Road Load Analysis

2003 ◽  
Vol 31 (1) ◽  
pp. 19-38 ◽  
Author(s):  
M. Sobhanie

Abstract Severe loading in a tire/suspension system arises when a rolling tire impacts an obstacle, such as a curb or pothole. Forces and moments at suspension hard points are needed during an impact for component specification, component durability, and endurance analysis. Today, automotive manufacturers and suppliers are promoting virtual prototyping by use of a computer-aided engineering (CAE) tool. CAE consists of a tire model, a suspension model, and a solver for equilibrium equations. The tire models can be classified either by a parametric tire model (PTM) or by a finite element tire model. In the former tire model, tire stiffness is represented by a set of springs; tire forces and moments are estimated by Pajeka equations. This class of tire models is limited to modeling a vehicle's performance, such as ride and handling. In recent years, explicit dynamic modeling of a rolling tire impacting a road imperfection has been used to calculate forces transmitted to a suspension system. The tire model consisted of a single layer of shell elements; solid elements were considered for the tread cap. The beads were not considered in this tire model. In this analysis, ABAQUS Explicit was used to model the rolling and transient impact of a tire. ABAQUS Explicit's modeling results were compared to ABAQUS Standard's results. The comparison included the tire forces, footprint pressure distribution at a free rolling condition, and resonant frequencies. In addition, modeling results of a tire/suspension system traversing an obstacle were presented. The suspension components, except spring and shock, were modeled by rigid elements connected together.

2010 ◽  
Vol 38 (3) ◽  
pp. 228-244 ◽  
Author(s):  
Nenggen Ding ◽  
Saied Taheri

Abstract Easy-to-use tire models for vehicle dynamics have been persistently studied for such applications as control design and model-based on-line estimation. This paper proposes a modified combined-slip tire model based on Dugoff tire. The proposed model takes emphasis on less time consumption for calculation and uses a minimum set of parameters to express tire forces. Modification of Dugoff tire model is made on two aspects: one is taking different tire/road friction coefficients for different magnitudes of slip and the other is employing the concept of friction ellipse. The proposed model is evaluated by comparison with the LuGre tire model. Although there are some discrepancies between the two models, the proposed combined-slip model is generally acceptable due to its simplicity and easiness to use. Extracting parameters from the coefficients of a Magic Formula tire model based on measured tire data, the proposed model is further evaluated by conducting a double lane change maneuver, and simulation results show that the trajectory using the proposed tire model is closer to that using the Magic Formula tire model than Dugoff tire model.


2019 ◽  
Vol 47 (3) ◽  
pp. 211-231
Author(s):  
Anton Albinsson ◽  
Fredrik Bruzelius ◽  
P. Schalk Els ◽  
Bengt Jacobson ◽  
Egbert Bakker

ABSTRACT Vehicle-based tire testing can potentially make it easier to reparametrize tire models for different road surfaces. A passenger car equipped with external sensors was used to measure all input and output signals of the standard tire interface during a ramp steer maneuver at constant velocity. In these measurements, large lateral force vibrations are observed for slip angles above the lateral peak force with clear peaks in the frequency spectrum of the signal at 50 Hz and at multiples of this frequency. These vibrations can lower the average lateral force generated by the tires, and it is therefore important to understand which external factors influence these vibrations. Hence, when using tire models that do not capture these effects, the operating conditions during the testing are important for the accuracy of the tire model in a given maneuver. An Ftire model parameterization of tires used in vehicle-based tire testing is used to investigate these vibrations. A simple suspension model is used together with the tire model to conceptually model the effects of the suspension on the vibrations. The sensitivity of these vibrations to different operating conditions is also investigated together with the influence of the testing procedure and testing equipment (i.e., vehicle and sensors) on the lateral tire force vibrations. Note that the study does not attempt to explain the root cause of these vibrations. The simulation results show that these vibrations can lower the average lateral force generated by the tire for the same operating conditions. The results imply that it is important to consider the lateral tire force vibrations when parameterizing tire models, which does not model these vibrations. Furthermore, the vehicle suspension and operating conditions will change the amplitude of these vibrations and must therefore also be considered in maneuvers in which these vibrations occur.


2020 ◽  
Vol 2020 ◽  
pp. 1-16
Author(s):  
Guangzong Gao ◽  
Jixin Wang ◽  
Tao Ma ◽  
Wenzhong Liu ◽  
Tianlong Lei

The distributed drive articulated steering vehicle (DDASV) has a broad application prospect in the field of special operations. It is essential to obtain accurate vehicle states for better effect of active control. DDASV dynamic model is presented. To improve robustness, an adaptive strong tracking algorithm is applied to the singular value decomposition unscented Kalman filter (SVDUKF). Divided by yaw rate sensors and the tire models, two multistage estimators are established for DDASVs. Stable steering condition is simulated to investigate the influence on the estimated accuracy about the sensors and tire models. The velocities and tire forces are the key parameters to be estimated. The performance of each estimator regarding the practicability and accuracy is compared. The results show that all estimators are practicable. However, the accuracy of the estimated velocities based on yaw rate sensors is better and the transient tire model can improve the accuracy of estimated lateral forces more effectively for the estimator established with yaw rate sensors.


2002 ◽  
Vol 30 (3) ◽  
pp. 136-155 ◽  
Author(s):  
B. G. Kao

Abstract Tire radial stiffness is traditionally calculated from the wheel load deflection measurement. Statically, this stiffness serves to provide the support for the vehicle. However, this stiffness does not provide sufficient understanding of how the tire behaves dynamically: the tire first radial modes, no matter how they were measured, cannot be correlated with this statically measured stiffness. A comprehensive explanation for this phenomenon is needed for better understanding of tire dynamics and hence building the dynamic tire models. In this paper, the relationship between the tire static stiffness and the tire radial vibration modes is investigated using the bushing analogy tire (BAT) modeling concept. It is found that the tire first radial mode, though it can be of different values through different measuring methods, can be explained consistently with this model. A procedure to obtain consistent tire stiffness for the tire model is also proposed as a result of this investigation.


2019 ◽  
Vol 47 (2) ◽  
pp. 118-140
Author(s):  
Artem Kusachov ◽  
Fredrik Bruzelius ◽  
Mattias Hjort ◽  
Bengt J. H. Jacobson

ABSTRACT Commonly used tire models for vehicle-handling simulations are derived from the assumption of a flat and solid surface. Snow surfaces are nonsolid and may move under the tire. This results in inaccurate tire models and simulation results that are too far from the true phenomena. This article describes a physically motivated tire model that takes the effect of snow shearing into account. The brush tire model approach is used to describe an additional interaction between the packed snow in tire tread pattern voids with the snow road surface. Fewer parameters and low complexity make it suitable for real-time applications. The presented model is compared with test track tire measurements from a large set of different tires. Results suggest higher accuracy compared with conventional tire models. Moreover, the model is also proven to be capable of correctly predicting the self-aligning torque given the force characteristics.


1977 ◽  
Vol 5 (2) ◽  
pp. 75-82 ◽  
Author(s):  
A. Schallamach

Abstract Expressions are derived for side force and self-aligning torque of a simple tire model on wet roads with velocity-dependent friction. The results agree qualitatively with experimental results at moderate speeds. In particular, the theory correctly predicts that the self-aligning torque can become negative under easily realizable circumstances. The slip angle at which the torque reverses sign should increase with the normal load.


2015 ◽  
Vol 75 (8) ◽  
Author(s):  
N. Ikhsan ◽  
R. Ramli ◽  
A. Alias

In this paper, the optimum setting for suspension hard points was determined from a half vehicle suspension system. These optimized values were obtained by considering the Kinematic and Compliance (K&C) effects of a verified PROTON WRM 44 P0-34 suspension model developed using MSC/ADAMS/CAR. For optimization process, multi body dynamic software, MSC/ADAMS/INSIGHT and Design of Experiment (DoE) method was employed. There were total of 60 hard points (factors) in x, y and z axis-direction for both front and rear suspension while toe, camber and caster change were selected as the objective function (responses) to be minimized. The values of 5 mm, 10 mm and 15 mm were used as relative values of factor setting to determine the factor range during optimization process. The hard point axis-direction that has the most effects on the responses was identified using the Pareto chart to optimize while the rests were eliminated. As expected result, a new set of suspension system model with a selected of Kinematic and Compliance (K&C) data set were obtained, and compared with the verified simulation data when subjected to the vertical parallel movement simulation test to determine the best setting and optimum suspension hard points configuration.  


Author(s):  
Amirhossein Kazemipour ◽  
Alireza B Novinzadeh

In this paper, a control system is designed for a vehicle active suspension system. In particular, a novel terminal sliding-mode-based fault-tolerant control strategy is presented for the control problem of a nonlinear quarter-car suspension model in the presence of model uncertainties, unknown external disturbances, and actuator failures. The adaptation algorithms are introduced to obviate the need for prior information of the bounds of faults in actuators and uncertainties in the model of the active suspension system. The finite-time convergence of the closed-loop system trajectories is proved by Lyapunov's stability theorem under the suggested control method. Finally, detailed simulations are presented to demonstrate the efficacy and implementation of the developed control strategy.


2012 ◽  
Vol 479-481 ◽  
pp. 1355-1360
Author(s):  
Jian Guo Chen ◽  
Jun Sheng Cheng ◽  
Yong Hong Nie

Vehicle suspension is a MIMO coupling nonlinear system; its vibration couples that of the tires. When magneto-rheological dampers are adopted to attenuate vibration of the sprung mass, the damping forces of the dampers need to be distributed. For the suspension without decoupling, the vibration attenuation is difficult to be controlled precisely. In order to attenuate the vibration of the vehicle effectively, a nonlinear full vehicle semi-active suspension model is proposed. Considering the realization of the control of magneto-rheological dampers, a hysteretic polynomial damper model is adopted. A differential geometry approach is used to decouple the nonlinear suspension system, so that the wheels and sprung mass become independent linear subsystems and independent to each other. A control rule of vibration attenuation is designed, by which the control current applied to the magneto-rheological damper is calculated, and used for the decoupled suspension system. The simulations show that the acceleration of the sprung mass is attenuated greatly, which indicates that the control algorithm is effective and the hysteretic polynomial damper model is practicable.


Author(s):  
P. Khan ◽  
P. Hwang

The 4-DOF suspension model is employed in order to analyze the multiple flying height states of the coupled air bearing – suspension system. The results are compared with previously presented results for the simpler suspension model.


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