Wheel Speed Effect on Transient Lateral Force and Its Characterization by Ramp-Step Steer Test Method

2021 ◽  
Author(s):  
Yi Li
Keyword(s):  
Contact Point ◽  
Transient Behavior ◽  
Wheel Speed ◽  
Rolling Speed ◽  
Test Method ◽  
Slip Angle ◽  
Relaxation Length ◽  
Underlying Assumption ◽  
Lateral Response ◽  
Speed Effect

ABSTRACT The concept “relaxation length” serves as one of several ways to characterize the transient lateral response for a rolling tire. Most test methods developed to identify relaxation length tightly link to Pacejka's single-contact-point linear transient model. Its underlying assumption is that the traveled distance during the transition interval is always a constant regardless of the wheels' linear rolling speed. The current research provides physical data against this strong assumption. The data is acquired through a newly-developed test method named the “ramp-step steer method”. The ramp-step steer method features a nonstop, high rolling speed, and fast-changing slip angle procedure that cannot be fulfilled by the conventional “start-stop-resume” step steer method. Thanks to the high dynamic capability of the equipment in GCAPS Corp., the proposed test method becomes feasible. A novel data postprocessing scheme accompanies the test method as well. The ramp-step steer method is independent of any specific models and replicates the scenario of a rolling tire subjected to a sudden slip angle change from on-vehicle to an indoor environment. The wheel speed effect on the tires' transient lateral response is reflected through a proposed quantity, Ly, which is a more general descriptor and can downscale to relaxation length under specific circumstances. Ly itself does not associate with any model, so the remaining study explains the speed effect through an updated model. The present research aims to provide a better way of characterizing tires' lateral transient behavior and is not an alternative to identify the key parameter “relaxation length” in Pacejka's model. Another contribution of the research is categorizing and separating the hierarchy of various transient tire models.

A Fast and Reliable Dynamic Tyre-Road Contact Model for ABS Braking Manoeuvre Simulations

2006 ◽  
Author(s):  
Francesco Braghin ◽  
Federico Cheli ◽  
Emiliano Giangiulio ◽  
Federico Mancosu ◽  
Daniele Arosio
Keyword(s):  
Differential Equation ◽  
Steady State ◽  
Order Differential Equation ◽  
Transient Behavior ◽  
Slip Angle ◽  
Relaxation Length ◽  
Steady State Condition ◽  
Tyre Model ◽  
First Order ◽  
Significant Parameter

Due to the dimensions of the tyre-road contact area, transients in a tyre last approximately 0.1s. Thus, in the case of abrupt maneuvers such as ABS braking, the use of a steady-state tyre model to predict the vehicle’s behavior would lead to significant errors. Available dynamic tyre models, such as Pacejka’s MF-Tyre model, are based on steady-state formulations and the transient behavior of the tyre is included by introducing a first order differential equation of relevant quantities such as the slip angle and the slippage. In these differential equations the most significant parameter used to describe the transient behavior is the so-called relaxation length, i.e. the distance traveled by the tyre to settle to a new steady–state condition once perturbated. Usually this parameter is assumed to be constant.

A Dynamic Tire Model for ABS Maneuver Simulations

2010 ◽  
Vol 38 (2) ◽  
pp. 137-154 ◽  
Author(s):  
Francesco Braghin ◽  
Edoardo Sabbioni
Keyword(s):  
Steady State ◽  
Order Differential Equation ◽  
Transient Behavior ◽  
Slip Angle ◽  
Tire Model ◽  
Relaxation Length ◽  
Steady State Condition ◽  
First Order ◽  
Significant Parameter ◽  
Tire Models

Abstract Due to the dimensions of the tire-road contact area, transients in a tire last approximately 0.1 s. Thus, in the case of abrupt maneuvers such as ABS braking, the use of a steady-state tire model to predict the vehicle’s behavior would lead to significant errors. Available dynamic tire models, such as Pacejka’s MF-Tire model, are based on steady-state formulations and the transient behavior of the tire is included by introducing a first order differential equation of relevant quantities such as the slip angle and the slippage. In these differential equations the most significant parameter used to describe the transient behavior is the so-called relaxation length, i.e., the distance traveled by the tire to settle to a new steady-state condition once perturbated. Usually this parameter is assumed to be constant.

A Modal Approach for the Study of the Transient Behavior of Motorcycle and Scooter Tires

2014 ◽  
Author(s):  
Alberto Doria ◽  
Luca Taraborrelli ◽  
Marco Urbani
Keyword(s):  
Experimental Tests ◽  
Rotating Disk ◽  
Transient Behavior ◽  
Slip Angle ◽  
Phase Lag ◽  
Relaxation Length ◽  
Rigid Ring ◽  
Wide Range ◽  
Tire Forces ◽  
Wheeled Vehicles

Stability of two-wheeled vehicles is influenced by the transient properties of tires, which are described in terms of the relaxation length, which is the distance that the vehicle travels before tire forces reach the steady state values. Relaxation length is often studied by means of rigid ring models, in which the belt of the tire is modeled as a rigid ring elastically connected to the rim and the contact patch is connected to the belt by means of residual springs. Actually these models are able to take into account the lateral and the diametrical modes of vibration of the rigid belt with respect to the rim and to represent in a simplified way the modes with belt deformation by means of the residual stiffness. Experimental tests are needed to find the parameters of the models and to validate results. This research focuses on the relaxation length of side-slip force and aims to improve knowledge in this field, since there is no consolidated method for deriving the parameters of rigid ring models and, especially in two-wheeled vehicles, the relevance of rigid belt and deformable belt modes is not well known. Experimental tests are performed on a rotating disk machine developed for testing tires of two-wheeled vehicles, two motorcycle and two scooter tires are considered. Transient properties are studied by carrying out tests with harmonic variations of side-slip angle, since in the frequency domain the relaxation length corresponds to a phase lag between the input and tire force. Phase lags are measured and relaxation lengths are identified for a wide range of inflation pressures. Then each tire is modally tested and natural frequencies, dampings and vibration modes are found, the stiffnesses associated to the lateral and diametrical modes are identified. Finally a comparison is made between the identified relaxation length and the prediction given by a model based on the identified tire modes. The relevance of deformable belt modes is analyzed and their influence on relaxation length is discussed.

scholarly journals A Strain-Based Intelligent Tire to Detect Contact Patch Features for Complex Maneuvers

Sensors ◽  
2020 ◽  
Vol 20 (6) ◽  
pp. 1750 ◽  
Author(s):  
Mª Fernanda Mendoza-Petit ◽  
Daniel García-Pozuelo ◽  
Vicente Díaz ◽  
Oluremi Olatunbosun
Keyword(s):  
Fuzzy Logic ◽  
Contact Point ◽  
Contact Length ◽  
Fuzzy Logic System ◽  
Simulation Software ◽  
Slip Angle ◽  
Rolling Velocity ◽  
Contact Patch ◽  
Essential Components ◽  
Logic System

Tires are essential components of vehicles and are able to transmit traction and braking forces to the contact patch, contribute to directional stability, and also help to absorb shocks. If these components can provide information related to the tire–road interaction, vehicle safety can be increased. This research is focused on developing the tire as an active sensor capable to provide its functional parameters. Therefore, in this work, we studied strain-based measurements on the contact patch to develop an algorithm to compute the wheel velocity at the contact point, the effective rolling radius and the contact length on dynamic situations. These parameters directly influence the dynamics of wheel behavior which nowadays is not clearly defined. Herein, hypotheses have been assumed based on previous studies to develop the algorithm. The results expose to view an experimental test regarding influence of the tire operational condition (slip angle, vertical load, and rolling velocity) onto the computed parameters. This information is used to feed a fuzzy logic system capable of estimating the effective radius and contact length. Furthermore, a verification process has been carried out using CarSim simulation software to get the inputs for the fuzzy logic system at complex maneuvers.

Analysis of Vehicle Lateral Response During Regenerative Braking in a Turn

2016 ◽  
Author(s):  
C. S. Nanda Kumar ◽  
Shankar C. Subramanian
Keyword(s):  
Rear Wheel ◽  
Front Wheel ◽  
Lateral Acceleration ◽  
Regenerative Braking ◽  
Steering Wheel ◽  
Slip Angle ◽  
Lateral Response ◽  
Wheel Drive ◽  
Reference Track ◽  
The Impact

Regenerative braking is applied only at the driven wheels in electric and hybrid vehicles. The presence of brake force only at the driven wheels reduces the lateral traction limit of the corresponding tires. This impacts the vehicle lateral response, particularly while applying the regenerative brake in a turn. In this paper, a detailed study was made on the impact of regenerative brake on the vehicle lateral response in front wheel drive and rear wheel drive configurations on dry and wet asphalt road surfaces. Simulations were done considering a typical set of vehicle parameters with the IPG CarMaker® software for different drive conditions and braking configurations along the same reference track. The steering wheel angle, yaw rate, lateral acceleration, vehicle slip angle, and tire forces were obtained. Further, they were compared against the conventional all wheel friction brake configuration. The regenerative braking configuration that had the most impact on vehicle lateral response was analyzed and response variations were quantified.

Experimental Study on Tire Non-Steady State Slip Properties

2013 ◽  
Vol 753-755 ◽  
pp. 1736-1744
Author(s):  
Jie Liu ◽  
Xiao Ling Jia
Keyword(s):  
Linear System ◽  
Dynamic Performance ◽  
Lateral Force ◽  
Slip Angle ◽  
Test Results ◽  
Relaxation Length ◽  
Side Slip Angle ◽  
First Order ◽  
Depth Analysis ◽  
Yaw Angle

As for the two typical inputs of pure side slip angle and pure yaw angle, this paper presents the in-depth analysis of lateral force, aligning torque and relaxation length respectively within the domains of distance and spacial frequency, and also explains the test results by theoretical model. Within the small side slip angle, tire is a first-order linear system. Relaxation length is equivalent to the time constant of linear system, which decreases as slip angle increases. It indicates the dynamic performance of tire system.

Dynamics of Towed Cables With Active Controls

2002 ◽  
Author(s):  
Svein Ersdal ◽  
Odd M. Faltinsen
Keyword(s):  
Drag Coefficient ◽  
Cross Flow ◽  
Transient Behavior ◽  
Longitudinal Direction ◽  
Reynolds Numbers ◽  
Transverse Motion ◽  
Towed Cable ◽  
Speed Effect ◽  
Flow Drag ◽  
Transverse Response

The transverse dynamics of a towed cable was studied both experimentally and analytically. Forced oscillation was applied on the upstream end of a cable towed in its longitudinal direction, while transverse motion in the downstream end was restricted by springs. Reynolds numbers based on length were in the 6.5 − 32.5 × 106 range and cable length to diameter ratio was 1180. The amplitude of the forced motion was 4.55 diameters. The transverse response was measured at two locations and compared to results from computer simulation, showing that the model known as the Paidoussis equation overpredicted the response by a factor of two around resonance. Modification of force coefficients with respect to a modified KC number improved the results, but important trends were not captured. Curve fitting the cross flow drag coefficient to experimental data gave a result 3.3 times the drag coefficient past a cylinder in supercritical flow. The discrepancies are believed to be caused by forward speed effect on the formation of vortices and the transient behavior of the wake, but the physics of this is not clear.

Research for a Uniform Quality Grading System for Tires. II. Wheel Speed Capability Test

1969 ◽  
Vol 42 (5) ◽  
pp. 1450-1461
Author(s):  
F. C. Brenner ◽  
J. Mandel ◽  
B. G. Simson
Keyword(s):  
Laboratory Test ◽  
Size Range ◽  
Wheel Speed ◽  
Test Method ◽  
Grading System ◽  
Passenger Car ◽  
Quality Grading

Abstract The wheel speed capability of a tire is defined by a test method which determines the speed at which the tire fails on a laboratory test wheel. Data is reported on over 100 different passenger car tires of all grades and types over a range of sizes. A scaling system is devised for this property. It is found that the system produces consistent results for tires of given manufacturer's nominal grade across the size range tested and for samples produced several months apart.

Detection and Evaluation of Localized Damage under Creep-Fatigue Loading at 1000°F Using Acoustic Emission Technique

2006 ◽  
Vol 110 ◽  
pp. 45-54
Author(s):  
Kwang Hwan Oh ◽  
Jun Ho Jang ◽  
C.K. Jung ◽  
Kyung Seop Han
Keyword(s):  
Acoustic Emission ◽  
Fatigue Loading ◽  
Transient Behavior ◽  
Test Method ◽  
Full Time ◽  
Monitoring Method ◽  
Emission Parameter ◽  
Creep Fatigue ◽  
Cycle Dependent ◽  
Localized Damage

Acoustic emission (AE) technique was applied as a non-destructive test method to detect and evaluate the localized damage at high temperature environment. The creep-fatigue crack growth tests were carried out with the acquisition of AE signal at 1000°F. Under trapezoidal waveform loadings, AE results showed different features according to each damage mode. During the creep period, low and steady emissions were shown, while emissions were burst and high counts rate was recorded during the fatigue loading. Based on these characteristics, damage contribution was expressed in terms of acoustic emission parameter as a part-time monitoring method. Comparisons of damage contribution with respect to lifetime showed the transient behavior from cycle-dependent to time-dependent process. In case of full-time monitoring, bilinear behavior between AE counts and life was represented. From both monitoring results, it was confirmed that creep and fatigue damage can be characterized by means of emission features and AE is possible way to evaluate the localized damage at elevated temperature.

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