scholarly journals Efficient In-Plane Tire Mode Identification by Radial-Tangential Eigenvector Compounding

2015 ◽  
Vol 43 (1) ◽  
pp. 71-84
Author(s):  
Vasilis Tsinias ◽  
George Mavros
Keyword(s):  
Experimental Studies ◽  
Modal Testing ◽  
Mode Shapes ◽  
Model Parameters ◽  
Tire Model ◽  
Mode Identification ◽  
Tire Dynamics ◽  
Efficient Processing ◽  
Noise Vibration ◽  
Tire Models

ABSTRACT Tire modal testing is frequently used for validation of numerical tire models and identification of structural tire model parameters. Most studies focus primarily on in-plane dynamic tire behavior and adopt the approach of the fixed boundary condition at the wheel center. Here, an identification method of in-plane tire dynamics was developed for the case of a free tire-rim combination. This particular case is important when the aim is to construct a full tire model, capable of predicting ride and noise, vibration, and harshness involving the whole vehicle, all from modal testing. Key attributes of the proposed approach include ease of implementation and efficient processing of measurements. For each type of excitation, i.e., radial and tangential, both radial and tangential responses were recorded. Compounding of the corresponding radial/tangential eigenvectors, which, in the context of the present work, refers to expressing the motion of the tire belt as a combination of the radial and tangential responses, results in smooth mode shapes that were found to agree with those published in other analytical and experimental studies.

Weighted Orthogonal Distance Regression for Tire Models Parameters Identification

2015 ◽  
Author(s):  
JoseLuis Olazagoitia ◽  
Alberto López
Keyword(s):  
Test Data ◽  
Measured Data ◽  
Model Parameters ◽  
Tire Model ◽  
Optimum Parameters ◽  
Ordinate Axis ◽  
Orthogonal Distance Regression ◽  
Independent Variable ◽  
Tire Models ◽  
Least Squares Techniques

Determining the parameters in existing tire models (e.g. Magic Formula (MF)) for calculating longitudinal and lateral forces depending on the tire slip is often based on standard least squares techniques. This type of optimization minimizes the vertical differences in the ordinate axis between the test data and the chosen tire model. Although the practice is to use this type of optimization in adjusting those model parameters, it should be noted that this approach disregards the errors that have been committed in the measurement of tire slips. These inaccuracies in the measured data affect the optimum parameters of the model, producing non optimum models. This paper presents a methodology to improve the fitting of mathematical tire models on available test data, taking into account the vertical errors together with errors in the independent variable.

Longitudinal Tire Dynamics Model for Transient Braking Analysis: ANCF-LuGre Tire Model

2015 ◽  
Vol 10 (3) ◽  
Author(s):  
Hiroki Yamashita ◽  
Yusuke Matsutani ◽  
Hiroyuki Sugiyama
Keyword(s):  
Structural Deformation ◽  
Model Parameters ◽  
Force Distribution ◽  
Force Model ◽  
Tire Model ◽  
Elastic Ring ◽  
Contact Patch ◽  
Tire Force ◽  
Tire Dynamics ◽  
Tire Friction

In this investigation, the flexible tire model based on the absolute nodal coordinate formulation (ANCF) is integrated with LuGre tire friction model for evaluation of the longitudinal tire dynamics under severe braking scenarios. The ANCF-LuGre tire model developed allows for considering the nonlinear coupling between the dynamic structural deformation of the tire and its transient tire force distribution in the contact patch using general multibody dynamics computer algorithms. To this end, the contact patch obtained by the ANCF elastic ring tire model is discretized into small strips and the state of friction at each strip is defined by the differential equation associated with the discretized LuGre friction parameters. The normal contact pressure distribution predicted by the ANCF elastic ring elements that are in contact with the road surface are mapped onto the LuGre strips in the contact patch to evaluate the tangential tire force distribution and then the tire forces evaluated at LuGre strips are fed back to the generalized tangential contact forces of the ANCF elastic ring tire model. By doing so, the structural deformation of the ANCF elastic ring tire model is dynamically coupled with the LuGre tire friction in the final form of the governing equations. Furthermore, the systematic and automated parameter identification procedure for the LuGre tire force model is developed. It is shown that use of the proposed procedure with the modified friction curve proposed for wet road conditions leads to accurate prediction of the LuGre model parameters for measured tire force characteristics under various loading and speed conditions. Several numerical examples are presented in order to demonstrate the use of the in-plane ANCF-LuGre tire model for the longitudinal transient dynamics of tires under severe braking scenarios.

scholarly journals Optimal parameter estimation in semi-empirical tire models

2018 ◽  
Vol 233 (1) ◽  
pp. 73-87 ◽  
Author(s):  
Alberto López ◽  
José Luis Olazagoitia ◽  
Francisco Marzal ◽  
María Rosario Rubio
Keyword(s):  
Optimal Parameter ◽  
Nonlinear Least Squares ◽  
Model Parameters ◽  
Tire Model ◽  
Independent Variables ◽  
Optimal Parameter Estimation ◽  
Reliable Parameter ◽  
Test Points ◽  
Semi Empirical ◽  
Tire Models

Semi-empirical tire models are mathematical models, the parameters of which are identified after a process of error reduction to fit experimental data obtained in the laboratory. In this process, the algorithms used for estimating the model parameters are usually based on nonlinear least-squares fitting methods, in which only vertical residuals between the model and the test points are considered. Although extensively utilized, this type of fitting implicitly considers that errors in the slip data (horizontal residuals) are either nonexistent or negligible, which is not true. This paper introduces a new methodology to the identification of semi-empirical tire model parameters based on weighed orthogonal residuals, which takes into account possible errors inherent in the test measurements of dependent and independent variables. The results show that the methodology offers a reliable parameter identification providing an even fitting for all the zones of the mathematical semi-empirical tire model.

Tire Vibration Modes and Tire Stiffness

2002 ◽  
Vol 30 (3) ◽  
pp. 136-155 ◽  
Author(s):  
B. G. Kao
Keyword(s):  
Vibration Modes ◽  
Tire Model ◽  
Static Stiffness ◽  
Wheel Load ◽  
Radial Stiffness ◽  
Modeling Concept ◽  
Tire Stiffness ◽  
Tire Dynamics ◽  
Tire Models ◽  
The Relationship

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.

Modeling Nonlinear Flexible Tire Belt in the Study of In-Plane Tire Dynamics

2007 ◽  
Author(s):  
Hiroyuki Sugiyama ◽  
Yoshihiro Suda
Keyword(s):  
High Frequency ◽  
Moving Boundary ◽  
Absolute Nodal Coordinate Formulation ◽  
Tire Model ◽  
Elastic Ring ◽  
Inertia Effects ◽  
Absolute Nodal Coordinate ◽  
Proposed Model ◽  
Tire Dynamics ◽  
Tire Models

In this investigation, a modeling procedure for a tire with flexible belt is developed. The elastic deformation of the belt is modeled using the finite element absolute nodal coordinate formulation which allows for describing large rotational motion and the nonlinear inertia effects; the curved structure of the flexible belt; and moving boundary resulting from tread/road interaction. Using a concept of elastic ring tire models, the sidewall flexibility of tires is modeled using circumferential/radial springs and dampers between the belt and rim, while the tangential tread/road contact force is modeled using friction elements defined at contact nodes within the curved belt elements. Numerical examples are presented in order to demonstrate the use of the flexible tire model developed in this investigation. Good agreements in the tire vibration characteristics obtained using the experiments and the proposed model are demonstrated. It is also shown that the proposed tire model can be used for assessing dynamic characteristics of tires in high frequency ranges resulting from the interaction to uneven roads.

A Modified Dugoff Tire Model for Combined-slip Forces

2010 ◽  
Vol 38 (3) ◽  
pp. 228-244 ◽  
Author(s):  
Nenggen Ding ◽  
Saied Taheri
Keyword(s):  
Vehicle Dynamics ◽  
Tire Model ◽  
Magic Formula ◽  
Model Based ◽  
Proposed Model ◽  
Road Friction ◽  
On Line ◽  
Double Lane Change ◽  
Tire Forces ◽  
Tire Models

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.

A Double Interaction Brush Model for Snow Conditions

2019 ◽  
Vol 47 (2) ◽  
pp. 118-140
Author(s):  
Artem Kusachov ◽  
Fredrik Bruzelius ◽  
Mattias Hjort ◽  
Bengt J. H. Jacobson
Keyword(s):  
Low Complexity ◽  
Large Set ◽  
Tire Model ◽  
Vehicle Handling ◽  
Real Time Applications ◽  
Snow Conditions ◽  
Double Interaction ◽  
Tire Models ◽  
Force Characteristics ◽  
Model Approach

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.

In-Plane Flexible Ring Tire Model—Part 1: Modeling and Parameter Identification

2018 ◽  
Vol 46 (3) ◽  
pp. 174-219 ◽  
Author(s):  
Bin Li ◽  
Xiaobo Yang ◽  
James Yang ◽  
Yunqing Zhang ◽  
Zeyu Ma
Keyword(s):  
Static Load ◽  
Model Parameters ◽  
Tire Model ◽  
Test Results ◽  
Lumped Mass ◽  
Virtual Test ◽  
Proposed Model ◽  
Particle Swarm Method ◽  
Vehicle Dynamic Simulation ◽  
Flexible Ring

ABSTRACT The tire model is essential for accurate and efficient vehicle dynamic simulation. In this article, an in-plane flexible ring tire model is proposed, in which the tire is composed of a rigid rim, a number of discretized lumped mass belt points, and numerous massless tread blocks attached on the belt. One set of tire model parameters is identified by approaching the predicted results with ADAMS® FTire virtual test results for one particular cleat test through the particle swarm method using MATLAB®. Based on the identified parameters, the tire model is further validated by comparing the predicted results with FTire for the static load-deflection tests and other cleat tests. Finally, several important aspects regarding the proposed model are discussed.

Use of ionic currents to identify and estimate parameters in models of channel blockade

1990 ◽  
Vol 259 (2) ◽  
pp. H626-H634
Author(s):  
C. F. Starmer ◽  
V. V. Nesterenko ◽  
F. R. Gilliam ◽  
A. O. Grant
Keyword(s):  
Time Course ◽  
Experimental Studies ◽  
Ionic Currents ◽  
Blocking Agent ◽  
Model Parameters ◽  
Protein Conformations ◽  
Channel Blockade ◽  
Channel Blocking ◽  
Individual Contributions ◽  
Modulated Receptor

Models of ion channel blockade are frequently validated with observations of ionic currents resulting from electrical or chemical stimulation. Model parameters for some models (modulated receptor hypothesis) cannot be uniquely determined from ionic currents. The time course of ionic currents reflects the activation (fraction of available channels that conduct in the presence of excitation) and availability of channels (the ability of the protein to make a transition to a conducting conformation and where this conformation is not complexed with a drug). In the presence of a channel blocking agent, the voltage dependence of availability appears modified and has been interpreted as evidence that drug-complexed channels exhibit modified transition rates between channel protein conformations. Because blockade and availability both modify ionic currents, their individual contributions to macroscopic conductance cannot be resolved from ionic currents except when constant affinity binding to a bindable site is assumed. Experimental studies of nimodipine block of calcium channels and lidocaine block of sodium channels illustrate these concepts.

Investigating the vibrational behaviour of a rotating two-blade propeller by using a self-tracking method

2018 ◽  
Vol 233 (3) ◽  
pp. 835-847 ◽  
Author(s):  
Mohammad-Reza Ashory ◽  
Farhad Talebi ◽  
Heydar R Ghadikolaei ◽  
Morad Karimpour
Keyword(s):  
Natural Frequency ◽  
Measurement Errors ◽  
Mode Shapes ◽  
Model Parameters ◽  
Test Results ◽  
Modal Assurance Criterion ◽  
Tracking Method ◽  
Strong Resemblance ◽  
Test Scenarios ◽  
Good Agreement

This study investigated the vibrational behaviour of a rotating two-blade propeller at different rotational speeds by using self-tracking laser Doppler vibrometry. Given that a self-tracking method necessitates the accurate adjustment of test setups to reduce measurement errors, a test table with sufficient rigidity was designed and built to enable the adjustment and repair of test components. The results of the self-tracking test on the rotating propeller indicated an increase in natural frequency and a decrease in the amplitude of normalized mode shapes as rotational speed increases. To assess the test results, a numerical model created in ABAQUS was used. The model parameters were tuned in such a way that the natural frequency and associated mode shapes were in good agreement with those derived using a hammer test on a stationary propeller. The mode shapes obtained from the hammer test and the numerical (ABAQUS) modelling were compared using the modal assurance criterion. The examination indicated a strong resemblance between the hammer test results and the numerical findings. Hence, the model can be employed to determine the other mechanical properties of two-blade propellers in test scenarios.

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