Maximum automobile acceleration

Problem. The disadvantage of current dependences for determining the acceleration indicators at engine maximum brake power and driving tire-to-surface friction coefficients is that they are adequate only if the engine and transmission parameters provide power input to the drive wheels rolling without slipping regardless to speed. To eliminate this drawback, it is necessary to take into account that the power input to the drive wheels depends on the engine shaft speed, and therefore on the speed of the vehicle when accelerating. Goal. The purpose of the work is to further develop the theory of the automobile by improving the dependencies that allow determining the automobile acceleration rates and assessing the nature of its acceleration process from the design factors. Methodology. The approaches taken to achieve this goal are based on laws of physics, theoretical mechanics and the theory of automobile. Results. Analytic dependences for determining maximum and limiting automobile acceleration when speeding up depending on its design factors and speed have been improved. Dependences for determining the range of drive wheel slipping on the automobile speed when accelerating and the limiting automobile acceleration under the condition of its pitch stability have been obtained. When studying the automobile acceleration process theoretically it was found that the developed dependences allow determining the nature of automobile movement and assessing the influence of its design factors on the acceleration indicators. Originality. The obtained dependences for determining the maximum and limiting acceleration, the range of driving speeds with wheel slip when automobile accelerating allowed us to clarify the idea of the nature of movement during acceleration and the influence of automobile design factors on the acceleration indicators. Practical value. The obtained dependences can be used in designing new and improving racing cars such as dragsters, and analysing the dynamics of the vehicle when accelerating with full fuel delivery and determining the nature of driving tire-to-surface friction depending on the driving speed.

Torque Vectoring Control of RWID Electric Vehicle for Reducing Driving-Wheel Slippage Energy Dissipation in Cornering

The anxiety of driving range and inconvenience of battery recharging has placed high requirements on the energy efficiency of electric vehicles. To reduce driving-wheel slip energy consumption while cornering, a torque vectoring control strategy for a rear-wheel independent-drive (RWID) electric vehicle is proposed. First, the longitudinal linear stiffness of each driving wheel is estimated by using the approach of recursive least squares. Then, an initial differential torque is calculated for reducing their overall tire slippage energy dissipation. However, before the differential torque is applied to the two side of driving wheels, an acceleration slip regulation (ASR) is introduced into the overall control strategy to avoid entering into the tire adhesion saturation region resulting in excessive slip. Finally, the simulations of typical manoeuvring conditions are performed to verify the veracity of the estimated tire longitudinal linear stiffness and effectiveness of the torque vectoring control strategy. As a result, the proposed torque vectoring control leads to the largest reduction of around 17% slip power consumption for the situations carried out above.

Technical performance evaluation of a double row tractor operated yam minisett planter

Uniformity in plant spacing, evenness of dropping, planter capacity and among others has been identified as constraints facing planter performance. The main objective of the study was to evaluate the technical performance of the developed double row yam minisett (DRYM) planter. Category (I) tractor 50 hp was used to carry out field trials to determine the metering efficiency, effective field capacity, evenness of dropping, fuel consumption and wheel slippage. Three (3) yam varieties (pona, dente and CRI afase biri) of the average weight of 50 g with moisture content (82 %) were used for the test. Multivariate and (ANOVA) statistical method was used for analyzing the similarities among the tractor speed using OriginPro 2018 software. Metering efficiency (80.4%), effective field capacity (3.84 h/ha), field efficiency (66.6%), evenness of dropping (81.00%), and wheel slip (3.39%) were recorded. The use of developed planter will be expected to reduce human drudgery and also timeliness improvement. The study concluded that planter should be used on relatively flat (ploughed-harrowed) land to avoid wheel not touching the ground.

Modeling and analysis of motion with wheel slip of the mobile platform with four wheel drive

The problem of motion with wheel slip of the four wheeled mobile platform has been discussed in this work. Considering the model of dynamics, the formulation of the initial problem of the platform motion and the numerical algorithm for solving this problem has been presented. The Runge-Kutta 4th order method has been used to integrate the equations of motion. Possible cases of motion of the prototype of the mobile platform with four drive modules have been considered. Taking into account the variable values of the active forces caused by the drive torque and changes in the position of the wheels during the platform motion, as well as the resistant forces opposing the active forces at the contact points of the wheels with the ground, the platform motion simulation results have been obtained. Different wheel settings, with controlling the active forces and directions of their settings while driving have been implemented to the model. The results of motion simulations and their analysis have been included. The results presented in the paper show a significant influence of wheel slip on the parameters of the motion of the mobile platform. The computational model presented in the paper enables a good representation of the platform motion parameters, which has been confirmed by comparing the results of simulation tests with the results of experimental tests of motion in relation to a construction solution of the platform other than described in the paper. Further development of the computational model is planned, mainly in order to include the deformability of the wheel suspension systems in the dynamic model of the platform, which will allow for the implementation of wider studies of the motion of such objects, including, for example, in the case of wheels passing through obstacles.

Functional and performance test of modified lug wheel on two wheels tractor with pivot type trailer

Palm oil fields with slopes require special wheels for transportation for transporting fresh fruit bunches (FFB), the special wheels in question are modified wheels from the existing cage wheel, the modified wheels can adjust the slope conditions on the land with the lug angle adjustment mechanism. The objective of this study was to test the functional and performance of the modified lug wheel as a means of transporting FFB on sloping land using a hand tractor on a pivot type trailer. Functional testing on the modified lug wheel was carried out by observing changes in the angle of the lugs (0, 15, 30, 45)0 by lifting one of the tractor shafts first using a jack, after which the locking pins were released. The angle change rim can be moved clockwise or anticlockwise by hand according to the desired lug angle. Performance testing on the modified lug wheel is carried out by observing and calculating the slip on the wheel. Functional testing on trailer pivots is carried out by observing all components of the towing system when installed and operated, to determine whether the trailer towing system can function properly. Performance testing on the pivot trailer is done by observing and calculating the turning radius when the tractor turns. Performance testing is also carried out by observing the stability of the two-wheel tractor and trailer. The slope of the land and the angle of the lugs greatly affect wheel slip, the higher the slope on a land, the higher the possibility of wheel slippage during operation. The test results show that the use of modified lug wheels shows better performance at 30° lug angle, as seen from the smaller slip value at 30° lug angle.