Wheel Tire Research Articles

Effects of Wheel and Tire Selection on High-Strength Lightweight Manual Wheelchair Propulsion Cost Using Robotic Propulsion

<h3>Research Objectives</h3> To investigate the effects of wheel and tire selections on the propulsion characteristics of a high-strength lightweight manual wheelchair, a robotic propulsion device was deployed across a cohort of wheelchair configurations. <h3>Design</h3> This experimental study compared the mechanical behaviors of four wheelchair configurations with differing drive wheels and casters. <h3>Setting</h3> This study was conducted in a laboratory setting. Test surfaces (linoleum tile, low-pile carpet) represented common environments where high-strength lightweight wheelchairs are used. <h3>Participants</h3> No human subjects were used in this study. One high-strength lightweight wheelchair frame (Viper Plus GT, Drive Medical) was used for all four configurations. The baseline configuration reflected the default manufacturer configuration, comprising a solid mag drive wheel and solid 8"x1" caster. The other three configurations included Primo 6"x1.5" caster wheels and solid 24"x1-3/8" Primo XPress drive tires. <h3>Interventions</h3> The Anatomical Model Propulsion System (AMPS) robotic wheelchair tester propelled the chair using pre-generated straight and curvilinear maneuvers using repeatable and reliable cyclic torque profiles across tile and carpet. <h3>Main Outcome Measures</h3> The main outcome measure was propulsion cost, defined as the ratio of mechanical energy required to propel the wheelchair to the total distance traveled over-ground, reported in Joules per meter. In addition, the metric of 'value' – the retail cost of components in comparison to their relative impact on the energetic propulsion cost – was proposed for the first time in relation to high-strength lightweight wheelchair components. <h3>Results</h3> Results indicate significant reduction in propulsion cost across all maneuvers and surfaces with upgraded casters (<24%), drive wheel tires (<23%), or both (<41%). The total retail cost differential between the full sets of default components and upgraded components was $33 (USD). <h3>Conclusions</h3> This study demonstrated that better casters and drive wheel tires can improve the performance of high-strength lightweight wheelchairs and better meet the mobility needs of users. Furthermore, gaining knowledge of component-level energy losses could inform users, clinicians, and manufacturers on 'better' components that are available in each context of use. <h3>Author(s) Disclosures</h3> The authors do not have any conflicts to disclose.

Preventive Renewal Model with Diverse Maintenance Activities

Abstract The paper presents a developed computational model based on decision- random models, which allows us to develop a strategy for preventive renewal of complex technical objects whose maintenance activities cover various actions. Depending on the renewal type, diversification of the cost and maintenance time may influence the interval at which preventive renewal should be performed. The developed algorithm takes into account the predicted time of proper operation based on the probability distribution of operating time to failure, as well as the cost of each preventive action and potential failure. The defined strategy is a set of activities that must be performed every specified time interval in a manner that is economically justified and minimizes the risk of failure. The technical object on which the model is discussed is the wheel tyre of a rail vehicle.

Deformation behaviour and microscopic investigations of cyclically loaded railway wheels and tyres

Abstract Railway wheel and tyre steels were investigated by specimens from defined volume sections representing the local microstructure of original components. As a consequence of the industrial heat treatment and the size of the components, microstructural gradients exist in the wheel rim and tyre crosssection. The ferrite fraction of the ferritic – pearlitic microstructure and the cementite lamellae spacing vary depending on the distance to the running surface (tread). Stress-controlled load increase and single-step push– pull tests were carried out at ambient temperature with servohydraulic testing systems to study fatigue phenomena with special consideration of microstructural details. Mechanical stress– strain hysteresis, thermometrical, and electrical measurements were used for a comprehensive characterization and evaluation of the cyclic deformation behaviour. The measured physical quantities show a strong interrelation with the underlying fatigue process. Light, scanning, and transmission electron microscopy (TEM), together with digital image processing, allow to interpret the measured data on the basis of microstructural details. In defined fatigue states, TEM investigations were performed to correlate the loading conditions with the appearing dislocation structures.

Исследование параметрических резонансных колебаний в ходовой части гусеничной машины

Nowadays increased requirements to modern high-speed tracked vehicles are imposed on various operational and functional characteristics. In particular, special requirements are imposed on the level of oscillation load, which determines the performance of various structural elements of the caterpillar drive, the suspension system, and other components and assemblies of machines, including additional equipment mounted on the base chassis. In the proposed paper, the interaction of the caterpillar drive with the road wheel when moving on hard soils is considered, as one of the main sources of the formation of high-frequency oscillation loading of the machine. A connection is established between the parametric change in the rigidity of the elastic interaction of the road wheel and the rubberized treadmill with increased dynamic and thermal tension of the massive tires of the road wheels. A complex of mathematical models for the numerical determination of the oscillation and thermal loading of road wheels is being developed, the stability of the obtained periodic solutions is estimated based on the analysis of parametric oscillations using the Ains-Strett diagram. On the basis of the research results, the necessary value of the modulation depth of the elastic interaction stiffness is substantiated, which ensures the elimination of parametric resonances. It is shown that the displacement of the gaps between of trucks by giving it a “zigzag” shape increases the elastic convergence of the axle of the road wheel with the rubberized treadmill in the area of the rubber-metal hinges. This makes it possible to reduce the modulation acceleration parameter μ (and, accordingly, the parameter of the Aynes-Strett diagram) by 40 %, which reduces the likelihood of excitation of resonant oscillation parameters when using a road wheel massive tire and a rubberized treadmill. In addition, the paper presents the results of an experimental study of the thermal stress of the massive tires of road wheels of high-speed tracked vehicles. The existing method for calculating the thermal stress of the massive tires of road wheels is analyzed, phenomena that are not taken into account in this method are revealed, but which have a significant effect on the change in the temperature of the inner layers of massive tires of high-speed tracked vehicles.

ДОСЛІДЖЕННЯ ПРОХІДНОСТІ ВАНТАЖНИХ АВТОМОБІЛІВ НАЦІОНАЛЬНОЇ ГВАРДІЇ УКРАЇНИ З КОЛІСНОЮ ФОРМУЛОЮ 6×6

A study of the patency of trucks of the National Guard of Ukraine, with a wheel formula 6 × 6, which has significant features. The operation of trucks of the National Guard of Ukraine involves traffic on both general and off-road roads. Possibilities of increase of patency, at the expense of maintenance of optimum redistribution of air pressure in tires of wheels are investigated. Improving patency in difficult operating conditions can be investigated using a modern mathematical apparatus. This will allow for the vehicles of the National Guard of Ukraine to investigate the patency and choose its optimal parameters when performing combat missions in various operating conditions and with a certain ratio of their technical characteristics. Formulation of the problem. As a result of the full-scale war of the Russian Federation against Ukraine, the Armed Forces of Ukraine and the National Guard of Ukraine faced more serious technical requirements than in peacetime. Among such requirements is maneuverability - which in turn is provided by controllability, speed and patency. The patency of trucks of the National Guard of Ukraine depends on many factors, the main of which are: the type and quality of surfaces on which traffic is carried out, air pressure in the tires, weight of the car, the order of passage in the column, and many others. At the National Guard of Ukraine high-pass truck have been widely used system of centralized regulation of air pressure in the tires, but the main disadvantage of such systems is that to increase the patency of low-bearing bearing surfaces need to reduce tire pressure to the minimum allowable, which in in turn imposes restrictions on the maximum speed due to the risk of the tire coming off the rim, overheating and explosion. To ensure the required level of patency, it is advisable to determine the influence of various factors.

Research on intervention criterion and stability coordinated control of AFS and DYC

To improve vehicle handling stability, an intervention criterion and a coordinated control method for active front steering (AFS) and direct yaw moment control (DYC) are proposed. First, the intervention criterion of AFS/DYC stability control based on the working state of lateral tyre force is proposed. Next, a 7-DOF (degree-of-freedom) dynamics model is established, and a method for identifying nonlinear pure lateral force model based on onboard sensors and vehicle handling stability experiment is developed. Then, the mapping relationship between lateral tyre force saturation point and wheel angle is constructed to rapidly judge the working state of lateral tire force. Subsequently, a UKF-based state observer, a hierarchical control algorithm and the yaw moment distribution coefficient are designed for the proposed AFS/DYC control system. Finally, a fishhook test and a step input test are carried out on low adhesion coefficient roads to verify the effectiveness of the proposed AFS/DYC coordinated control method.

Body Leveling Control Model Establishment and Experiment Analysis

Highlights The vehicle body leveling control model based on tire stiffness and wheel centroid displacement is established in this article.The average pitch angle error is 7.94%, and the tilt angle average error is 4.37%.The body leveling control algorithm developed based on this model can be applied to the automatic leveling control of hilly tractors and cars.Abstract. The body leveling control system is the core part of the attitude control of the hilly mountain tractor. It calculates the body posture in real-time according to the body leveling control model and makes corresponding control strategies. The accuracy of the control model directly affects the vehicle leveling accuracy. This article proposes the leveling control model based on tire stiffness and tire mass displacement. The slope road surface excitation information is collected in the field, and the road surface excitation data is processed appropriately. The accurate road surface excitation information is obtained. The input of the simulation model is displacement data. However, the collected road excitation information is the acceleration signal. Thus, the acceleration signal is converted to the displacement signal through the frequency domain integration method. The comparison between the calculated calculation results and the experimentally acquired attitude data indicates that the average pitch angle error is 7.94%, and the average tilt angle error is 4.37%. Accordingly, the vehicle body leveling control model established in this article is compatible with the experimental results and can accurately output the body posture and develop the body tone. Keywords: Control, Hydraulic, Leveling, Pavement, Road

Процесс взаимодействия эластичной шины c опорной поверхностью дороги, покрытой противогололедным материалом на основе технической соли

When studying the traction properties of the elastic tire, it should be kept in mind that it is the investigation of the lateral reaction formation in the wheel contact patch with the supporting surface when it is moving with a lateral drifting that is particularly important for the researcher. In spite of numerous publications on this problem, there are practically no studies of lateral traction of the elastic wheel tire with a winter slippery road treated with chemical de-icing agent. The purpose of this study is to analyze the process of interaction of the elastic tire with a road surface covered with snow glaze and sand-salt mixture. As a result of this research, three variants of interaction of the elastic tire with the winter road have been revealed based on the different models of friction, namely, boundary, mixed and viscous models of friction, depending on the melting ability of technical salt. When mixed and viscous friction occurs between the tire and the road surface, a «third» body is formed, consisting of a mixture of particles of snow-ice deposits, salt and sand, which is able to slide on the layer of liquid salt solution formed on the supporting road surface, and significantly reduce the tire traction properties when driving with lateral drifting. The obtained results contribute to enlarging new scientific knowledge regarding lateral traction of elastic tires with the supporting surface of the road with winter slipperiness, which is important for increasing the active safety of vehicles on the roads in the cold season.

METHODOLOGY AND ALGORITHM FOR CALCULATING CONTACT PARAMETERS WHEN THE TIRE WHEEL INTERACTS WITH THE BASE

Предложен алгоритм и методика вычисления параметров контакта шины колеса с основанием. Применяя теорию упругости анизотропного тела, строится математическая модель расчета и программа обработки снимка контакта шины с основанием. Проведены экспериментальные исследования.

Features of braking of multi-axle vehicles depending on the layout of their axles

Problem. For an hour, in the scientific-methodical recommendations of the ship-experts, it is installed in the scientific-technical literature of the day-to-day parameters of galvanizing of vantage, bug-capable transport equipment, so that it is inaccurate to introduce autotransport equipment for the eastern part to inaccurate zasob_v unique road transport suit. Goal. The value of the function of galvanizing large transport bridges on the basis of the coordinates of the position to the center of the heavy transport, realizable values, which are realized between the tires and the supporting surface, as well as the support for the rear axle of the transport bridges. Methodology. The approaches adopted in the work to solve this goal are based on the theoretical foundations of braking multi-axle vehicles, the scientific provisions of elastic deformations of pneumatic tires of automobile wheels, geometric and weight parameters of a wheeled vehicle. Results. The equations that allow to calculate the value of the braking coefficient of multi-axle vehicles based on the coordinates of the position of the center of gravity, the realized couplings between the tires and the bearing surface, as well as the load distribution between the respective front and rear axles of the vehicle. Rivnyannya is assigned, which allow the positioning of the coordinates to the center of the car of a multi-axle wheeled transport vehicle for both front and rear axles. The calculation schemes of the position of the coordinates of the center of mass for two-axle, three-axle and four-axle with different axle layout are presented in graphical form, which give a general idea of the mass distribution between the front and rear axles of the vehicle. Originality. Presented in a graphical view of the layout of the positioning of the coordinates to the center of the car for a two-axle, three-axle and one axle with a small layout of the bridges, which give a far-reaching display of the space between the front and rear axles of the transport vehicle. Practical value. The results can be recommended by the experts-auto technicians in the development of technical capabilities for the drivers of vantage transport means, uniqueness of the road-transport usability.

Effects of wheels and tires on high-strength lightweight wheelchair propulsion cost using a robotic wheelchair tester

Purpose This study was designed to investigate the effect of wheel and tire selections on the propulsion characteristics of a high-strength lightweight manual wheelchair using robotic wheelchair propulsion. Materials and methods Four configurations were compared with differing combinations of drive wheel tires and casters, with the baseline reflecting the manufacturer configuration of a solid mag drive wheel and 8"×1" caster. The robotic wheelchair tester propelled the chair using pre-generated straight and curvilinear manoeuvres using repeatable and reliable cyclic torque profiles. Additionally, energy loss of the components was measured using coast-down deceleration tests to approximate the system-level rolling resistance of each configuration. Results Results indicate a significant decrease in propulsion cost, increased distance travelled and increased manoeuvrability across all configurations, with upgraded casters and tires. Conclusions These results indicated that with better casters and drive wheel tires, the performance of high strength lightweight wheelchairs can be improved and better meet the mobility needs of users. Implications for rehabilitation Wheel and tire selection can have a demonstrable impact on the propulsion efficiency of manual wheelchairs Coast-down test protocols can be used as a simple and cost-effective means of assessing representative energy losses across various surfaces Wheelchair configurations can be optimized with proper knowledge of the main energetic loss contributions and the environments and contexts of use

Concept and Development of an Accelerated Repeated Rolling Wheel Load Simulator (ARROWS) for Fatigue Performance Characterization of Asphalt Mixture.

Fatigue performance is one of the most important properties that affect the service life of asphalt mixture. Many fatigue test methods have been developed to evaluate the fatigue performance in the lab. Although these methods have contributed a lot to the fatigue performance evaluation and the development of fatigue related theory and model, their limitations should not be ignored. This paper starts by characterizing the stress state in asphalt pavement under a rolling wheel load. After that, a literature survey focusing on the experimental methods for fatigue performance evaluation is conducted. The working mechanism, applications, benefits, and limitations of each method are summarized. The literature survey results reveal that most of the lab test methods primarily focus on the fatigue performance of asphalt mixture on a material level without considering the effects of pavement structure. In addition, the stress state in the lab samples and the loading speed differ from those of asphalt mixture under rolling wheel tire load. To address these limitations, this paper proposes the concept of an innovative lab fatigue test device named Accelerated Repeated Rolling Wheel Load Simulator (ARROWS). The motivation, concept, and working mechanism of the ARROWS are introduced later in this paper. The ARROWS, which is under construction, is expected to be a feasible and effective method to simulate the repeated roll wheel load in the laboratory.

Stability control of a vehicle with tire blowout based on active steering and differential braking

The vehicle with tire blowout will have dangerous working conditions such as yaw and tail flick, which will seriously endanger the safety of driving. A tire blowout model was established based on the UniTire model and the change of tire blowout mechanical characteristics. A Carsim/ Simulink joint simulation platform was built to study the dynamic response of the vehicle after the front wheel tire blowout under curve driving. A combined control strategy of outer-loop trajectory control and inner-loop differential braking control based on sliding mode fuzzy control algorithms and fuzzy PID control algorithms was proposed to ensure that the vehicle can still follow the original trajectory stably after tire blowout. The results show that the tire blowout of the front wheel on the same side as the turning direction has a great influence on the instability and yaw of the vehicle, and the designed control strategy can effectively control the running track of the vehicle with tire blowout and the vehicle stability.

Теоретичне дослідження стійкості руху асиметричного гичкозбирального машинно-тракторного агрегату

Goal. To determine based on numerical computer modeling of the obtained analytical dependences the parameters of stable plane-parallel motion of an asymmetric top-gathering machine (TGM). Methods. Methods of higher mathematics for the transformation of systems of differential equations, the theory of stability of motion, automatic control, the study of the behavior of tracking systems, a compilation of computer programs, numerical calculations, construction of graphical dependencies and their analysis are used. Results. According to the results of the analytical study, the values are gained of the amplitude and phase-frequency characteristics of the oscillations of the course angle of the tractor during the reproduction of the perturbing unit in the form of oscillations of the angle of rotation of the hitch in the horizontal plane. Based on mathematical modeling data the necessary graphic dependences are constructed. Their analysis made it possible to establish the influence of the working speed of the test unit, the values of the input coefficients of the tires of the front and rear wheels of the tractor, as well as the layout of the power tool (universal or integrated) on the stability of the test unit. Conclusions. Based on the received system of differential equations the stability of movement of the asymmetric TGM during the performance of the technological process is investigated. Quantitative indicators of this stability are the values of the amplitude and phase-frequency characteristics of the oscillations of the course angle of the tractor during the development by the unit of external perturbation in the form of oscillations of the angle of rotation of the TGM. Calculations have shown that reducing the value of the input coefficient of the tires of the tractor wheels increases its sensitivity to the effects of perturbation. This sensitivity is greater the closer the wheels of the power tool are located to the point of attachment of the trailed TGM. From tractors of classical and integral arrangement at the assembly of the asymmetric TGM, the preference should be given to the first one. According to the results of mathematical modeling, the qualitative increase in the speed of the tractor based on tractors of both schemes from 1.5 to 2.5 m/s leads to an undesirable increase in amplitude-frequency response and the desired increase in phase-frequency response during their reproduction of external disturbance in the form of oscillations of the angle of rotation of the TGM. At the same time, in quantitative terms, the sensitivity of the unit based on a classic tractor to the effect of perturbing on the amplitude is 11–12% less, and the phase shift — almost the same, which is the best option in terms of stability of the tractor in the horizontal plane.

Optimization research on arc height of running surface based on reducing partial wear of straddle-type monorail vehicle running wheel tire

This article proposes an ideal of reducing the partial wear of the running wheels by optimizing the arc height of the running surface to improve the wheel-rail contact state. To realize this idea, two kinds of concave and convex running surfaces were designed, the “running wheel-rail beam” finite element model of three kinds of rail surfaces of concave, convex, and plane were established. Taking the arc height of the running surface as the design variable, the total friction work and the friction work deviation (FWD) value as the dual optimization goal, an optimization model of arc height of running surface was established based on finite element model and multidisciplinary optimization platform Modefrontier. An improved genetic algorithm was used and an co-simulation optimization mode was put forward in the optimization. The optimization results show that when the concave height of the inner running surface is 22.62 mm, the total friction work and the FWD values are reduced by 11% and 11.8% respectively; When the convex height of the outer running surface is 11.81 mm, the objection values are reduced by 4.9% and 32.1% respectively. An ideal running surface was obtained and the life of the running wheel was extended by the research.

EXPERIMENTAL RESEARCH OF MICRORELIEF SOIL SURFACES OF PERMANENT TECHNOLOGICAL TRACK

A promising direction for further development of agriculture not only in Ukraine but also in the world is the introduction of innovative technologies, to which we should include the track system of agriculture. The movement of transport and energy vehicles on the aligned compacted trace of the constant technological track causes undesirable and uncharacteristic vibrations for agricultural machinery. The latter are due to the influence of the microprofile of the constant technological track, which has a significant negative impact on the degree of comfort and efficiency of the operator, operational and technological indicators, reliability and smoothness of machines. The method and results of experimental automated estimation of the microprofile of irregularities of traces of the constant technological track are presented in the article. Experimental studies of the microprofile of irregularities of the traces of the constant technological track have shown that the standard deviation of the irregularities of the profile is ± 0.84 According to their internal structure, the inequalities of the profile of traces of the constant technological track are characterized by a function that contains, along with random components, the harmonic ones, which are expressed by attenuating periodic oscillations of the normalized correlation function. The main share of variances of oscillations of the irregularities of the profile of the traces of the technological track is concentrated in the frequency range from 0… 0.3 cm − 1. The generator of formation of irregularities of a longitudinal profile of soil traces of a constant technological track are parameters of ground hooks of tires of wheels of the cars moving on it.This is confirmed by the fact that the length of the correlation of the ordinates of the irregularities of the profile of the traces of a constant technological track in the conditions of tests of the bridge agricultural tool of the new design is about 0.18 m, which corresponds to the pitch of its tires.

A comparative study of the recursive least squares and fuzzy logic estimation methods for the measurement of road adhesion coefficient

ABSTRACT Vehicle active safety system is the hotspot of current research and development, and the road adhesion coefficient is one of the essential parameters in the development of automobile active safety system, which plays a pivotal role in automobile safety. To improve the real-time performance and accuracy of the road adhesion coefficient, this paper proposes different control methods and compares and analyzes them. To accurately estimate the road adhesion coefficient in real-time, an eight-degree-of-freedom vehicle model was adopted in this paper. According to the tire torque and wheel speed, the adhesion coefficient was estimated based on the second-order nonlinear extended state observer. The experimental data, such as slip rate, using the improved tire model, is based on the recursive least squares method with forgetting factor and fuzzy logic algorithm real-time of tire-road friction coefficient estimation. The results show that the observer can effectively observe utilisation adhesion coefficient, and both control algorithms can estimate the road adhesion coefficient in real-time, effectively and quickly. On different roads, the use of the recursive least squares algorithm resulted in higher estimation accuracy, better robustness, and better control effect than using a fuzzy logic algorithm.

The application of dither to mitigate curve squeal

Curve squeal is a highly disturbing tonal sound generated by rail vehicles like trains, metros or trams, when negotiating a sharp curve. The probability that squeal occurs increases with reduced curve radius of the track. Curve squeal noise is attributed to self-excited vibrations caused by stick/slip behaviour due to lateral creepage of the wheel tyre on the top of the rail. With respect to the large number of rolling stock units and the long lifetime of vehicles, there is an urgent need for a cheap and simple retrofitting measure to reduce curve squeal. Therefore, main objective of this paper is to investigate the potential to reduce curve squeal by means of active control in the form of dither in an efficient and robust way. Dither control has been applied in the field of mechanical engineering for systems including non-linear components. There it has been shown to suppress self-excited oscillations very efficiently. The control is an open-loop control. It consists in adding a forced vibration to the vibrational system. A time-domain model has been applied to investigate the mechanisms behind self-excited vibrations leading to curve squeal at the squealing noise rig at Chalmers University of Technology. The analysis showed, that in the presence of constant friction, the coupling between lateral and vertical direction is the driving mechanism for building up self-excited vibrations. Based on this insight, the potential of dither has been investigated. For the case considered here dither has the potential to reduce the overall kinetic energy on the wheel by more than 10 dB and on the rail by more than 20 dB. Further optimisation of dither forces with respect to the radiated sound power might increase this potential.

Soil structure response to field traffic: Effects of traction and repeated wheeling

Soil compaction caused by the use of heavy agriculture machinery in non-optimal soil conditions hampers crucial soil functions. Tyre inflation pressure and wheel load are well-known key drivers of compaction. The effects of traction and repeated wheeling are, however, not yet fully understood but may be of critical importance. We aimed to quantify the effects of traction and repeated wheeling on some soil structural properties independently in a compaction experiment conducted on a sandy loam at a soil water content near field capacity, using a tractor-trailer combination at two loads. The trailer was used in ‘standard’ and ‘offset’ steering modes, the latter referring to the mode in which measurements could be taken for the pass of a single towed and thereby passive trailer wheel (with one, two, three and six wheel passes). Penetration resistance was measured to 0.71 m depth and 100-cm3 soil cores were collected around 0.16 m depth for structural property measurements. In the offset steering mode, the measurements were made in the tractor tracks to investigate the effect of traction and in the trailer’s wheel track to investigate the effect of repeated wheeling (at 6.0 Mg static wheel load). The measurements were also collected for the standard steering configuration with the high towed load and from reference plots. Measurements on the soil cores comprised bulk density, porosity, and air permeability. We found a clear effect of traction on deformation of some soil structural properties, with no significant effects of the low drawbar pull but with substantial effects of the high drawbar pull. Reductions in air permeability and specific permeability were significant (89 % and 83 %, respectively) and indicated a densification and homogenisation of the soil. The effect of repeated wheeling was gradual and reasonably well explained by a linear fit to the number of wheel passes. After six passes with the passive wheel caused some soil structural properties to differ significantly from the reference soil, and resulted in approximately similar levels of bulk density, porosity, air permeability and specific permeability as the tractor with high drawbar pull. Still, the deformation was stronger for the single pass of the tractor with the high drawbar pull than for six repeated wheeling of the passive trailer wheel. These results highlight the substantial effect of traction on soil compaction. Yet, the mechanisms causing this deformation remain speculative until the propagation of horizontal stress through the soil profile is better understood.

FEATURES OF ADAPTIVE BRAKE CONTROL OF THE SECONDARY BRAKE SYSTEM OF A MULTI-AXLE VEHICLE

Problem. A malfunction of the service braking system of a wheeled vehicle (CTS) significantly affects road safety, especially when operating multi-axle vehicles with large masses. One of the ways to increase the level of road safety of multi-axle vehicles, when braking them using a spare (emergency) braking system, is the introduction of automated adaptive braking systems into the design of the brake drive of vehicles. The definition of the limits of the use of the adaptive braking system on vehicles with many axles is almost not disclosed in the scientific and technical literature, therefore, the issue of using such a system on vehicles with a large number of axles requires additional research. Purpose. The purpose of this work is to develop a simulation model for adaptive control of the braking process of a multi-axle vehicle using a spare (emergency) braking system, taking into account the simulation of the dynamics of the drive and the variability of the adhesion properties between the tire of the vehicle wheel and the road surface. Methodology. To achieve this goal, it is necessary to develop a simulation model of the brake drive in an adaptive mode, implement a model of the interaction of the tire with the road surface, and implement a model of the braking dynamics of a multi-axle vehicle in the event of a malfunction of its service brake system. Originality. The proposed key criterion (Kr) for changing the throttle section in electro-pneumatic pressure modulators, which provide adaptive air inlet or outlet from the corresponding brake chambers of the drive, during simulation, made it possible to simulate the operation of the drive circuits in the adaptive mode. It has been established that, depending on the potential for the realization of the adhesion between the tires of automobile wheels and the road surface, the pressure in the electro-pneumatic brake drive with its adaptive regulation can be increased by no more than 0.04 MPa.