Experimental verification using a driving simulator of the effect of simultaneous optimal distribution of tyre forces for active vehicle handling control

Author(s):  
O Mokhiamar ◽  
M Abe

Both theoretical and experimental studies are carried out in order to prove the effect of the simultaneous optimum distribution of lateral and longitudinal tyre forces on enhancement of vehicle handling and stability assuming that all four wheels can be independently steered and driven/braked. A driving simulator is used as an experimental instrument to investigate the effect of the optimum tyre force distribution control. The inputs to the optimization process are the driver's commands (steering wheel angle and foot brake pressure/accelerator pedal pressure), while the outputs are lateral and longitudinal forces on all four wheels. Lateral and longitudinal tyre forces cannot be chosen arbitrarily, but must satisfy certain specified equality constraints. The equality constraints are related to the required total longitudinal force, total lateral force and total yaw moment to achieve a given vehicle motion. The total lateral force and total moment required are introduced using the model responses of side-slip angle and yaw rate to the driver's steering input, while the total longitudinal force is computed according to the driver's command (traction/braking). The results of either computer simulation or a driving simulator show that the influence of the proposed optimum tyre force distribution control on vehicle performance enhancement is significantly apparent. Furthermore, driving simulator results show very good agreement with the computer simulation results presented.

2004 ◽  
Vol 126 (4) ◽  
pp. 753-763 ◽  
Author(s):  
Ossama Mokhiamar ◽  
Masato Abe

This paper presents a proposed optimum tire force distribution method in order to optimize tire usage and find out how the tires should share longitudinal and lateral forces to achieve a target vehicle response under the assumption that all four wheels can be independently steered, driven, and braked. The inputs to the optimization process are the driver’s commands (steering wheel angle, accelerator pedal pressure, and foot brake pressure), while the outputs are lateral and longitudinal forces on all four wheels. Lateral and longitudinal tire forces cannot be chosen arbitrarily, they have to satisfy certain specified equality constraints. The equality constraints are related to the required total longitudinal force, total lateral force, and total yaw moment. The total lateral force and total moment required are introduced using the model responses of side-slip angle and yaw rate while the total longitudinal force is computed according to driver’s command (traction or braking). A computer simulation of a closed-loop driver-vehicle system subjected to evasive lane change with braking is used to prove the significant effects of the proposed optimal tire force distribution method on improving the limit handling performance. The robustness of the vehicle motion with the proposed control against the coefficient of friction variation as well as the effect of steering wheel angle amplitude is discussed.


2021 ◽  
Author(s):  
Junning Zhang ◽  
Shaopu YANG ◽  
Yongjie LU

Abstract In the study of vehicle dynamics, the accurate description of tire mechanical characteristics is the basis and key of vehicle dynamics simulation. An innovative tire model is proposed based on fuzzy algorithm and a sinusoidal membership function is used to design fuzzy rules. In order to ensure the accuracy of tire behavior calculation, this model is driven by a small amount of experimental data of tire mechanical characteristics. This tire model consists of four layers of fuzzy systems, each of which has a knowledge base. The data in knowledge base I is obtained by experiments, and the data of knowledge base II is computed by the upper system, and so is the later system. Then, the input signal, the change rate of side slip angle and slip rate, is considered to improve the calculation accuracy of the model. The proposed fuzzy tire model can accurately predict the longitudinal force, lateral force and self-aligning torque of the tire under unknown conditions. Finally, by comparing the fuzzy tire model with the experimental data, it is found that the maximum RRMSE (Relative Root Mean Square Error) value is not more than 0.14. It is proved that the model can accurately describe the tire
mechanical characteristics under combined conditions.


Author(s):  
Tamer Wasfy ◽  
Hatem Wasfy ◽  
Paramsothy Jayakumar ◽  
Srinivas Sanikommu

Abstract The objective of this study is to validate a high-fidelity finite element tire model on hard pavement. In this model, the tire rubber matrix is modeled using locking-free brick elements with embedded thin beam elements along the tire’s circumference, meridian, and diagonals for modeling the tire’s reinforcements (belt, ply and bead). The internal air pressure is applied as a distributed force on the inner surface of the brick elements. Frictional contact between the outer surface of the brick elements and the pavement is modeled using the penalty method along with an asperity based Coulomb friction model. In order to validate the tire model, a medium duty truck tire is modeled and the following response quantities are compared to experimental results: (1) normal load versus deflection at different tire pressures; (2) rolling resistance versus speed; (3) longitudinal force versus slip; (4) lateral force versus slip angle for different normal loads; and (5) self-aligning torque versus slip angle for different normal loads.


2014 ◽  
Vol 945-949 ◽  
pp. 53-60
Author(s):  
Xiao Long Zhang ◽  
Rong Guo

Accurate full vehicle handling prediction can be used to evaluate the vehicle dynamic performance. This paper presents the prediction and correlation of full vehicle handling with ADAMS/Car. After building the initial model, major flexible component, steering friction and damping was introduced to optimize the model that makes the model much more accurate. The model will be used to run four major vehicle handling events; the predicted results are compared with measured data. The correlation includes time history of steering wheel angle, steering torque, lateral acceleration, side slip angle, roll, yaw etc. It also includes the derivates such as understeer gradients, steering gradients, side slip gradients, roll gradients etc. It is shown that good correlations are obtained in handling;


Author(s):  
B Mashadi ◽  
D A Crolla

A vehicle model was developed for the investigation of the influence of ride motions on handling dynamics of passenger vehicles. The inputs to the vehicle model are the steering wheel angle and a road profile at each wheel. The outputs were first compared with the results of independent handling and ride models, and good agreement was shown to exist. The combined motion of the vehicle was investigated by the application of step steering wheel angle inputs while travelling on a rough road surface. It was seen that the cornering ability at low and moderate levels of lateral acceleration on the roads with moderate roughness was similar to that on the smooth road, but larger body side-slip angles and tyre slip angles occurred over the rough road surfaces for similar steering inputs. The maximum achievable lateral acceleration was reduced on roads with moderate roughness owing to the earlier saturation of tyre slip angles compared with those on smooth roads. Over very rough roads and at high lateral accelerations, because of the large fluctuations of normal loads and the rapid drop in available lateral force, the body side-slip angle dramatically increased, which led to instability characterized by the oversteering behaviour. At high lateral accelerations close to the limit, the vehicle that understeered over the smooth road surface exhibited oversteering behaviour over rough road surfaces.


Robotica ◽  
2019 ◽  
Vol 37 (9) ◽  
pp. 1545-1561 ◽  
Author(s):  
Pablo Menendez-Aponte ◽  
Xiangling Kong ◽  
Yunjun Xu

SummaryRecently, autonomous field robots have been investigated as a labor-reducing means to scout through commercial strawberry fields for disease detection or fruit harvesting. To achieve accurate over-bed and cross-bed motions, it is preferred to design the motion controller based on a precise dynamic model. Here, a dynamic model is developed for a custom-designed strawberry field robot considering terramechanic wheel–terrain interaction. Different from existing models, a torus geometry is considered for the wheels. In order to obtain a control affine model, the longitudinal force is curve-fitted using a polynomial function of the slip/skid ratio, while the lateral force is curve-fitted using an exponential function of both the slip/skid ratio and slip angle. An extended Kalman filter (EKF) is then developed to estimate the unknown parameters in the approximated model such that the state variables propagated by such a model can match experimental data. The approximated model and the EKF-based parameter estimation method are then validated in a commercial strawberry farm.


2005 ◽  
Vol 33 (1) ◽  
pp. 18-37 ◽  
Author(s):  
B. G. Kao ◽  
T. Warholic

Abstract The Bushing Analogy Tire (BAT) model has been studied for tire dynamics modeling in vertical and lateral directions. It was shown that the vibration characteristics included in the BAT model in the vertical and lateral directions cover the tire modes in those directions up to about 100 Hz. This capability of the BAT model is suitable for vehicle ride simulations. However, in vehicle handling situations such as accident avoidance, the tire is subjected to sudden steering motions that are not included in the vertical and lateral dynamics. The steering generates tire slip angle and, hence, the lateral forces for vehicle direction change. The tire steering motion also generates the aligning torque, which modifies the slip angle of the tire with respect to the wheel input steering angle. The tire steering compliance is therefore important for the dynamic responses during the vehicle handling maneuvers. In this paper, tire compliance in the steering direction is studied by treating the steering motion as an independent motion of the 3-dimentional tires. In this paper, the steering stiffness (or compliance) of a tire is first derived from the analysis results of a tire Finite Element (FE) model. Comparing the steering direction vibration modes using the BAT model with the FE model extracted modes further validates the steering stiffness. The coupling of tire steering stiffness with the vertical forces is also studied. Then, the effects of the tire steering direction stiffness are used to study a data set of flat-track generated tire lateral force and moment. The procedure of generating required coefficients of a handling tire model coupled with tire dynamic features of the BAT model were also investigated.


2020 ◽  
Vol 10 (22) ◽  
pp. 8072
Author(s):  
Seong Han Kim ◽  
Min Chul Shin

When a vehicle goes on the straight road with a bank angle, a steering pull makes the driver exert a constant steering torque to the steering wheel, which causes an annoying steering feel to the driver. This paper proposes a steering pull model and sensitivity analysis on the steering pull. In order to develop the steering pull model, pulling forces on the tires, such as plysteer and conicity forces, lateral force due to slip angle, lifting forces due to cast and kingpin, and camber force are modeled. A steering system is also modeled because the generated pulling forces are attenuated as it is transmitted through the steering system. Each component of the steering system, such as lower body linkages, rack and pinion gear, universal joint, and steering column with electric power steering (EPS) system is modeled, and then they are integrated into a complete steering system. Finally, the steering pull model is developed by integrating the pulling force model with the steering system model. For verification, the steering pull of a vehicle is estimated based on the model, and the results are compared with the experimental results. For the verification experiments, a steering pull measurement system using a global positioning system (GPS) and its accessories are used. The result comparison showed that the developed steering pull model provides very accurate estimation results. Based on the steering pull model, the sensitivity of steering pull factors, such as caster angle, kingpin angle, camber angle, rack friction force, and anti-rattle spring (ARS) stiffness is analyzed.


1989 ◽  
Vol 17 (2) ◽  
pp. 86-99 ◽  
Author(s):  
I. Gardner ◽  
M. Theves

Abstract During a cornering maneuver by a vehicle, high forces are exerted on the tire's footprint and in the contact zone between the tire and the rim. To optimize the design of these components, a method is presented whereby the forces at the tire-rim interface and between the tire and roadway may be predicted using finite element analysis. The cornering tire is modeled quasi-statically using a nonlinear geometric approach, with a lateral force and a slip angle applied to the spindle of the wheel to simulate the cornering loads. These values were obtained experimentally from a force and moment machine. This procedure avoids the need for a costly dynamic analysis. Good agreement was obtained with experimental results for self-aligning torque, giving confidence in the results obtained in the tire footprint and at the rim. The model allows prediction of the geometry and of the pressure distributions in the footprint, since friction and slip effects in this area were considered. The model lends itself to further refinement for improved accuracy and additional applications.


1993 ◽  
Vol 21 (2) ◽  
pp. 91-119 ◽  
Author(s):  
H. S. Radt ◽  
D. A. Glemming

Abstract Semi-empirical theories of tire mechanics are employed to determine appropriate means to normalize forces, moments, angles, and slip ratios. Force and moment measurements on a P195/70R 14 tire were normalized to show that data at different loads could then be superimposed, yielding close to one normalized curve. Included are lateral force, self-aligning torque, and overturning moment as a function of slip angle, inclination angle, slip ratio, and combinations. It is shown that, by proper normalization of the data, one need only determine one normalized force function that applies to combinations of slip angle, camber angle, and load or slip angle, slip ratio, and load. Normalized curves are compared for the effects of inflation pressure and surface water thickness. Potential benefits as well as limitations and deficiencies of the approach are presented.


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