Traction Performance Research Articles

Towards a real-time pneumatic tire performance prediction using an advanced tire-ice interface model

Icy road conditions and tire operational parameters play a vital role in determining the overall performance of a vehicle. This study builds on prior work in the researchers’ group. The Advanced Tire-Ice Interface Model (ATIIM) simulates the temperature rise in the contact patch based on the measured pressure distribution and the thermal properties of the tread compound and of the ice surface. It has the capability to simulate the height of the thin water film created from the melted ice, to predict the tractive performance, and to estimate the viscous friction due to the water layer and the influence of braking operations, including the locked wheel condition. The experimental investigation included measuring the bulk temperature distribution in the contact patch to validate the temperature rise simulations of the ATIIM. As shown by the simulations and the test data, a rise in temperature was observed from the leading edge to the trailing edge of the contact patch. As the wheel load increases, the difference in temperature rise increases, as also reflected in the experimental study. When the temperature difference was significant, a thin water film was observed that resulted in a reduction of friction, which was simulated using the ATIIM.

Adaptive localization and mapping with application to planetary rovers

AbstractFuture exploration rovers will be equipped with substantial onboard autonomy. SLAM is a fundamental part and has a close connection with robot perception, planning, and control. The community has made great progress in the past decade by enabling real‐world solutions and is addressing important challenges in high‐level scalability, resources awareness, and domain adaptation. A novel adaptive SLAM system is proposed to accomplish rover navigation and computational demands. It starts from a three‐dimensional odometry dead reckoning solution and builds up to a full graph optimization that takes into account rover traction performance. A complete kinematics of the rover locomotion system improves the wheel odometry solution. In addition, an odometry error model is inferred using Gaussian processes (GPs) to predict nonsystematic errors induced by poor traction of the rover with the terrain. The nonparametric GP regression serves to adapt the localization and mapping to the current navigation demands (domain adaptation). The method brings scalability and adaptiveness to modern SLAM. Therefore, an adaptive strategy develops to adjust the image frame rate (active perception) and to influence the optimization backend by including high informative keyframes in the graph (adaptive information gain). The work is experimentally verified on a representative planetary rover under a realistic field test scenario. The results show a modern SLAM systems that adapt to the predicted error. The system maintains accuracy with less number of nodes taking the most benefit of both wheel and visual methods in a consistent graph‐based smoothing approach.

Performance of a special tractor as a function of ballasting and front-wheel drive in coffee harvesting

One of the main concerns before agricultural mechanization is the fuel cost from an economic and environmental point of view. In some literature, it has been demonstrated that the adequacy of tractors is directly related to consumption, which may become a strategy to reduce it. However, the studies were performed with conventional tractors, without information on how the special coffee tractors behave to the adequacy. In this respect, the aim of the present study was to evaluate the hourly fuel consumption in six possible adjustments of a special tractor in the operation of mechanized coffee harvesting. A 4x2 FWD tractor was used, with 52.2 kW power and 2400 kg mass, with 40% to the front axle and 60% to the rear to pull a Master Café 2 coffee harvester with 2900 kg mass without load. The treatments consisted of three ballast configurations in the tractor whether or not using auxiliary front-wheel drive (FWD). The adopted mass-power ratios were: 48, 52 and 56 kg kW<em>-1</em>; obtained through the quantitative alteration of liquid and solid ballasts of the tractor, respecting the mass distribution between the axles recommended by the tractor manufacturer. The evaluations consisted of monitoring fuel consumption at regular hourly intervals, following the premises of statistical process control. It is concluded that the mass-power ratio of 56 kg kW<em>-1</em> with driven FWD should be used in order to obtain lower slipping, lower average hourly fuel consumption and higher quality.

An adaptive sliding mode control to stabilize wheel slip and improve traction performance

Advanced antislip control methods are available these days. However, due to increasing requirements with regard to demand and emerging technologies in the field of railways, further research on antislip control is required. Therefore, in this study, an antislip control algorithm, based on a sliding mode control, is proposed to stabilize the slip and improve the traction ability of a full-scale tram wheel test stand. To verify the validity of the control scheme, a numerical model of a tram wheel test stand has been generated using the MATLAB editor. The Freibauer and Polach contact theory has been employed to determine the coefficient of adhesion and adhesion force. Moreover, the derived algorithm was implemented on a full-scale tram wheel test stand. Experiments were carried out under several wheel–roller surface conditions. The results of the refined numerical model are in good agreement with the experimental data obtained from the tram wheel test stand. For both the experimental tests and the numerical model, the response of the proposed control algorithm is rather satisfactory with regard to the stabilization of the slip and improvement of the traction ability.

CONJUNTO PARA AVALIAÇÃO DINÂMICA DO DESEMPENHO DE TRATORES AGRÍCOLAS

Determinar o desempenho operacional de máquinas agrícolas ocasionalmente torna-se uma tarefa difícil, devido às variações de carga ao longo do trajeto. Este trabalho teve como objetivo desenvolver e avaliar um carro dinamométrico preparado para mensurar o desempenho de tratores agrícolas em diferentes condições operacionais. O conjunto foi instrumentado com célula de carga, sensor magnético e fluxômetro capazes de monitorar a força disponível na barra de tração, o número de voltas dos rodados do trator e o consumo de combustível, respectivamente. Foram montados três experimentos: o primeiro para avaliação do processo de frenagem do carro dinamométrico; o segundo para avaliar o processo de aquisição automatizado do número de voltas dos rodados do trator e o terceiro para avaliação do consumo de combustível. Os processos foram examinados por meio de análise de variância, teste de médias e, quanto à estabilidade, por meio de cartas de controle de processos. O equipamento desenvolvido para avaliação dinâmica de tratores mostrou-se capaz de impor cargas à barra de tração do trator e fazer a coleta dos dados para os ensaios com precisão. A força imposta à barra e o consumo de combustível alcançaram valores médios esperados. A adaptação de um sensor magnético para monitorar o número de voltas das rodas mostrou-se eficaz, não havendo diferença das voltas quanto às contadas visualmente e automaticamente.

Estimation of the traction power of agricultural tractors from dynamometric tests

ABSTRACT: The objective of this research was to predict, from dynamometric tests, the traction performance of agricultural tractors, without the need to employ the standard official tests carried out on concrete tracks. The evaluations were conducted at the experimental area of the Universidade Federal de Santa Maria, where an instrumented agricultural tractor was subjected to dynamic field traction tests and static tests in the laboratory, using an eddy currents dynamometer. It can be verified through the correlation analysis between the values obtained and the estimated values that, based on the prediction equations, a high correlation (r² = 0.99) was obtained between the power observed in the field and the estimated power obtained using dynamometric tests. Based on the analysis of the results obtained in this study, it can be stated that the traction performance of an agricultural tractor can be estimated from dynamometric tests. We concluded that the dynamic field tests can be replaced by static tests carried out in laboratories, which are generally less expensive.

MODERN TENDENCIES OF AGRICULTURAL TRACTORS

It is noted that the main components of the quantitative evaluation of the performance of tractors are the indicators of their energy saturation and universality. The key characteristic of tractors of agricultural purpose is the traction class, which characterizes, first of all, the energy saturation of a tractor. Universality of agricultural tractors is characterized, mainly, by their maximum speeds of movement and average speeds of performance of transport works. It has been established that the most important directions for the development of the design of agricultural tractors are based on increasing their productivity. Increasing productivity is achieved by increasing both energy saturation and versatility, which allows to increase the time of continuous operation and the coefficient of using the tractor. It is determined that the increase in energy saturation is ensured by increasing the power of the power unit of wheeled tractors to 600 hp, as well as the addition of model series with new-level caterpillar tractors, closely aligned with wheel-type models of similar power. At the same time, the leading manufacturers of tractors are performing research and development in the development of the concept of an agricultural tractor with an engine of more than 500 hp. The increase in the universality of tractors is accompanied by the development of their construction, which ensures an increase in the maximum and average speeds of movement. The increase in transport speeds of up to 50–60 km/h and more is achieved by the improvement of stepped gearboxes, the development and introduction of continuously variable transmissions, the use and improvement of the characteristics of the suspension of the front driving axles, the cabin and the operator’s seat, the use of brakes of the front driving axle wheels, anti-lock and anti-traction systems, and all-wheel steering. It is shown that to increase the technical level of tractor equipment, great attention is paid to improving the operator’s working conditions, including by improving the design, improving the ergonomic and aesthetic properties of the cabins, automating work processes by developing and implementing on-board electronic control systems, diagnostics and controls. To reduce costs and increase the efficiency of agricultural production, the use of precision farming systems is becoming increasingly widespread.

Generalizability of Footwear Traction Performance across Flooring and Contaminant Conditions

OCCUPATIONAL APPLICATIONSThis study investigates the correlations between available coefficients-of-friction (ACOF) of 17 work shoes across different flooring and contaminant conditions. Five floorings (two vinyl tiles and three quarry tiles) were tested with water, sodium laurel sulfate, and canola oil. Shoe ACOF performance on a single quarry surface with any of the three contaminants was generally applicable to all other quarry-contaminant conditions. Shoe ACOF performance for a vinyl tile was generally applicable to another vinyl flooring for the same contaminant. These findings are anticipated to reduce the need for redundant shoe ACOF testing and clarify the generalizability of traction testing results.

Study on High Efficiency Permanent Magnet Linear Synchronous Motor for Maglev

This paper discusses the traction performance of a single-side linear induction motor and a single-side coreless Halbach permanent magnet linear synchronous motor (PM-LSM) for the mid- and low-speed maglev train. Based on a typical mid- and low-speed maglev transit system, the overall performance of the two kinds of propulsion motors was analyzed by the finite element method. By comparing the performance of the single-side coreless Halbach PM-LSM at different magnetization direction of the PMs of the Halbach array, the optimal angle between the magnetization direction of two adjacent PMs was found. In order to achieve the higher propulsion efficiency of the single-side coreless Halbach PM-LSM, various cross-sectional shapes of the conductor were analyzed. The analytical results indicate that the coreless Halbach PM-LSM is more suitable for the mid- and low-speed maglev train in urban rail transit system.

Evaluation of the impact on track of different locomotive running gear architectures

The paper compares two different locomotive architectures in order to evaluate their performances in terms of impact on the track. The reference locomotive is the three-axle bogie locomotive GT46ACe, used in the Australian and North American network, while the second one is a new concept locomotive with BoBoBo wheel arrangement and derived by an existing Italian locomotive, namely E.646. In order to make the comparison possible, the existing Italian locomotive has an increased axle-load and adapted suspensions in order to make its traction performances comparable with the ones of the reference locomotive. The two vehicles have been tested on different tracks and considering different traction levels. The preliminary results show that the BoBoBo wheel arrangement could introduce several benefits with respect to the CoCo one in terms of track load reduction, wear and rolling contact fatigue.

Design and analysis of a compliant variable-diameter mechanism used in variable-diameter wheels for lunar rover

Variable-diameter wheels have two limited working statuses: the unfolded limit rimless wheel and the folded rigid circular wheel. These can solve the contradiction between tractive performance and the limited spacecraft volume of the lunar rover. The variable-diameter mechanism proposed here is the most critical part. It allows the wheel to transform its structure using expansion-retraction motion and to possess excellent running performance. A novel compliant mechanism configuration with helical torsion springs is introduced, along with its mechanism principles. Based on two extreme wheel statuses, a two-position motion generation using nonlinear optimization synthesis is used to determine the dimensional parameters of the mechanism. The load-deflection behavior is derived by developing a pseudo-rigid-body model for the mechanism. Load-deflection relationships obtained from the pseudo-rigid-body model are compared with the results of finite element analysis (FEA) simulations. The results show that the predictions made by the pseudo-rigid-body model (PRBM) are in good agreement. Overall, the design and analysis approaches proposed here are applicable for variable-diameter mechanisms. In addition, the load-deflection relationships presented can provide theoretical references for the variable control of the wheel diameter.

Experimental study of a tracked mobile robot’s mobility performance

This paper proposes an experimental method of predicting the traction performance of a small tracked mobile robot. Firstly, a track-terrain interaction model based on terramechanics is built. Then, an experimental platform of the tracked robot is established, on which the measurement methods of the parameters that influencing the accuracy of the prediction model are introduced and the data post-processing are improved, including drawbar pull, slip ratio, sinkage, track deformation and so on. Based on the experimental data, several key terrain parameters are identified. With the tracked robot platform, the drawbar pull-slip ratio relationship is tested, and the effects on drawbar pull considering different kinds of terrain and the influence of the grousers are analyzed as well. The research results provide a reference for the experimental study on the traction performance of small tracked robots.

Effect of variations in front wheels driving lead on performance of a farm tractor with mechanical front-wheel-drive

Most previous researches indicate that about 20–55% of available tractor power is lost in the process of interaction between tires and soil surface. Vertical wheel loads and tire performance are parameters that play a significant role in controlling slip and fuel consumption of a tractor. Tractor’s slip is adjusted by attaching additional weights and/or reducing tire pressures, and this may have an impact on driving lead of front wheels. Mechanical Front-Wheel-Drive (MFWD) tractors work efficiently when driving lead of front wheels is 3–4% in soft soil and 1–2% in hard soil. This research was aimed to experimentally determine such tire pressures that allow adjusting tractor’s slip without deviating from set value of driving lead of front wheels. The research was also aimed to determine the effect of driving lead of front wheels on MFWD tractor’s slip and fuel consumption. Experimental results showed that front/rear tire pressure combinations that generate a well-targeted driving lead of front wheels have no effect on slip on hard soil; however, it significantly affect fuel consumption. Results show that when air pressures in front/rear tires varied within 80–220 kPa, driving lead of front wheels varied in the range from +7.25% to −0.5%.

Tarım Traktörlerinde Kullanılan Klima Sistemlerinin Traktör Verimi ve Özgül Yakıt Tüketimine Etkileri

In this study, the effects of air-conditioning system on tractor performance and specific fuel consumption were examined and evaluated by experimental data. Loading performed from tractor power take-off in periodically by electrical dynamometer. Fuel consumption were measured in air-conditioning off and air-conditioning on usage and comments were discussed according to these values. In same speed and loading, measured specific fuel consumption value when the air conditioning is on more than measured specific fuel consumption value when the air conditioning is off. Torque values were measured and fuel power and power take-off power were calculated, these values were compared, comments were discussed according to these values. In same speed and loading, measured power take-off efficiency values when the air conditioning is on less than measured power take-off efficiency values when the air conditioning is off. This change is determined respectively as average 4.37%, 4.34% and 8.63% negatively for the measured three brand tractors. As a result of all data, the positive effect of air-conditioning usage on specific fuel consumption, the negative effect of air-conditioning usage on power take-off efficiency were determined.

Assessment of Factors Influencing the Performance of Agricultural Tractors: In the Case of Srikakulam City, A.P., India

Having attained the firm footing into the technological revolutions in the agriculture sector, it is evident that the usage of tractors for several purposes by majority group is highly appreciated for the productivity matters the difference. It was found imperative that the performance of tractors in line with efficiency, longevity, reparability, maintenance, comfort etc is considered to be the most influencing element which are depended on three major variables proposed are farmers’ Control factors, manufacturers’ control and drivers’ demographics. With the stated objective, a survey research backed up with quantitative and descriptive research design as well as cross sectional technique for data collection was adopted. The determined sample of 182 managerial, technical and administrative staff of all tractor showrooms in Srikakulam form the population frame of 334 was targeted. The ANOVA through SPSS 20 to test the formulated hypotheses was used and thereby the interpretation along with findings on the influence of the factors on the performance of tractors have been drawn, the recommendations in line with statistical inferences have also been disseminated to the related communities.

Method for calculating walking tractor performance considering operator's energy consumption

AnnotationThe paper proposes a method for calculating the performance of a walking tractor considering the operator’s energy consumption in the dynamics of the tractor movement. The study presents the results of a man's energy consumption determined during physical load. The work has established that the performance of the walking tractor directly depends on the value of operator’s physical action on the cultivator movement. The increase of the operator’s physical effort decreases the performance of the walking tractor, since the operator has to increase the rest time for rejuvenation. The authors have suggested a method for walking tractor performance calculation considering operator’s physical capabilities and his involvement into the tractor operation.

Influence of biodiesel on the performances of farm tractors: Experimental testing in stationary and non-stationary conditions

Abstract This paper demonstrates the results of testing the performance of tractors using fossil diesel, biodiesel, and blends of biodiesel and fossil diesel. The results of tests conducted in stationary and non-stationary conditions indicate that, in contrast to fossil diesel, the use of biodiesel and blends of biodiesel and fossil diesel reduce the power of engine and drawbar power, and increase specific fuel consumption. Thermal efficiency slightly improves with biodiesel blends. The differences become notable with bigger share of biodiesel in the blend. However, the changes are less notable regarding the differences in heating value, which is the result of complete combustion. Use of different fuels, compared to use of fossil diesel only, reduces the CO emission and temperature of exhaust fumes, and increases the CO2 emission and NOx. At maximum load, the difference between the parameters measured in stationary and non-stationary conditions is minimal. On the other hand, at lower loads, the load variable formed in non-stationary conditions of testing becomes noticeable which results in greater differences. However, decrease in engine power and increase in fuel consumption using biodiesel significantly deteriorated the exploitation characteristics of plowing tractors (production efficiency was reduced by 12.87% and fuel consumption per unit of cultivated area was increased by up to 21.63%).

OPERATING PERFORMANCE OF A TRACTOR WORKING WITH DIFFERENT RATIOS OF CASTOR BEAN AND JATROPHA BIODIESEL

There is a growing global quest for clean energy. One of the alternatives is the use of agroenergy, which is the use of vegetable and animal raw material for the production of biofuels. Among them, biodiesel stands out for its renewable and biodegradable nature. The objective of this study was to evaluate the operating performance and smoke opacity of an agricultural tractor fed with different types and ratios of castor bean and Jatropha biodiesels. The study was conducted at Fazenda Experimental CEUNES / UFES, Campus São Mateus - ES. The mixture ratios of biodiesel/diesel used were: B0 (0/100%), B5 (5% 95%), B15 (15%/85% diesel), B25 (25%/75%), B50 (50%/50%), B75 (75%/25%), and B100 (100%/0%). The results showed an increase of 20.0% and 14.8% in the specifc consumption comparing B0 to B100 of castor and Jatropha, respectively. The smoke opacity reduced 24.50% and 54.05% when working with castor and Jatropha biodiesel, respectively. The smoke opacity of the castor B100 is 65.68% higher when compared to Jatropha B100.

Objekterkennung und Positionsbestimmung in der Landwirtschaft am Beispiel eines Ankoppelassistenten

The increasing performance of modern tractors increases the demands on the operator. In order to further support the operator, the development of new assistance systems is necessary. For this reason, the Institute of Mobile Machines and Commercial Vehicles (IMN) at the Technische Universitat Braunschweig is conducting research into assistance systems based on optical sensors that increase ease of use, quality of work and safety. These assistance systems are being investigated in a publicly funded research project together with AGCO Fendt as an associated partner.

Improving the tractive performance of walking tractors using rubber tracks

The pneumatic wheels of a walking tractor were replaced with rubber track system to improve draught. Performance was evaluated in agricultural soils and compared with that when fitted with wheels. Tests were carried out in sandy clay loam soil with cone index (CI) varying from 250 to 1000 kPa for both the tractors. Data of motion resistance, pull and slip were acquired using different sensors and data acquisition system. For CI of 250, 500 and 1000 kPa, the observed motion resistance values for tracks were found to be 1012, 775 and 620 N, respectively, which represent 18.75%, 14.36% and 11.5% of the weight of the tested walking tractor and 935, 675 and 530 N for the wheeled walking tractor which represents 17.32%, 12.5% and 9.8% of its weight, respectively. Rubber tracked walking tractor developed greater drawbar pull than the wheeled one in all soil conditions. The drawbar pull developed with tracks is 115.2%, 75.9% and 62.4% more than that developed by comparable walking tractor fitted with standard wheels, respectively in soils with CI 250, 500 and 1000 kPa. Tractive efficiency (TE) of walking tractors fitted with rubber tracks was higher in all soil conditions. Also, tracks reached peak TE at higher net traction ratio (NTR) and maintained higher TE for a wider range of NTR. Wheels reached maximum TE at lower values of NTR, which drops off at higher NTR values. The results indicate a significant improvement in the tractive ability of walking tractor.