРАВЛИЧЕСКОГО СЕДЕЛЬНО-СЦЕПНОГО УСТРОЙСТВА ЛЕСОВОЗНОГО ТЯГАЧА С ПОЛУПРИЦЕПОМ

The importance of using timber road transport in the technological process of harvesting and hauling timber has been substantiated. The influence of the design flaws of fifth-wheel couplings on the safety indicators of the road train, its stability, productivity, and fuel consumption, which are manifested during the operation of timber tractors with semitrailers, has been revealed. The work of foreign authors aimed at improving the efficiency of using fifth-wheel couplings used in the designs of tractors with saddle trailer has been considered. The advantages of using the proposed recuperative spring-hydraulic fifth-wheel coupling device in a timber lorry train have been described. They consist in ensuring a simultaneous increase in the reliability of road train, recuperating energy of the working fluid, reducing the magnitude of dynamic loads, as well as ensuring favorable working conditions for the driver. On the basis of the developed mathematical and simulation functioning models of a timber tractor with a saddle trailer equipped with the proposed design of a recuperative spring-hydraulic fifth wheel coupling, computer experiments have been carried out, which made it possible to obtain the dependence of the influence of the inner diameter of the hydraulic cylinder, the stiffness of the springs used in the recuperative spring-hydraulic fifth wheel coupling on the longitudinal acceleration of the semitrailer and the average value of the recovered power. It was revealed that the optimal spring stiffness of the recuperative spring-hydraulic fifth wheel coupling, which is in the range from 150 to 200 kN/m, makes it possible to achieve the value of the average recovered power in the range from 7 to 8.4 kW

Development of the conceptual design of vehicles for off-road container transportation for mining applications

The article substantiates the relevance of off-road container transportation by ground railless transport vehicles and weight-size parameters of the transported cargo for the mining operations. A hierarchy of complex mobility properties is developed to investigate the significance of performance properties, which is divided into levels of properties. Taking into account the hierarchy of properties, the measuring instruments are determined, the indicators of which can be used to determine the priority technical solution for container and rock transportation vehicles. The article provides a classification of tracked vehicles and tracked trains with the analysis of their design and layout variants. As a result, variants of the concepts of vehicles for off-road container and rock transportation have been formed. Based on the analysis of the hierarchy of performance properties, design and layout variants of modern tracked vehicles and considering the selected objects of research, the conceptual design of a semi-trailer tracked train and a tracked train with a double-hinge fifth wheel coupling has been proposed.

ПЕРСПЕКТИВНАЯ КОНСТРУКЦИЯ РЕКУПЕРАТИВНОГО ПРУЖИННО-ГИДРАВЛИЧЕСКОГО СЕДЕЛЬНО-СЦЕПНОГО УСТРОЙСТВА ЛЕСОВОЗНОГО ТЯГАЧА С ПОЛУПРИЦЕПОМ

The relevance of the development and use of new promising designs of fifth wheel coupling devices for forestry tractors with semitrailers, aimed at ensuring the simplicity of the design of fifth wheel coupling devices, their high reliability, safety in work, reducing metal consumption and the possibility of accumulating and using energy that is not efficiently dissipated into the environment, is substantiated. The operating conditions of timber tractors with semitrailers for timber removal are described. The main transients occurring in the fifth wheel coupling and contributing to the emergence in it of large dynamic loads from the inertia of the mass of the semitrailer are given. A promising design of a recuperative spring-hydraulic fifth wheel trailer truck with a semitrailer is proposed, which allows to reduce the energy losses that occur in the fifth wheel trailer, to accumulate and is useful to use in the hydraulic drive of the manipulator during the loading and unloading of timber. The device and operation of the regenerative spring-hydraulic fifth wheel coupling are described. It was revealed that the use of the proposed device will improve ride smoothness and reduce fuel consumption of the forest tractor with a semitrailer, as well as provide more favorable conditions for the driver to work.

Dynamical processes in a multi-motor gear drive of heavy slabbing mill

A real case study is represented of abrupt failures in a new multi-motor gear drive of vertical rolls in the heavy slabbing mill. Modal analysis is conducted, and the lowest torsional vibration modes are verified by the data from an industrial plant. Conditions of parametric resonances due to variable stiffness of teeth are determined within the range of working speed. The branched gear drive is investigated by the non-linear dynamical model with backlashes. It is shown that instantaneous dynamic loads in driveline are strongly dependent on the difference in gap sizes and phase shift between two intermediate gears in the output gear wheel coupling. Deviation in electrical parameters by 0.5 % is considered as the additional cause of not equal load sharing of parallel motors. Results of this research allowed preventing further failures of the gearbox and optimizing slabbing mill control. The proposed approach can be used in other multi-motor machines.

Failure analysis of the fifth wheel couplings utilized in heavy semi-trailer tractors

Fifth wheel coupling is a key component of heavy duty semi-trailer tractor, providing the link between the semi-trailer and the towing tractor. In the present work, the failure of fifth wheel coupling utilized in heavy duty semi-trailer tractors was analyzed. Firstly, the chemical composition and metallographic microstructure of the material of the fifth wheel coupling were characterized using scanning electron microscopy with an energy dispersive spectrometer. Secondly, the mechanical properties of the material was investigated by tensile tests on specimens manufactured out from the failed fifth wheel couplings. Thirdly, the stress distributions of the fifth wheel coupling under typical loading conditions were obtained via multibody dynamics analysis and finite element analysis. Finally, crack morphology and fracture surface were examined. Results showed that the chemical composition, metallographic microstructure and mechanical properties of the matrix material were in accordance with standard requirements, which rules out the possibility that the failures were caused by casting defects in the matrix material. Stresses in the crack regions were in tensile stress state under different loading cases and were much smaller than both the mechanical strength and fatigue strength of the material. Therefore, the failure of the fifth wheel couplings was attributed to stress corrosion cracking induced by tensile stress and damp environment. Measures to prevent such failures were discussed in details as well.

MODEL OF THE TRACTION ASYNCHRONOUS ELECTRIC DRIVE IN THE MODE ELECTRODYNAMIC BRAKING WITH A SCALAR CONTROL SYSTEM

This article is devoted to the problem of traction asynchronous electric drive operation in normal and abnormal conditions in the mode of electrodynamic braking. The proposed simulation model allows us to study the dynamical processes that arise in a traction asynchronous electric drive while driving on sections with different coupling coefficient of wheel pairs with a rail. The simulation model is rather versatile, which allows us to analyze in detail the electromagnetic and electromechanical processes occurring in a frequency controlled driven asynchronous electric drive taking into account changing conditions of rolling stock operation in electrodynamic braking, to evaluate the energy and operational parameters, to investigate the influence of parameters of the frequency converter, traction engine, parameters links of direct current to the nature of the transition processes, using modern methods of mathematics some simulation. As an example, the results of the simulation of a traction asynchronous electric motor with a scalar control law in the mode of electrodynamic braking with stabilization of the voltage in the DC link and the control of the braking effort, depending on the coupling coefficient of the wheel coupling with the rail, are given. The proposed system of protection against excessive slipping and skid wheel pairs can prevent the occurrence of abnormal operating mode of the traction asynchronous electric drive in the mode of traction and electrodynamic braking with a sharp change in the coupling coefficient of the wheel coupling with a rail, to identify the restoration of a satisfactory coupling coefficient and to analyze the need for adjusting the traction and braking torque of the traction asynchronous electric motor depending on the condition of the surface of the rails.

Increasing the stability of the articulated lorry at braking by locking the fifth wheel coupling

The jackknifing of the articulated lorry is determined by the loss of stability with respect to the vertical axis of the fifth wheel coupling, which can be caused by the failure of the brake system, the displacement of the center of mass of the semitrailer or tractor from the longitudinal axis of the vehicle, the road parameters (longitudinal and transverse slopes), the difference in the friction coefficients under the sides of the articulated lorry. In this regard, the issue of creating devices that prevent the jackknifing, and their control systems is important. A method is proposed for maintaining the stability of the movement of articulated lorry when braking both on a straight line and in a turn by blocking the relative rotation of the tractor and the trailer. Blocking occurs due to the creation of a stabilizing moment in the direction opposite to the angular rate of folding. To test the developed algorithm for locking the fifth wheel coupling, a mathematical model of the spatial motion of the articulated lorry was developed, including the models of interaction of an elastic tire with a rigid terrain, suspension systems, transmission, steering, fifth-wheel coupling. The efficiency and effectiveness of the coupling locking control system is proved by comparing the results of the simulation of a straight-line braking and braking in turn. It is shown that the application of the control system significantly increases the stability of the road train.

Kinematic Analysis of Tractor-Semitrailer with Split Fifth Wheel Coupling During Low Speed Turning Maneuvers

Kinematic Analysis of Tractor-Semitrailer with Split Fifth Wheel Coupling During Low Speed Turning Maneuvers