Optimization of the tractive performance of four-wheel-drive tractors: Theoretical analysis and experimental substantiation

1998 ◽  
Vol 212 (4) ◽  
pp. 285-297 ◽  
Author(s):  
J. Y. Wong ◽  
N. B. McLaughlin ◽  
Z Knezevic ◽  
S Burtt
Keyword(s):  
Theoretical Analysis ◽  
Field Test ◽  
Angular Speed ◽  
Speed Ratio ◽  
Torque Distribution ◽  
Wheel Drive ◽  
Four Wheel Drive ◽  
Tractive Efficiency ◽  
Driving Torque ◽  
Experimental Substantiation

The results of a theoretical analysis reveal that, for a four-wheel-drive tractor to achieve the optimum tractive performance under a given operating condition, the thrust (or driving torque) distribution between the front and rear axles should be such that the slips of the front and rear tyres are equal. For four-wheel-drive tractors with rigidly coupled front and rear drive axles, this can be achieved if the theoretical speed (the product of the angular speed and the free-rolling radius of the tyre) of the front and that of the rear wheels are equal or the theoretical speed ratio is equal to 1. Field test data confirm the theoretical findings that, when the theoretical speed ratio is equal to 1, the efficiency of slip and tractive efficiency reach their respective peaks, the fuel consumption per unit drawbar power reaches a minimum, and the overall tractive performance is at an optimum.

Tractive efficiency of four-wheel-drive vehicles: An analysis for non-uniform traction conditions

2003 ◽  
Vol 217 (5) ◽  
pp. 363-374 ◽  
Author(s):  
B C Besselink
Keyword(s):  
Mathematical Analysis ◽  
Fixed Ratio ◽  
Graphical Analysis ◽  
The Other ◽  
Speed Ratio ◽  
Road Vehicles ◽  
Wheel Drive ◽  
Four Wheel Drive ◽  
Tractive Efficiency ◽  
Rigorous Mathematical Analysis

An analysis of the tractive efficiency of four-wheel-drive vehicles is conducted from the perspective of maximizing efficiency of slip with respect to non-uniform traction conditions in particular. The analysis is conducted using a more rigorous mathematical analysis than previously and using a thorough graphical analysis to substantiate the mathematical analysis. Previous studies concluded that under all traction conditions efficiency of slip will be a maximum when the slip of each wheel is equal. The analysis revealed that, contrary to the previous literature, efficiency of slip will not be a maximum when the slip of each wheel is equal under non-uniform traction conditions. When applied to a vehicle with an interaxle fixed ratio coupling, this means that the optimum theoretical speed ratio is not always equal to 1. An example of non-uniform traction conditions is the situation where two drive wheels are on soil and the other two are on tarmac. The improvement in the efficiency of slip, in this example, when using the correct theoretical speed ratio (as opposed to that equal to 1) is particularly marked at high drawbar loads. The method by which the correct theoretical speed ratio is to be achieved when non-uniform traction conditions occur is problematic. The drive system would require a drive mechanism and a level of intelligence not currently found in off-road vehicles.

Adaptive equivalent consumption minimisation strategy and dynamic control allocation-based optimal power management strategy for four-wheel drive hybrid electric vehicles

2018 ◽  
Vol 233 (12) ◽  
pp. 3125-3146 ◽  
Author(s):  
Hui Liu ◽  
Xunming Li ◽  
Weida Wang ◽  
Lijin Han ◽  
Huibin Xin ◽  
...  
Keyword(s):  
Power Management ◽  
Management Strategy ◽  
Dynamic Control ◽  
Control Allocation ◽  
Energy Management Strategy ◽  
Torque Distribution ◽  
Power Management Strategy ◽  
Optimal Power ◽  
Wheel Drive ◽  
Four Wheel Drive

An adaptive equivalent consumption minimisation strategy and dynamic control allocation-based optimal power management strategy for a four-wheel drive plug-in hybrid electric vehicle is proposed in this paper. The equivalent factors of adaptive equivalent consumption minimisation strategy are optimised offline based on ISIGHT software over several typical driving cycles, which is integrated with AVL CRUISE and MATLAB/Simulink. To update the equivalent factor adaptively according to the predictive velocity, a neural network-based optimal equivalent factor prediction model is built, which can be used online. The torque distribution strategy considering axle load based on energy management strategy optimisation results and the vehicle dynamics control distribution is proposed: this includes two-wheel drive torque distribution, four-wheel drive torque distribution and brake torque distribution. The proposed energy management strategy is verified in New European Driving Cycle and Worldwide harmonised Light Vehicle Test Cycle driving patterns, and the simulation results show that the fuel economy of adaptive equivalent consumption minimisation strategy and dynamic control allocation-based optimal power management strategy is improved by 8.84% and 7.52% in New European Driving Cycle and Worldwide harmonised Light Vehicle Test Cycle, respectively, compared with the benchmark algorithm-based strategy.

Propulsion Dynamic Requirements Analysis for Multi-Axle Skid-Steer Wheeled Vehicles

2020 ◽  
Author(s):  
Mostafa Yacoub ◽  
Ahmed Ali
Keyword(s):  
Experimental Validation ◽  
Worst Case ◽  
Wheeled Vehicle ◽  
Wheel Drive ◽  
System Requirements ◽  
Turning Radius ◽  
Four Wheel Drive ◽  
Driving Torque ◽  
Wheeled Vehicles ◽  
Selection Of

Abstract Multi-axle skid-steer wheeled vehicles have the advantages of simplicity and enhanced traction. That’s why they are used in off-road environments and also in mobile robots. In the present work, a dynamic analysis of the propulsion system requirements for multi-axle wheeled vehicles is investigated. As the multi-axle wheeled vehicle differentially steers at a smaller turning radius, the driving torque requirements approach their peak. The adhesion at each tire of the multi-axle vehicle and its relation to the contact patches are analyzed. The analysis presented starts with four wheel drive, six wheel drive and eight wheel drive vehicles, then it is widened to n-wheel drive vehicles. A generic formula for obtaining the propulsion torque requirements for multi-axle skid-steer wheeled vehicles is presented. The analysis is extended to include experimental validation of the obtained analytical results. The experimental work includes three small electrically driven skid-steer vehicles; four wheel drive vehicle, six wheel drive vehicle and eight wheel drive vehicle. The selection of the drive motors for each of those vehicles was based on the proposed formula. Each of the three vehicles was tested in the worst case adhesion torque requirement. The experimental results showed that the proposed formula is capable, to a great extent, to predict the torque requirements for the multi-axle skid-steer wheeled vehicles in the design phase.

Torque Distribution Strategy for Multi-PMSM Applications and Optimal Acceleration Control for Four-Wheel-Drive Electric Vehicles

2019 ◽  
Vol 142 (2) ◽  
Author(s):  
Ziyou Song ◽  
Heath Hofmann ◽  
Jianqiu Li ◽  
Yuanying Wang ◽  
Dongbin Lu ◽  
...  
Keyword(s):  
Electric Vehicles ◽  
Optimization Problems ◽  
Maximum Efficiency ◽  
Programming Approach ◽  
Acceleration Process ◽  
Torque Distribution ◽  
Distribution Strategy ◽  
Wheel Drive ◽  
Wide Range ◽  
Four Wheel Drive

Abstract In this paper, a general torque distribution strategy is proposed to improve the drivetrain efficiency of four-wheel-drive electric vehicles (EVs). The strategy allows the same or different motors to be equipped in the front and rear wheels. The model of the drivetrain considers the loss properties of four permanent magnet synchronous motors (PMSMs) and four inverters over a wide range of torque and speed. The relationship between the drivetrain efficiency and the torque split ratio at any given speed is proven to be convex under both traction and regenerative braking conditions. It is shown that, when all four motors are identical, the maximum efficiency can be achieved if the total torque is equally shared. An equivalent loss strategy, which is a general method and can solve many optimization problems of multi-PMSM applications, is proposed to maximize the drivetrain efficiency when different PMSMs are used in the front and rear wheels. The effectiveness of the proposed strategy is verified using an urban dynamometer driving schedule (UDDS). In addition, the acceleration process of EVs is optimized using a dynamic programming approach to minimize acceleration duration and energy consumption. Simulation results show that, with the proposed strategy, the energy loss during the acceleration can be reduced by up to 15%.

scholarly journals Study on the Control of Torque Distribution of 4WD Corn Harvester Operation Drive

2021 ◽  
Vol 11 (19) ◽  
pp. 9152
Author(s):  
Deyi Zhou ◽  
Pengfei Hou ◽  
Yuelin Xin ◽  
Xinlei Lv ◽  
Baoguang Wu ◽  
...  
Keyword(s):  
Reference Value ◽  
Operating Conditions ◽  
Torque Control ◽  
Agricultural Machinery ◽  
Torque Distribution ◽  
Drive Torque ◽  
Adjustment Time ◽  
Wheel Drive ◽  
Four Wheel Drive ◽  
Passing Ability

In response to the poor adaptability of existing harvesters to complex operating conditions in the field, this study took a three-row four-wheel-drive (4WD) corn harvester as the research object, designed a traveling transmission system layout, proposed a control strategy of driving torque distribution, simulated, and analyzed each of the four states of harvester drive wheels slippage. The results showed that under the driving wheels slipping condition, after applying torque control, the adjustment time was 43.3% shorter than that without control in the case of single wheel slipping, 11.1% shorter than that without control in the case of two wheels slipping on the same axle, 41.4% shorter than that without control in the case of two wheels slipping on different axles, and 36.6% shorter than that without control in the case of three driving wheels slipping. The application of drive torque distribution control could significantly improve the traction and passing ability of the corn harvesters during operation, as well as made the harvester travel more smoothly, thus improving the harvest quality. The drive torque distribution control can be applied not only to the three-row corn harvester, but also to other types of harvesters, and self-propelled agricultural machinery to enhance their adaptability, improving their operation quality. It has a significant reference value for the development of the driving system on walking agricultural machinery.

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