Virtual Tyre Research Articles

Identifying vehicle characteristic target based on subjective ratings from drivers

In virtual tire development, defining vehicle characteristic target is crucial to achieving the desired vehicle performance with the equipped tires. Vehicle performance is generally evaluated through subjective ratings by skilled drivers following SAE J1441 guidelines, as well as the objective performance metrics obtained via vehicle dynamics analysis. However, due to the scarcity and bias in real-world testing dataset, the vehicle characteristic target cannot be determined definitively. To address this issue, we propose a recommendation system that searches the unexplored vehicle characteristic domains. This suggested method provides virtual subjective ratings to enrich the limited real-world dataset from the skilled drivers. Moreover, we highlight the correlation between subjective and objective data using vehicle and tire dynamics simulation software. Based on this augmented data, we predict the vehicle characteristic target according to the subjective rating requirements. The proposed approach was validated through various experiments involving skilled drivers and various vehicle-tire combinations, showing 91.26% to 96.2% consistency in generated steering parameter domains. Domains of stability parameters show that one fewer domain was generated by a conservative driver compared to more lenient driver, which confirms the robustness of the proposed approach in accommodating individual driver preferences.

Fidelity of Finite Element–Based Virtual Tire Assembly Models Used for Vehicle Noise, Vibration, and Harshness Structural-Borne Noise Performance Considering Vibrational Modal and Steady-State Dynamic Simulation

ABSTRACT The increasing presence of battery electric vehicles brings about new challenges to the noise, vibration, and harshness performance of tires. One of the new challenges involves the expansion of frequency range for structural-borne noise virtual predictions. Current standard virtual tire simplifies the tire geometry as an axisymmetric body, neglecting the effect of complex tread pattern. It is perceived that this simplification can lead to prediction error for a tire’s structural-borne noise performance at mid-frequency range (250∼500 Hz). This study investigates how different tread pattern representation affects the structural-borne noise prediction. This study uses linear, steady-state dynamics finite element simulations of a modified SAE J2710 test and traveling sinusoid test. The resulting frequency responses of the virtual tires and the computational time to obtain each frequency response are compared. The comparison shows that while including the 3D tread pattern does show some differences under certain conditions, it is not necessary to use this technique for every case, especially during the early evaluation stage.

Parking-Specific Parameterization Method for FTire

ABSTRACT Virtual steering system layout in the early development phase requires adequate tire models to predict realistic steering rack forces. An accurate representation of parking is particularly important, as the largest steering rack forces occur during this maneuver. Physical tire models are mainly parameterized for rolling conditions. Since the tire exhibits different mechanical behavior under nonrolling conditions, this article introduces a new parameterization procedure for the physical tire model FTire that characterizes the conditions during parking maneuvers. To this end, an additional full vehicle measurement setup is used to understand the tire motions, forces, and torques during parking. It is also shown that a tire model based on a standard parameterization procedure results in steering speed-dependent parking torque deviations of up to 17.5% when compared with component measurements. Thus, new measurement methods are developed to help parameterize the tire model for this maneuver. A linear friction tester is used to determine the friction interaction between tire and road at the relevant relative velocities. In addition, measurements are performed on a tire stiffness test rig, in which translatory and rotatory movements are overlaid. Furthermore, the contact patch shape, ground pressure distribution, and tire outer contour are digitalized and added into the model. A tire model based on the new parking optimized parameterization is then compared with the standard tire modeling approach and component measurements as well as the full vehicle measurements. In conclusion, improvements of up to 12% for drilling torque, up to 15% for longitudinal force, a more realistic lateral stiffness, a more realistic pressure distribution, and improvements of up to 8% when simulating the steering rack force can be stated. After the results are evaluated and interpreted, recommendations for future developments of this parameterization procedure and an extension of the virtual tire model are discussed.

Clinical efficacy of occlusive splints manufactured by computer modeling and volumetric printing in patients with bruxism: research results and a clinical case

BACKGROUND: Among dental diseases, various types of musculoskeletal dysfunctions occupy a special place. The myogenic theory of temporomandibular joint dysfunction is interesting, where the fundamental role is assigned to the parafunctional state of the masticatory muscles. Analysis of the results of electromyographic studies has shown that patients with TMJ disorders complicated by muscle hypertension have significant functional disorders of the masticatory muscles. Also, the causes of TMJ dysfunction include bruxism, which can occur against the background of parafunctions of the masticatory muscles. To date, there are a large number of methods for the treatment of TMJ dysfunction: splint therapy, occlusive and immobilizing splints. CAD/CAM computer technologies have also become widespread, which are used for the manufacture of these structures. But there are no uniform treatment standards, therefore, studies and comparisons of different techniques are relevant.
 AIM: the effectiveness of treatment of patients with bruxism by developing a clinical protocol for the use of an occlusive splint made by volumetric printing.
 MATERIAL AND METHODS: To evaluate the effectiveness of occlusive splints manufactured by computer milling and 3D printing in patients with bruxism. All study participants at the stage of formation of clinical groups underwent a comprehensive dental examination, which included a clinical and instrumental examination, surface electromyography of the masticatory muscles, computer monitoring of occlusion, cone-beam computed tomography of the TMJ. To exclude the somatoform component from the pathogenesis of bruxism, an electroencephalogram (EEG) was performed in all patients at the stage of formation of clinical groups. At the first stage of treatment, all patients underwent selective grinding of centric and eccentric interferences under the control of a T-scan computer occlusion monitoring device, after which the therapeutic position of the mandible was determined, stabilizing nocturnal occlusal splints made by volumetric printing were manufactured and fixed. Monitoring of treatment results included clinical and instrumental examination and surface electromyography of the masticatory muscles, carried out 3.6 and 12 months after the start of treatment. Upon completion of treatment, an assessment of the integrity of occlusal splints was carried out.
 RESULTS: According to the results of the performed myography, at the time of the start of treatment, the PU coefficient was 74%, after 3 months, it significantly decreased by 6%, after 6 months, its decrease was recorded by 11%, and after 12 months by 16%. The assessment of the integrity of the occlusal splint was carried out at the end of treatment after 12 months, by combining virtual tire models in a computer program before and after the start of treatment obtained by laboratory scanning. When analyzing the comparison of virtual tire models, their almost complete identity was revealed, with the exception of one area on the occlusal surface, which is 0.044 mm, which is not critical in the general treatment concept.
 CONCLUSION: Taking into account the positive result of clinical testing of the proposed technology, it is advisable to conduct a randomized study to evaluate the effectiveness of the use of occlusive splints made by computer modeling and volumetric printing from domestic material in the treatment of patients with musculoskeletal dysfunction complicated by bruxism.

Enhancing Hierarchical Multiscale Off-Road Mobility Model by Neural Network Surrogate Model

Abstract A hierarchical multiscale off-road mobility model is enhanced through the development of an artificial neural network (ANN) surrogate model that captures the complex material behavior of deformable terrain. By exploiting the learning capability of neural networks, the incremental stress and strain relationship of granular terrain is predicted by the ANN representative volume elements (RVE) at various states of the stress and strain. A systematic training procedure for ANN RVEs is developed with a virtual tire test rig model for producing training data from the discrete-element (DE) RVEs without relying on computationally intensive full vehicle simulations on deformable terrain. The ANN surrogate RVEs are then integrated into the hierarchical multiscale computational framework as a lower-scale model with the scalable parallel computing capability, while the macroscale terrain deformation is described by the finite element (FE) approach. It is demonstrated with several numerical examples that off-road vehicle mobility performances predicted by the proposed FE-ANN multiscale terrain model are in good agreement with those of the FE-DE multiscale model while achieving a substantial computational time reduction. The accuracy and robustness of the ANN RVE for fine-grain sand terrain are discussed for scenarios not considered in training datasets. Furthermore, a drawbar pull test simulation is presented with the ANN RVE developed with data in the cornering scenario and validated against the full-scale vehicle test data. The numerical results confirm the predictive ability of the FE-ANN multiscale terrain model for off-road mobility simulations.

A new approach in modelling of hitch joint of a tractor semi-trailer using virtual Pacejka tyre model

A new approach in modelling of hitch joint of a tractor semi-trailer using virtual Pacejka tyre model

On tyre force virtual sensing for future Automated Vehicle-Based Objective Tyre Testing (AVBOTT)

ABSTRACTIn this paper, a novel Automated Vehicle-Based Objective Tyre Testing (AVBOTT) concept is introduced. In brief, AVBOTT pursues the development of inexpensive automated testing vehicles capable of executing a set of standardised manoeuvres and generate large amounts of tyre data rapidly and inexpensively. Naturally, the costs associated with current vehicle instrumentation and, in particular, with Wheel Force Transducers (WFT) prevent this concept from realisation at the moment. In order to overcome this limitation, a cost-effective alternative to WFT is proposed in this paper to estimate the tyre forces using indirect measurement techniques. Specifically, for the first time, the validity of random-walk virtual tyre force sensors for vehicle-based objective tyre testing is studied comprehensively. Moreover, the suitability of Adaptive Neuro-Fuzzy Inference Systems (ANFIS) to extract relevant tyre attributes in a systematic manner from lateral and longitudinal dynamics manoeuvres is analysed in detail. The proposed solutions are assessed in a complete tarmac tyre testing program carried out at IDIADA with a fully instrumented experimental vehicle. Additional winter testing activities performed at Revi facilities (Sweden) complete the experimental evaluation at different mu levels.

Sophisticated but quite simple contact calculation for handling tire models

Handling tire models like Pacejka (Tire and Vehicle Dynamics, 3rd edn., Elsevier, Amsterdam, 2012) or TMeasy (Rill in Proc. of the XV Int. Symp. on Dynamic Problems of Mechanics, Buzios, RJ, Brazil, 2013) consider the contact patch as one coherent plane. As a consequence, the irregularities of a rough road profile must be approximated by an appropriate local road plane that serves as an effective road plane in order to calculate the geometric contact point and the corresponding contact velocities. The Pacejka/SWIFT tire model employs a road enveloping model that generates the effective height and slope by elliptical cams. TMeasy just uses four representative road points for that purpose. In addition, TMeasy replaces the geometric contact point by the static contact point and shifts it finally to the dynamic contact point that represents the point where the contact forces are applied. In doing so, a rather sophisticated but still simple contact calculation is possible. Simulations obtained with a virtual tire test rig and fully nonlinear three-dimensional multibody system models of a motor-scooter and a passenger car demonstrate the potential of this contact approach.

Virtual tyre force sensors: An overview of tyre model-based and tyre model-less state estimation techniques

This paper presents a comprehensive literature review on tyre force estimation and road grip recognition approaches. With the development of modern automotive control systems, a precise estimation of a large number of vehicle states is necessary to guarantee a robust actuation of the controller. Moreover, the estimation of these states must be carried out in a cost-effective and reliable way. The aim of this work is to provide a solid base for the development of automotive virtual sensors, and in particular, virtual tyre force sensors. An initial overview of the tyre force estimation problem is provided in the first section. Tyre and vehicle modelling, as well as observers for vehicle state estimation, are covered in detail in the second section. The third section introduces a brief discussion regarding the main limitations of direct tyre force measurement approaches. In the following sections, relevant works regarding three-axis tyre force estimation and road grip recognition are discussed. The review is structured around longitudinal force estimation, lateral force estimation, combined tyre force estimation, tyre self-alignment torque estimation and vertical tyre force estimation. Within each section, the most significant road grip identification approaches are introduced. An additional section, Road slope and bank angle compensation, describes relevant work on estimation methods for global chassis orientation. A brief summary of the presented approaches is provided in the section Summary of presented approaches. Finally, relevant conclusions and further research steps are given in the last section.

Method for virtual tyre and braking distance simulation

Method for virtual tyre and braking distance simulation

A multi-laser sensor system to measure rolling deformation for truck tyres

The rolling deformation of a tyre is a direct result of tyre-road interactions and therefore contains useful information for tyre design. This study proposes a multi-laser sensor system for rolling tyre deformation measurements and the methodology is illustrated in detail. On-board validation tests were conducted with a truck tyre under service conditions. Tyre inner contour changes due to the inflation and wheel load were measured. In addition, non-uniform tread deformations were observed within the contact patch. In the longitudinal direction, asymmetric tread deformations which have direct links to rolling resistance were observed, while, in the lateral direction, the tread deformation pattern were found related to the inflation pressure and wheel load. The preliminary measurement results demonstrate the feasibility of the proposed system as a tool for investigations on tyre-road interactions and validations of virtual tyre models.

A multi-laser sensor system to measure rolling deformation for truck tyres

The rolling deformation of a tyre is a direct result of tyre-road interactions and therefore contains useful information for tyre design. This study proposes a multi-laser sensor system for rolling tyre deformation measurements and the methodology is illustrated in detail. On-board validation tests were conducted with a truck tyre under service conditions. Tyre inner contour changes due to the inflation and wheel load were measured. In addition, non-uniform tread deformations were observed within the contact patch. In the longitudinal direction, asymmetric tread deformations which have direct links to rolling resistance were observed, while, in the lateral direction, the tread deformation pattern were found related to the inflation pressure and wheel load. The preliminary measurement results demonstrate the feasibility of the proposed system as a tool for investigations on tyre-road interactions and validations of virtual tyre models.

Tyre model development using co-simulation technique for helicopter ground operation

This paper describes the development of a new aircraft tyre model applied using a co-simulation approach for the multibody dynamic simulation of helicopter ground vehicle dynamics. The new tyre model is presented using a point follower approach that makes a novel contribution to this area by uniquely combining elements of two existing tyre models used by the aircraft industry, namely the NASA R64 model developed by Smiley and Horne and the Engineering Sciences Data Unit (ESDU) Mitchell tyre model. Before the tyre model was used with a full helicopter model, a virtual tyre test rig was used to examine the tyre and to predict the tyre forces and moments for a range of tyre states. The paper concludes by describing the successful application of the new tyre model with a full helicopter model and the simulation of representative landing, take-off and runway taxiing manoeuvres. The predictive capability of the model is demonstrated to show the open-loop ground vehicle dynamics response of the helicopter and also the ground load predictive capability for the distribution of loads through the tyres, wheels and landing gears.

Tyre tread-block friction: modelling, simulation and experimental validation

Pneumatic tyres are used in vehicles since the beginning of the last century. They generate braking and steering forces for bicycles, motor cycles, cars, busses, trucks, agricultural vehicles and aircraft. These forces are generated in the usually very small contact area between tyre and road and their performance characteristics are of eminent importance for safety and comfort. Much research has been addressed to optimise tyre design with respect to footprint pressure and friction. In this context, the development of virtual tyre prototypes, that is, simulation models for the tyre, has grown to a science in its own. While the modelling of the structural dynamics of the tyre has reached a very advanced level, which allows to take into account effects like the rate-independent inelasticity of filled elastomers or the transient 3D deformations of the ply-reinforced tread, shoulder and sidewalls, little is known about the friction between tread-block elements and road. This is particularly obvious in the case when snow, ice, water or a third-body layer are present in the tyre–road contact. In the present paper, we give a survey on the present state of knowledge in the modelling, simulation and experimental validation of tyre tread-block friction processes. We concentrate on experimental techniques.

Effect of ambient temperature on stress, deformation and temperature of dump truck tire

The influence of the ambient temperature on the stress, deformation and temperature of a dump truck tire has been predicted with the virtual tire model established in this work by employing the finite element method (FEM) and Algor software. The nonlinear stress–strain relationship of tire rubber material has been given by Mooney–Rivlin material model. The hysteresis and loss strain energy density have been related to give the heat generation rate. A two-dimensional (2D) FE model of rolling radial tire has been built in Algor environment according to the actual construction of bridgestone 24.00R35 tire adopted for Caterpillar Earth Mover 775E Model. The model consists of the tread, belt, carcass, air filled volume and tire–rim interface. The material properties of the components and boundary conditions from tire–rim contact and tire–road contact are considered. The mechanical event simulation (MES) with nonlinear material model and the steady-state heat transfer analysis have been performed. The analysis results of the tire stress, deformation and temperature are presented under the ambient temperatures ranging from −40 to 40°C conditions at the Syncrude mine in Canada. The results show that the effect of the ambient temperature on the tire deformation is larger than on the tire stress. The increase of ambient temperature will cause the tire temperature rise. This study provides a comprehensive modeling and analysis that provide key to avoid tire temperature related failure.

Vehicle Lateral State Estimation Based on Measured Tyre Forces

Future active safety systems need more accurate information about the state of vehicles. This article proposes a method to evaluate the lateral state of a vehicle based on measured tyre forces. The tyre forces of two tyres are estimated from optically measured tyre carcass deflections and transmitted wirelessly to the vehicle body. The two remaining tyres are so-called virtual tyre sensors, the forces of which are calculated from the real tyre sensor estimates. The Kalman filter estimator for lateral vehicle state based on measured tyre forces is presented, together with a simple method to define adaptive measurement error covariance depending on the driving condition of the vehicle. The estimated yaw rate and lateral velocity are compared with the validation sensor measurements.

TMPT – conclusions and consequences for the industry from the industry

After a short introduction, the first part of this publication shows the main topics of vehicle dynamics from the computational simulation point of view: vehicle handling, comfort and durability. It is discussed, which effects of the physical tire behavior are included in different tire models for simulation. Additionally limitations of these models are given briefly. In the second part, the tire parameterization process is shown, starting from the tire measurement to the release of the tire data set. One essential point of this process is the validation and plausibility check of the virtual tire behavior. Finally, the general requirements of tire models are discussed, based on the results of the Tire Model Performance Test. The acknowledgment of the virtual tire characteristics is a fundamental part of correctly interpreting simulation results for decisions in the development process.

A new tyre–soil interaction model for vehicle simulation on deformable ground

In cooperation with the Ford Research Center Aachen the new tyre–soil interaction model AS2TM for MATLAB/Simulink was developed by Automotive Engineering, Software and Consulting (AESCO). The model is based on the principles introduced by Bekker [Bekker, M.G., 1956, Theory of Land Locomotion: The Mechanics of Vehicle Mobility (Ann Arbor, Michigan: University of Michigan Press); Bekker, M.G., 1960, Off the Road Locomotion (Ann Arbor, Michigan: University of Michigan Press); Bekker, M.G., 1960, Introduction to Terrain–Vehicle Systems (Ann Arbor, Michigan: University of Michigan Press).] and by Janosi and Hanamoto [Janosi, Z. and Hanamoto, B., 1961, Analytical determination of draw bar pull as a function of slip for tracked vehicles in deformable soils. Proceedings of the 1st International Conference of the International Society for Terrain–Vehicles Systems, Turin, Italy.] and takes advantage of more than a decade of research work in the field of terra-mechanics at the former Institut für Kraftfahrwesen und Kolbenmaschinen of the University of the Federal Armed Forces Hamburg under the charge of Professor I.C. Schmid. In this paper, firstly, the theoretical approach of AS2TM is discussed and the implementation of significant soft soil–elastic tyre interaction effects described and, secondly, the stand-alone model has been investigated and validated for steady-state conditions by using a virtual tyre test environment. Furthermore AS2TM is implemented as an S function into veDYNA applying the TYDEX standard tyre interface. The vehicle dynamic behaviour on deformable ground in a full vehicle simulation is highlighted and a comparison of the predicted vehicle performances on various terrains is presented.

Application of the tyre model FTire in the vehicle development process at MAGNA STEYR Fahrzeugtechnik

The first part of this paper briefly deals with the application fields of multibody systems and the software products applied for the automotive development process at MAGNA STEYR Fahrzeugtechnik. A great number of calculation tasks derived from the various application fields directly or indirectly consider vehicle-excited vibrations. After extensive analysis of the digitalized road surfaces, simulation rides on these surfaces are carried out by means of the vehicle model generated in MSC.ADAMS/Car. The tyre model FTire is coupled to the vehicle model. The data resulting from the tyre model tested on the virtual tyre test rig and on road surfaces with different excitations, depending on the unevenness, are explained in detail. Finally, a development-relevant question is dealt with, which among others shows the potential of this simulation technique with regard to minimization of the development risk.