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The maneuvering time on the ground accounts for 10%–30% of their flight time, and it always exceeds 50% for short-haul aircraft when the ground traffic is congested. Aircraft also contribute significantly to emissions, fuel burn, and noise when taxiing on the ground at airports. There is an urgent need to reduce aircraft taxiing time on the ground. However, it is too expensive for airports and aircraft carriers to build and maintain more runways, and it is space-limited to tow the aircraft fast using tractors. Autonomous drive capability is currently the best solution for aircraft, which can save the maneuver time for aircraft. An idea is proposed that the wheels are driven by APU-powered (auxiliary power unit) motors, APU is working on its efficient point; consequently, the emissions, fuel burn, and noise will be reduced significantly. For Front-wheel drive aircraft, the front wheel must provide longitudinal force to tow the plane forward and lateral force to help the aircraft make a turn. Forward traction effects the aircraft’s maximum turning ability, which is difficult to be modeled to guide the controller design. Deep reinforcement learning provides a powerful tool to help us design controllers for black-box models; however, the models of related works are always simplified, fixed, or not easily modified, but that is what we care about most. Only with complex models can the trained controller be intelligent. High-fidelity models that can easily modified are necessary for aircraft ground maneuver controller design. This paper focuses on the maneuvering problem of front-wheel drive aircraft, a high-fidelity aircraft taxiing dynamic model is established, including the 6-DOF airframe, landing gears, and nonlinear tire force model. A deep reinforcement learning based controller was designed to improve the maneuver performance of front-wheel drive aircraft. It is proved that in some conditions, the DRL based controller outperformed conventional look-ahead controllers.

In this paper, we propose a model for eco-driving that considers cornering effects. The proposed model purely relies on the geometric configuration of the vehicle and road. Consequently, we propose an eco-driving optimal control problem formulation that is suitable for both straight and curved trajectories in urban scenarios. Moreover, it can be applied for vehicles with front wheel drive (FWD) or rear wheel drive (RWD). We use a case study for an electric vehicle executing cornering maneuvers to validate the proposed approach and highlight its advantages with respect to traditional eco-driving formulations. Results show an approximated improvement of 8% in energy savings with respect to traditional eco-driving strategies, especially in trajectories with large curvatures.

This paper proposes a calculator for estimation of drawbar pull supplied by mechanical front wheel drive tractor based on nominal input variable of tractor driving mode in two-wheel drive (2WD) and four-wheel drive (4WD), and numeral input variables of tractor weight (53.04–78.45 kN) and slip of driving wheels (1.4–15.1%) utilizing intelligent fuzzy systems. The systems were developed by means of various input membership functions, output membership functions, defuzzification methods, and training cycles. The prominent developed system for estimation of the drawbar pull yielded a user-friendly intelligent fuzzy calculator with admissible accuracy (coefficient of determination = 0.993). Data obtained from the calculator revealed increasing nonlinear trend of the drawbar pull in range of 12.9–57.5 kN as concurrent augment of slip of the wheels and tractor weight, for 2WD mode. In case of the 4WD mode, it nonlinearly raised from 12.8 to 77.7 kN. Therefore, effect of the slip and weight on the drawbar pull was found synergetic. Moreover, the drawbar pull ranges elucidated that the drawbar pull proliferated as the 4WD mode was employed rather than the 2WD mode. Generally, benchmark of the prominent developed intelligent fuzzy system, not only provide simple calculator with the widest applicability for different tractor models, but also produces added values in enrichment of realization level in domain of tractor drawbar pull concepts.

Modern motorcycles are evolving more and more towards complex systems by the increasing integration of mechanical, electrical and control disciplines. All-wheel drive (AWD) vehicles have proven effective to improve vehicle's performances and rider's safety. Despite this, manufacturers have developed few AWD motorcycles and little research has been devoted to them. Obvious difficulties concern torque distribution to the front wheel because of steering system. Nowadays, the integration of technologies eases the implementation of front wheel drive opening new research perspectives. In this work, the dynamic model of an AWD motorcycle with an attached rider is proposed. It represents the first symbolic analysis investigating the effects of front wheel traction on the dynamics of a motorcycle for supporting the design of AWD motorcycles reducing trials and tests on prototypes. The proposed model is parametric with respect to the motorcycle geometry, and it allows to simulate complex operating modes of the AWD, such as cornering phenomena, taking into account coupling of lateral and longitudinal dynamics and tire-road interactions. Unlike other works, here the authors include a full tire model by exploiting theoretical slips of the brush model for tire's aligning moment too, instead of applying a totally empirical representation less suitable for a complete symbolic description. Besides, to simulate the equations of motion, the benefits and disadvantages of using AWD with torque distribution have been pointed out introducing a new handling ratio. Two verification procedures validate the model: one is performed theoretically, the other carries out a comparison with a multibody software, whose model is more sophisticated, this latter embeds all main motorcycle's dynamics. Although radically different, being the first theoretical and the second numerical-computational, both methods exhibit consistent behavior between them, and effectiveness of the former is also consistent with the results of a multibody simulator under the assumptions made.

Energy recovery by means of braking with the electric machine helps to extend the cruising range of electric vehicles. By optimising the recuperation system, the total energy efficiency is increased. In general, using a usual brake force distribution the capability for recuperation is not equal for every type of drive train. Usually, four-wheel drives are advantageous in comparison to drive trains with only one driven axle. Regarding the single drives, generally, a front-wheel drive provides a higher capability for recuperation than a rear-wheel drive. This is mainly due to the dynamic axle load shift, which occurs during decelerations. In order to increase the energy recovery of electric vehicles with single drive, an adaptive brake force distribution is presented and compared with other brake force distributions in this study. It uses the knowledge of the currently available adhesion coefficient between tyre and road. The positive effect on the recuperation without impairing the braking performance on a straight road is demonstrated based on simulations. In curves, the lateral forces additionally need to be considered to guarantee the stability of the vehicle, especially relating to electric vehicles having a rear-wheel drive.

In this study the lateral control of an automated vehicle is analysed with the help of a single-track model while subject to a hierarchical control algorithm. At the higher-level we command the steering angle based on the vehicle’s relative position and orientation to the desired path, while the lower-level controller tries to achieve this angle by adjusting the steering torque. The stability of the straight-line motion is investigated by incorporating time delays at both control levels. We demonstrate that the two control algorithms can be designed independently from each other. Moreover, we show that the stability of the lower-level controller is highly sensitive to the delay, that is, to ensure stability very high sampling frequency is required.

A potência disponível na barra de tração e na tomada de potência juntamente com a reserva de torque são algumas das principais características a serem analisadas nos tratores agrícolas. Neste sentido, conduziu-se o presente trabalho com o objetivo de avaliar os parâmetros relacionados à potência e ao torque dos tratores agrícolas de pneus comercializados no Brasil em relação a quatro faixas de potência e tipo de tração. O trabalho foi realizado por meio de levantamento das informações em 191 tratores agrícolas, sendo estas obtidas nos catálogos dos espécimes e em alguns casos medidos em loco, quando a informação não estava presente no catálogo. Os parâmetros de potência disponível na tomada de potência e na barra de tração e a reserva de torque foram estimados; sendo que alguns desses parâmetros foram avaliados em diferentes condições de solo. Os dados foram analisados utilizando-se ferramentas da estatística descritiva para comparação dos espécimes. Os tratores superpesados com tração dianteira auxiliar apresentam maior torque disponível na potência nominal do motor, na TDP a 540 rpm e reserva de torque. Os espécimes da faixa de potência média e tração 4x2 TDA têm maior representatividade no mercado nacional, correspondendo a 47 e 79%, respectivamente.

Estimulada por políticas acessíveis de crédito agrícola e busca de melhores condições de trabalho, a agricultura familiar brasileira vem passando por constantes transformações no que diz respeito à utilização de máquinas agrícolas. Nesse cenário, o trator agrícola esta cada vez mais presente, portanto, conhecer o custo de manutenção dessa importante fonte de potência é estratégico para a sustentabilidade econômica das unidades de produção familiares. Devido a esta realidade, objetivou-se com este trabalho determinar os custos relativos a manutenção devido a troca de filtros, lubrificantes e pneus de tratores agrícolas com potência no motor de até 72,9 kW, subdivididos em tipo de tração e categoria do sistema hidráulico. Para a realização deste trabalho foram coletados dados técnicos, preços dos lubrificantes e materiais de substituição periódica. As variáveis quantitativas e qualitativas foram: especificações técnicas - marca, modelo, potência máxima no motor, designação dos pneus, duração e quantidade trocada de filtros, lubrificantes e pneus. Foram analisados 94 modelos, 25 com tração nas duas rodas motrizes e 69 com tração dianteira auxiliar (TDA). Concluiu-se que menores custos médios de manutenção são obtidos em tratores 4x2 e categoria I no sistema hidráulico e maiores custos médios de manutenção são obtidos em tratores 4x2 TDA e categoria II no sistema hidráulico. Os coeficientes de variação encontrados foram altos entre os modelos estudados com custos mínimos e máximos de respectivamente R$ 0,82 e R$ 5,73 (R$ h-1).

Made available in DSpace on 2018-12-11T17:33:40Z (GMT). No. of bitstreams: 0 Previous issue date: 2017-01-01. Added 1 bitstream(s) on 2021-07-15T14:34:16Z : No. of bitstreams: 1 S0100-69162017000400699.pdf: 481340 bytes, checksum: fd53e16da4807f0f0bc4764d0035d989 (MD5) The mechanized gathering process of sweeping coffee is extremely important to reduce the losses of fruit not used in the harvesting operation. But this operation usually has a low operational performance and a high cost per unit collected in this way any measures that can effectively reduce costs increase the viability of the operation. In this sense, studies on adequacy tractor mass for each operation show improvement in energy use, reducing fuel consumption. So, this study aimed to quantify the fuel consumption and effective power along the process of a tractor 4x2 FWD pulling the coffee harvester. I was used as treatments three ballasting settings, these being equivalent the relations power to weight of 36, 39 and 42 kg hp-1 working with and without activated FWD, randomized statistically, with 10 repetitions each configuration. It was conclude that, at low power-weight ratio, the front wheel drive assist had no significant influence on the hour fuel consumption. Already in the configuration with higher ratio, the use of front wheel drive favored in reducing fuel consumption and better energy use. São Paulo State University (Unesp) School of Agricultural and Veterinarian Sciences Federal University of São Carlos São Paulo State University (Unesp) School of Agricultural and Veterinarian Sciences

The development of alternative vehicle were continued by designing hybrid vehicle that using compressed air and electrical propulsion. This compressed air propulsion on the rear wheels and two electric motor as a front wheel drive (FWD) were installed independently, where left and right can rotate with different speeds and direction. Independent FWD could be a problem when two wheels has a different rotation. The first experiment was tested by measuring the rotation per minute (RPM) on each wheel. Measurement were performed by varying the position of the throttle pedal. The result of measurements on both wheels rotating speed showed a difference of 1 %. The second test was to compare the space requirement, which derived from the function of cornering radius. Space requirement for inactive vehicle cornering system is 4.52 meters and 3.39 meters when system is active.

Modeling and control strategies for a design of an autonomous three wheeled mobile robot with front wheel steer is presented. Although, the three-wheel vehicle design with front wheel steer is common in automotive vehicles used often in public transport, but its advantages in navigation and localization of autonomous vehicles is seldom utilized. We present the system model for such a robotic vehicle. A PID controller for speed control is designed for the model obtained and has been implemented in a digital control framework. The trajectory control framework, which is a challenging task for such a three-wheeled robot has also been presented in the paper. The derived system model has been verified using experimental results obtained for the robot vehicle design. Controller performance and robustness issues have also been discussed briefly., Comment: IEEE International Conference on Robotic Computing 2017. (under review)

This article presents a new dynamic motion stabilization approach to front-wheel drive in-wheel motor electric vehicles. The approach includes functions such as traction control system, electronic differential system, and electronic stability control. The presented electric vehicle was endowed with anti-skid performance in longitudinal accelerated start; smooth turning with less tire scrubbing; and safe driving experience in two-dimensional steering. The analysis of the presented system is given in numerical derivations. For practical verifications, this article employed a hands-on electric vehicle named Corsa-electric vehicle to carry out the tests. The presented approach contains an integrated scheme which can achieve the mentioned functions in a single microprocessor. The experimental results demonstrated the effectiveness and feasibility of the presented methodology.

Tripod constant velocity joints are used in the driveshafts of front wheel drive vehicles. Thrust force generated by this joint causes lateral vibration in these vehicles. This paper surveys some methods for reducing the thrust force based on the mechanisms inducing the thrust force, focusing on a method that creates dual contact between a roller and groove. This method has the advantage of requiring only a few design modifications, but its thrust force reduction mechanism has yet to be clarified. Therefore, a theory was constructed to describe the induction of thrust force by this method through the application of sliding velocities generated between the roller and dual contact groove. Subsequently, the effect of the thrust force reduction was investigated. This paper also describes the appropriateness of this theory. It was validated by comparing theoretical results with computational results based on a multibody dynamics approach and with experimental results of a prototype joint equipped with the dual contact grooves.

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-1; 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-1 with driven FWD should be used in order to obtain lower slipping, lower average hourly fuel consumption and higher quality.

Most electric vehicles adopt cooperative braking systems that can blend friction braking torque with regenerative braking torque to achieve higher energy efficiency while maintaining a certain braking performance and driving safety. This paper presented a new cooperative regenerative braking system that contained a fully-decoupled hydraulic braking mechanism based on a modified electric stability control system. The pressure control algorithm and brake force distribution strategy were also discussed. Dynamic models of a front wheel drive electric car equipped with this system and a simulation platform with a driver model and driving cycles were established. Tests to evaluate the braking performance and energy regeneration were simulated and analyzed on this platform and the simulation results showed the feasibility and effectiveness of this system.

We propose an electronic differential system (EDS) based on a wavelet controller for electric vehicle with dual-wheeled-motor front drive. According to an analysis of current electronic differential strategies and vehicle driving dynamics, a new electronic differential strategy model of equal power allocation is proposed, and based on an analysis of the mathematical model of an interior permanent magnet synchronous motor, a new current controller based on the discrete wavelet transform is proposed using vector control. Based on A&D5435 hardware-in-the-loop simulation system and Carsim/Simulink, the test and simulation platform of the electric vehicle with dual-wheeled-motor front drive are established, and a vehicle performance simulation and test are performed under various driving conditions. The test and simulation results show that the equal power allocation EDS based on a wavelet controller for a front-wheel independent-drive electric vehicle proposed in this article shows excellent differential effects, stability, robustness, and vehicle handling stability.

Tripod constant velocity joints are used in the driveshaft of front wheel drive vehicles. Thrust force generated by this joint causes lateral vibration in these vehicles. To determine the mechanisms inducing the thrust force, a detailed model is constructed based on a multibody dynamics approach. Although the joint is equipped with three rollers and grooves, this model consists of the principal parts for one roller and groove in order to precisely analyze frictional phenomena occurring between the roller and the groove. These principal parts are defined as rigid bodies and are connected by force elements of contact and friction. The appropriateness of this model is verified by comparing computational and experimental results and it is clarified that the principal factors inducing the thrust force are three kinds of sliding friction force at the point of contact between the roller and the groove. This paper also describes the reason why the third rotating order component of the thrust force is induced by one roller and groove.

Idle gear rattle is associated with the characteristic noise that unselected impacting gears radiate to the environment. It is induced by engine order vibration in the presence of backlash in the unengaged gear pairs, resulting in oscillatory response within their backlash range. A tribo-dynamic model of a front wheel drive manual transmission has been developed to study idle rattle, considering the hydrodynamic contact film reaction and flank friction. The model includes the torsional motions of the idle gears and the lateral motions of the supporting output shafts. The hydrodynamic lubricant film formed between the gear teeth under light impact loads behaves as a nonlinear spring-damper mechanism, whilst the inclusion of the shafts’ bearing compliances introduces additional nonlinear terms, which are modelled as piecewise linear functions. The aim of the paper is to extend the existing methodology reported by the authors on idle rattle investigations of geared lubricated systems, based on torsional vibrations only, by considering the system response, which is eventually transferred to the gearbox case through the bearings. These are preliminary results found, which conform closely to experimental measurements taken from a vehicle equipped with a manual transmission of the same type.

The ball-fixed joint (BJ) is one of the fixed type constant-velocity-joint (CVJ), and it is widely used in front wheel drive systems of the car. For the recent needs of good mileage and lightweight for the car, the compact CVJ that reduced ball size and increased ball number is developed, and mass-produced. Meanwhile, there is a possibility that the solution of tribological subject of long life under high pressure bring more lightweight and compact design. Then the practical development of new grease is generally performed. But because of non-understanding about characteristics of contact surfaces, e.g. relative slip velocity or spin, the development is inefficient. On the other hand, the pole and the equator of the oil stain were sometimes observed on the balls after endurance test of BJ. The solution of the formation mechanism of the pole and the equator is one subject for understanding the characteristics of the contact surfaces. In this paper, the formation mechanism of the pole and the equator is investigated by measuring the rotational motion of the ball of BJ with the hall sensors in the endurance test, and by using dynamic analysis together.

Ball-type constant-velocity joints are extremely important components of the front wheel drive systems of cars. However the method to analyze the characteristics of this type of joints has not been established. The authors previously presented papers on the analysis based on statics, in that no frictional forces inside the joints were taken into account. Recently the authors presented advanced analysis based on dynamics, in which the frictional forces were considered. In this paper the numerical analyses of a ball fixed joint (BJ) and a double offset joint (DOJ) used for the front wheel drive of a car are carried out using the simultaneous equations induced in the former analysis and the simultaneous differential equations induced in the latter analysis. Contact forces acting inside DOJ are measured using piezo-electric sensors. The results of the numerical analyses based on dynamics show better coincidence with the measured value than those based on statics.

The choice of tractor configuration is of primary importance in tillage operations for the optimisation of traction performance, i.e. for limiting slip which involves energy loss. To a great extent, this aspect affects the fuel consumption and the time required for soil tillage. Tyre inflation pressure and wheel load are both easily managed parameters which play a significant role in controlling the traction performance of a tractor. The present study aimed to investigate the influence of tyre inflation pressure and wheel load on the traction performance of a mechanical front wheel drive MFWD tractor (65 kW engine power) on an agricultural clay (C) Vertic Cambisol on the basis of results of traction tests and simulations with a semi-empirical soil-tyre interaction model adapted for MFWD vehicles. The traction tests were carried out using four tractor configurations with two tractor weights (40.8 kN and 50.2 kN) and two tyre inflation pressures (60 kPa and 160 kPa). Traction performance was considered in terms of drawbar pull, traction coefficient, tractive efficiency, power delivery efficiency and specific fuel consumption in relation to wheel slip. A decrease in tyre pressure and an increase in wheel load resulted in higher drawbar pull however, only the former produced improvements in terms of coefficient of traction, tractive efficiency, power delivery efficiency and specific fuel consumption, while the only significant benefit resulting from the latter was a reduction in specific fuel consumption at a tyre pressure of 160 kPa and a slip of under 15%.

An analytical model to simulate the traction performance of mechanical front wheel drive MFWD tractors was developed at the Agroscope Reckenholz-Tänikon ART. The model was validated via several field tests in which the relationship between drawbar pull and slip was measured for four MFWD tractors of power ranging between 40 and 123 kW on four arable soils of different texture (clay, clay loam, silty loam, and loamy sand). The pulling tests were carried out in steady-state controlling the pulling force along numerous corridors. Different configurations of tractors were considered by changing the wheel load and the tyre pressure. Simulations of traction performance matched experimental results with good agreement (mean error of 8% with maximum and minimum values of 17% and 1% respectively). The model was used as framework for developing a new module for the excel application TASCV3.0.xlsm, a practical computer tool which compares different tractor configurations, soil textures and conditions, in order to determine variants which make for better traction performance, this resulting in saving fuel and time, i.e. reducing the costs of tillage management.

International audience; This paper introduces a new method to support designers to find optimal and robust solutions of engine mounting system. The mounting system design is a compromise between isolation of the vehicle from engine vibration and constraining the motion of the powertrain within vehicle packaging. Based on the classical pendulum mounting system of a front wheel drive vehicle with a transversely four-cylinder engine, this study deals with the definition of a new global engine mounting concept for the NVH (Noise Vibration and Harshness) improvement of the vehicle characteristics at idle speed. The practical application of the numerical optimization is complicated by the fact that engine mounting system is a stochastic system. Its characteristics have a probabilistic nature. Multi-Objective Genetic Algorithm (MOGA), i.e. Pareto-optimization, is taken as the appropriate framework for the definition and the solution of the addressed multi-objective robust optimization problem. An experimental correlation analysis has been conducted on a Pareto-optimal solution to show the model accuracy.

Forklift Trucks Are The Single Most Versatile Industrial Material-Handling Device. This Versatility Is Created By The Ability Of The Flt To Move Loads In Three Dimensions, I.E., Forward, Laterally, And Vertically. This Freedom Of Movement Is Provided By The Rear Steer Front Wheel Drive Configuration Of Flts Permitting The Flt To Move Loads Into Tight Spaces And Also By The Mast Permitting The Forks To Raise And Lower Loads For Stacking. As Part Of The Stacking Operation The Masts Of Flts Have The Capability Of Tilting Fore And Aft, Which Permits The Forks To Get Under The Load And Then Once Placed On The Forks, For The Load To Be Raised And Then Cradled By The Forks By Tilting The Mast Backwards...A Case Study Is Presented Of A Fatality Accident Involving A Large Capacity Flt (52,000 Pound Capacity) Carrying 11 Sheets Of Steel Which Were 10 x 20 x 1/4 Each Weighing Approximately 1500 Pounds. The Operator Of The Flt Set The Load At About 1416 Above The Ground, Set The Spotting Brake, And Exited The Cab To Rearrange A Number Of Wooden Spacers Upon Which He Intended To Place The Sheets Of Steel. The Mast Drifted, Causing The Forks To Angle Down, Which In Turn Permitted The Sheets Of Steel To Slide Off The Forks (Much Like A Deck Of Cards) And Strike The Worker (Previously The Operator), Resulting In His Death.

The optimum vehicle configuration and component locations are determined for an electric drive vehicle based on using the basic structure of a current production subcompact vehicle. The optimization of an electric vehicle layout requires a weight distribution in the range of 53/47 to 62/38 in order to assure dynamic handling characteristics comparable to current internal combustion engine vehicles. Necessary modification of the base vehicle can be accomplished without major modification of the structure or running gear. As long as batteries are as heavy and require as much space as they currently do, they must be divided into two packages, one at front under the hood and a second at the rear under the cargo area, in order to achieve the desired weight distribution. The weight distribution criteria requires the placement of batteries at the front of the vehicle even when the central tunnel is used for the location of some batteries. The optimum layout has a front motor and front wheel drive. This configuration provides the optimum vehicle dynamic handling characteristics and the maximum passenger and cargo space for a given size vehicle.