Browse Topic: Traction

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Traction Voltage Level in Two-Wheelers: Considerations on Safety and Performance2024-32-006204/18/2025
Most electric 2-wheelers on the market today seek to replace combustion engine vehicles from 50cc to 150cc which equates to an electric motor power between 2 and 12 kW. The traction voltage level of these vehicles is mostly between 44V and 96V. However, the actual choice of voltage on a specific vehicle seems to be arbitrary and higher voltage does not necessarily correlate with higher motor power. This paper seeks to highlight considerations and tradeoffs which feed the choice of traction voltage levels. Important criteria are electrical safety standards and their impact on vehicle electrical architecture, the performance and availability of key electronics parts such as capacitors, MOSFETs, and gate drivers, while also highlighting functional safety aspects. This paper shows by a comprehensive analysis of the motor drive that for the vehicle class mentioned above the traction voltage level can be kept below 60V without any performance impact, while also ensuring electrical and
Schmitt, Stefan
Technical Paper
Nonlinear Joint Dynamic Estimator of Sideslip Angle and Tire-Road Peak Adhesion Coefficient Based on Improved Brush Tire Model2024-01-703312/13/2024
The sideslip angle and tire-road peak adhesion coefficient (TRPAC) are crucial parameters for intelligent active safety systems in automobiles. The accuracy and real-time estimation of these parameters significantly affect control effectiveness. And there is a strong coupling between the two parameters, which brings great challenges to the joint estimation. This paper proposes a nonlinear dynamic estimator that pre-estimates tire lateral force to achieve synchronous estimation of sideslip angle and TRPAC. Additionally, to cope with sudden changes in road adhesion condition, a TRPAC preliminary estimation optimization algorithm is introduced. Moreover, an adaptive gain adjustment algorithm for the sideslip angle estimator is implemented to address large lateral excitation conditions. Simulation results on various road surfaces and under various lateral excitation conditions demonstrate that the proposed joint estimator enables accurate and rapid estimation of sideslip angle and TRPAC.
Zhao, Wenrui, Leng, Bo, Han, Yinfeng, Yu, Zhuoping, Xiong, Lu
Technical Paper
Recurrent Neural Network Model for On-Board Estimation of the Side-Slip Angle in a Four-Wheel Drive and Steering Vehicle15-17-01-000309/23/2023
Abstract A valuable quantity for analyzing the lateral dynamics of road vehicles is the side-slip angle, that is, the angle between the vehicle’s longitudinal axis and its speed direction. A reliable real-time side-slip angle value enables several features, such as stability controls, identification of understeer and oversteer conditions, estimation of lateral forces during cornering, or tire grip and wear estimation. Since the direct measurement of this variable can only be done with complex and expensive devices, it is worth trying to estimate it through virtual sensors based on mathematical models. This article illustrates a methodology for real-time on-board estimation of the side-slip angle through a machine learning model (SSE—side-slip estimator). It exploits a recurrent neural network trained and tested via on-road experimental data acquisition. In particular, the machine learning model only uses input signals from a standard road car sensor configuration. The model
Giuliacci, Tiziano Alberto, Ballesio, Stefano, Fainello, Marco, Mair, Ulrich, King, Julian
Journal Article
Recurrent Neural Network Model for On-Board Estimation of the Side-Slip Angle in a Four-Wheel Drive and Steering Vehicle15-17-01-0003-TEST-REC09/23/2023
Abstract A valuable quantity for analyzing the lateral dynamics of road vehicles is the side-slip angle, that is, the angle between the vehicle’s longitudinal axis and its speed direction. A reliable real-time side-slip angle value enables several features, such as stability controls, identification of understeer and oversteer conditions, estimation of lateral forces during cornering, or tire grip and wear estimation. Since the direct measurement of this variable can only be done with complex and expensive devices, it is worth trying to estimate it through virtual sensors based on mathematical models. This article illustrates a methodology for real-time on-board estimation of the side-slip angle through a machine learning model (SSE—side-slip estimator). It exploits a recurrent neural network trained and tested via on-road experimental data acquisition. In particular, the machine learning model only uses input signals from a standard road car sensor configuration. The model
Giuliacci, Tiziano Alberto, Ballesio, Stefano, Fainello, Marco, Mair, Ulrich, King, Julian
Journal Article
STANDARD FOR TIRE TRACEABILITY CONTENT AND FORMAT FOR THE RADIO-FREQUENCY IDENTIFICATION (RFID) TAG AND ASSOCIATED TIRE DATA SETUSCAR39-1 (Current)11/19/2020
This standard describes a requirement for automotive tire traceability. It includes a definition of the RFID tag and the associated tire data set that can be accessed using the RFID tag as an identifier. The standard describes a unique identification and the associated data set for each tire produced by the tire fabricator. This data will either be provided or transmitted at the time of shipment to retailers, wholesalers or original equipment vehicle manufacturers. Tire identification code and data may be used for error proofing, determining the tire specifications or supporting any inquiries that occur for the duration of its automotive life.
USCAR
Specification
Experimental Study of Tread Rubber Compound Effects on Tire Performance on Ice02-13-02-000606/16/2020
Mechanical and thermal properties of the rubber compounds of a tire play an important role in the overall performance of the tire when it is in contact with the terrain. Although there are many studies conducted on the properties of the rubber compounds of the tire to improve some of the tire characteristics, such as the wear of the tread, there are a limited number of studies that focused on the performance of the tire when it is in contact with ice. This study is a part of a more comprehensive project looking into the tire-ice performance and modeling. In this study, to understand the effect of different rubber compounds on the tire performance, three identical tires from the same company have been chosen. The tires’ only difference is the material properties of the rubber. Two approaches have been implemented in this study. For the first approach, several tests were conducted for the chosen tires at Terramechanics, Multibody, and Vehicle Systems (TMVS) laboratory at Virginia Tech to
Mousavi, Hoda, Sandu, Corina
Journal Article
Comparative Study on the Effects of the Tread Rubber Compounds on Tire Tractive performance on Ice2020-01-122804/14/2020
Mechanical and thermal properties of the rubber compounds of a tire play an important role in the overall performance of the tire when it is in contact with the train. Although there are many studies conducted on the properties of the rubber compounds of the tire to improve some of the tire characteristics such as the wear of the tread, there is a limited number of studies that focus on the performance of the tires on ice. This study is part of a more comprehensive study to investigate the effect of rubber compounds on performance of the tire on ice. In this study three tires that are completely identical in terms of tire parameters (such as tire dimensions, treat pattern, tire structure, inflation pressure, etc., but have different tread rubber compounds have been investigated. Several tests have been conducted for the chosen tires in three modes: free rolling, braking, and traction using the Terramechanics Rig at TMVS at Virginia Tech. In this presentation we will only focus on the
Mousavi, Hoda, Sandu, Corina
Technical Paper
Investigation of Cabin Noise while Accelerating on Low Mu Track through Simulation Approach Using Full Vehicle ADAMS/Car Model2019-26-017901/09/2019
Cabin noise is a significant product quality criteria which enables the customers for product differentiation. There are various sources of cabin noise such as wind, structures(panels), engine, suspension, tire and roads. During product development phase, extensive tests has been conducted to improve vehicle dynamics behavior on various climatic conditions. One such test is accelerating vehicle on low mu or icy surface. While performing acceleration manoeuvre (tractions) on a low mu tracks, Cabin noise with source identified from front underbody & low tractive torque build up is reported. This undesirable behavior may occur due to following reason (1) Excitation of coupled modes between suspension and powertrain which induces torque fluctuation. (2) Transmissibility of various subsystem can be the reason for above problem statement. (3) Poorly chosen tire compounds and design leads to fluctuation in torque. A detailed simulation based study using ADAMS/CAR has been performed to assess
Singh, Vivek, Prasad, Tej, Srivastava, Harshit
Technical Paper
Modeling Cruise Control Initiated Wheelspin in Rear Wheel Drive Vehicles2018-01-500005/04/2018
There are driving situations in which a rear-wheel-drive vehicle, operating with an active closed-loop cruise control, can experience wheelspin and a subsequent oversteer/loss of control. The situations involve low-μ surfaces (ice), weather-related phenomenon (rear-wheel hydroplaning), slope-climbing or a combination of these external effects. Although traction control and stability control, depending on the sophistication of the system, can negate many of these situations, the active fleet contains many vehicles not equipped with these features. In the present work, we calculate the conditions under which cruise-control-initiated rear wheel spin can occur.
Metz, L. Daniel
Technical Paper
Investigation of a Six-Phase Interior Permanent Magnet Synchronous Machine for Integrated Charging and Propulsion in EVs08-07-02-000604/17/2018
Merits such as reduced weight, overall and operational costs of the electric vehicle (EV) while providing level 3 charging capability, are propelling research on integrated charging (IC) technology for EVs. Since the same interior permanent magnet synchronous machine (IPMSM) is used during IC and traction conditions, it is important to understand the behavior of the machine during these conditions and optimally design the machine. Hence, firstly, this paper presents a case study on performance of a laboratory 3-phase IPMSM under IC and traction conditions. Thereafter, understanding the challenges such as low magnet operating point, losses and torque oscillation in 3-phase IPMSM during IC, a 6-phase IPMSM with an unconventional configuration is investigated to yield traction characteristics like that of the 3-phase IPMSM and mitigate challenges during IC. In the process, mathematical model of the 6-phase IPMSM is developed employing the dq-axis theory. The developed model is then
Lai, Chunyan, Dhulipati, Himavarsha, Mukundan, Shruthi
Journal Article
A Smart Gate Driver with Active Switching Speed Control for Traction Inverters2017-01-124303/28/2017
The IGBTs are dominantly used in traction inverters for automotive applications. Because the Si-based device technology is being pushed to its theoretical performance limit in such applications during recent years, the gate driver design is playing a more prominent role to further improve the traction inverter loss performance. The conventional gate driver design in traction inverter application needs to consider worst case scenarios which adversely limit the semiconductor devices' switching speed in its most frequent operation regions. Specifically, when selecting the gate resistors, the IGBT peak surge voltage induced by fast di/dt and stray inductance must be limited below the device rated voltage rating under any conditions. The worst cases considered include both highest dc bus voltage and maximum load current. However, the traction inverter operates mainly in low current regions and at bus voltage much lower than the worst case voltage. This paper proposes a low-cost and simple
Zhou, Yan, Chen, Lihua, Yang, Shuitao, Xu, Fan, Alam, Mohammed Khorshed
Journal Article
Tire Tread Performance Modification Utilizing Polymeric Additives2017-01-150203/28/2017
Tire manufacturers have long grappled with the challenge of balancing the conflicting tire attributes of traction, rolling resistance, and treadwear. Improvements to one of these “magic triangle” attributes often comes at the expense of the other attributes. Recent regulations have further increased the pressure on manufacturers to produce optimized tires with minimal performance compromises. In order to meet this challenge, the tire industry is looking to new material systems beyond the traditional tire tread components. Polymeric materials beyond the base elastomers and processing oils used in tread provide opportunities to modify the physical and viscoelastic properties of tread. In this study, various polymeric materials were evaluated as additives in a model tire tread formulation. Hydrocarbon resin, high styrene resin, and thermoplastic styrene elastomers were added to the model formulation at various loading levels and through various addition strategies. The thermal behavior of
Harper, Madeline, Tardiff, Janice, Haakenson, Daniel, Joandrea, Maria, Knych, Matthew
Journal Article
A Hybrid Approach to Model the Temperature Effect in Tire Forces and Moments2017-01-967603/14/2017
Tire is an integral part of any vehicle which provides contact between the vehicle and the surface on which it moves. Forces and moments generated at the tire-road interaction imparts stability and control of motion to the vehicle. These forces and moments are functions of many variables such as slip, slip angle, contact pressure, inflation pressure, coefficient of friction, temperature, etc. This paper deals with the effect of temperature on the lateral force, the longitudinal force and the self-aligning moment. The analysis is done at different tire surface temperatures such as 20°C, 40°C, and 60°C. Since the experimental set up with the mounted tire is complex and expensive, we use a hybrid approach in which we take the results from the experiments done by the researchers on a sample piece of tire rubber at various temperatures. Then, we do the steady state analysis in ABAQUS considering the variation of coefficient of friction, slip speed and the elastic modulus of rubber with
S, Bibin, Pandey, Ashok Kumar
Journal Article
Off-Road Tire Replacement GuidelinesJ2611_201702 (Current)02/13/2017
This SAE information report covers the basic guidelines concerning off-road tire conditions that warrant replacement, removal, or repair. This material can assist the tire user in establishing specific written procedures for each job site.
MTC8, Tire and Rim
Information Report
Off-Road Tire-Terrain Interaction: An Analytical Solution2016-01-802909/27/2016
A novel semi-analytical solution has been developed for the calculation of the static and dynamic response of an off road tire interacting with a deformable terrain, which utilizes soil parameters independent of the size of the contact patch (size-independent). The models involved in the solution presented, can be categorized in rigid and/or pneumatic tires, with or without tread pattern. After a concise literature review of related methods, a detailed presentation of the semi-analytical solution is presented, along with assumptions and limitations. A flowchart is provided, showing the main steps of the numerical implementation, and various test cases have been examined, characterized in terms of vertical load, tire dimensions, soil properties, deformability of the tire, and tread pattern. It has been found that the proposed model can qualitatively capture the response of a rolling wheel on deformable terrain.
Papazafeiropoulos, George, Prins, Jan, Bekakos, Chrysostomos-Alexandros, O'Boy, Dan J., Mavros, George
Journal Article
A Fuzzy Inference System for Understeer/Oversteer Detection Towards Model-Free Stability Control2016-01-163004/05/2016
In this paper, a soft computing approach to a model-free vehicle stability control (VSC) algorithm is presented. The objective is to create a fuzzy inference system (FIS) that is robust enough to operate in a multitude of vehicle conditions (load, tire wear, alignment), and road conditions while at the same time providing optimal vehicle stability by detecting and minimizing loss of traction. In this approach, an adaptive neuro-fuzzy inference system (ANFIS) is generated using previously collected data to train and optimize the performance of the fuzzy logic VSC algorithm. This paper outlines the FIS detection algorithm and its benefits over a model-based approach. The performance of the FIS-based VSC is evaluated via a co-simulation of MATLAB/Simulink and CarSim model of the vehicle under various road and load conditions. The results showed that the proposed algorithm is capable of accurately indicating unstable vehicle behavior for two different types of vehicles (SUV and Sedan). The
Hirche, Benjamin, Ayalew, Beshah
Journal Article
Active Control of Structure-Borne Road Noise Based on the Separation of Front and Rear Structural Road Noise Related Dynamics2015-01-222206/15/2015
Axle forces from tire-road interaction can excite different structural resonances of the vehicle hence a high number of sensors is required for observing and separating all the vibrations dynamics that are coherent with the cabin noise. Feed-forward road noise control strategies adopted so far rely mainly on capturing these dynamics and thus the number of sensors constitutes one major limitation of this approach. Therefore there is a necessity for reducing the number of sensors without degrading the performance of an ANC system. In the past coherence function analysis has been found to be a useful tool for optimizing the sensor location. In this case coherence function mapping was performed between an array of vibration sensors and the headrest microphones in order to identify the locations on the structure that are highly correlated with road noise bands in the compartment. A vehicle with an advanced suspension system was used for applying the method and defining some locations as
Zafeiropoulos, Nikos, Ballatore, Marco, Moorhouse, Andy, Mackay, Andy
Journal Article
Driver Lane Change Prediction Using Physiological Measures2015-01-140304/14/2015
Side swipe accidents occur primarily when drivers attempt an improper lane change, drift out of lane, or the vehicle loses lateral traction. Past studies of lane change detection have relied on vehicular data, such as steering angle, velocity, and acceleration. In this paper, we use three physiological signals from the driver to detect lane changes before the event actually occurs. These are the electrocardiogram (ECG), galvanic skin response (GSR), and respiration rate (RR) and were determined, in prior studies, to best reflect a driver's response to the driving environment. A novel system is proposed which uses a Granger causality test for feature selection and a neural network for classification. Test results showed that for 30 lane change events and 60 non lane change events in on-the-road driving, a true positive rate of 70% and a false positive rate of 10% was obtained.
Murphey, Yi lu, Kochhar, Dev S., Watta, Paul, Wang, Xipeng, Wang, Tianyu
Journal Article
Advanced Rolling Mechanics Analysis (AROMA) 1.0TBMG-2186504/01/2015
AROMA uses a boundary-element formulation to calculate normal and shear pressure distributions and sub-surface stresses for elastic bodies in contact. In addition to handling static normal and sheer loading, it also solves the contact problem for rolling elements such as bearings, traction drives, and wheel-to-rail interfaces. AROMA is a powerful and flexible tool for studying the tractive forces that arise during rolling in combination with kinematic effects, such as creepage and spin that are related to rolling element alignment. This GUI-based tool was developed in MATLAB, and can run within the MATLAB environment or as a standalone application.
Magazine Article
A Novel Method for Side Slip Angle Estimation of Omni-Directional Vehicles2014-01-030304/01/2014
The omni-directional vehicle is an innovative vehicle, in which the in-wheel steering motor and in-wheel driving motor are integrated into each wheel of the vehicle so that each wheel can be independently controlled to have traction, braking, and turning motions to improve the vehicle's mobility, handling and stability. To realize good performance, various control strategies have been proposed, like the active steering control and the direct yaw moment control, where the accurate slip angle information is critical to these control strategies. However, in practice, the side slip angle is hard or expensive to be measured for a passenger vehicle, therefore, different estimation methods have been proposed in the literature. In this paper, a novel side slip angle estimation method is proposed for the omni-directional vehicle that has four independent steering motors. This method includes the estimation of total alignment torque and side slip angle, and only needs the measurements of
Li, Boyuan, Du, Haiping, Li, Weihua
Journal Article
Development of Algorithms for Increasing Tire Grip through Frequency Response System of the Chassis and the Spring-Damper System2013-01-289711/27/2013
The paper concentrates on generating maximum tire grip by using the frequency response system of individual automobile components. Tire data has been consulted for and used to verify the findings presented in this paper. The tire data has been provided by the FSAE Tire Test Consortium (TTC) & Calspan Tire Research Facility (TIRF), U.S.A. specifically for FSAE/FS teams. Tire parameters such as vertical load, tire temperature, tire pressure, etc. have been given highest weightage as they directly affect the major force outputs in addition to frequency excitement. Suspension geometry design and its role as a precursor to an effective shock absorbing setup have been highlighted here. The damping has been calculated and algorithms related to it have been presented here since effective and quick response of the vehicle's behaviour can be modified through this. Frequency algorithms have been generated after crosschecking with tire data that aim at maximizing tire grip. The base automobile
M. Rao, Prasad
Technical Paper
UniTire Model for Tire Forces and Moments under Combined Slip Conditions with Anisotropic Tire Slip Stiffness2013-01-236209/24/2013
The tire mechanics characteristics are essential for analysis, simulation and control of vehicle dynamics. This paper develops the UniTire model for tire forces and moments under combined slip conditions with anisotropic tire slip stiffness. The anisotropy of tire slip stiffness, which means the difference of tire longitudinal slip stiffness and cornering stiffness, will cause that the direction of tire resultant shear stress in adhesion region is different from that in sliding region. Eventually the tire forces and moments under combined slip conditions will be influenced obviously. The author has proposed a “direction factor” before to modify the direction of resultant force in the tire-road contact patch, which can describe tire forces at cornering/braking combination accurately. However, the aligning moments which are very complicated under combined slip conditions are not considered in previous analysis. The simplified physical tire model is introduced firstly in this paper to
Xu, Nan, Guo, Konghui, Zhang, Xinjie
Journal Article
Enhancement of Collision Mitigation Braking System Performance Through Real-Time Estimation of Tire-road Friction Coefficient by Means of Smart Tires2012-01-201409/24/2012
In the case of modern day vehicle control systems employing a feedback control structure, a real-time estimate of the tire-road contact parameters is invaluable for enhancing the performance of the chassis control systems such as anti-lock braking systems (ABS) and electronic stability control (ESC) systems. However, at present, the commercially available tire monitoring systems are not equipped to sense and transmit high speed dynamic variables used for real-time active safety control systems. Consequently, under the circumstances of sudden changes to the road conditions, the driver's ability to maintain control of the vehicle maybe at risk. In many cases, this requires intervention from the chassis control systems onboard the vehicle. Although these systems perform well in a variety of situations, their performance can be improved if a real-time estimate of the tire-road friction coefficient is available. Existing tire-road friction estimation approaches often require certain levels
Singh, Kanwar Bharat, Arat, Mustafa Ali, Taheri, Saied
Journal Article
Enhancement of Collision Mitigation Braking System Performance Through Real-Time Estimation of Tire-road Friction Coefficient by Means of Smart Tires2012-01-2014-TEST-REC09/24/2012
In the case of modern day vehicle control systems employing a feedback control structure, a real-time estimate of the tire-road contact parameters is invaluable for enhancing the performance of the chassis control systems such as anti-lock braking systems (ABS) and electronic stability control (ESC) systems. However, at present, the commercially available tire monitoring systems are not equipped to sense and transmit high speed dynamic variables used for real-time active safety control systems. Consequently, under the circumstances of sudden changes to the road conditions, the driver's ability to maintain control of the vehicle maybe at risk. In many cases, this requires intervention from the chassis control systems onboard the vehicle. Although these systems perform well in a variety of situations, their performance can be improved if a real-time estimate of the tire-road friction coefficient is available. Existing tire-road friction estimation approaches often require certain levels
Singh, Kanwar Bharat, Arat, Mustafa Ali, Taheri, Saied
Journal Article
SAE Powertrain & Energy 2012-07-2512DPE072507/25/2012
The row about rare earths Rare-earth elements are key to applications as varied as traction motors, catalytic converters, and wind turbines, but high prices and supply shortages have the auto industry grappling with design changes and other alternatives.
Magazine
Long-Life, Lightweight, Multi-Roller Traction Drives for Planetary Vehicle Surface ExplorationTBMG-1356705/01/2012
NASA’s initiative for Lunar and Martian exploration will require long lived, robust drive systems for manned vehicles that must operate in hostile environments. The operation of these mechanical drives will pose a problem because of the existing extreme operating conditions. Some of these extreme conditions include operating at a very high or very cold temperature, operating over a wide range of temperatures, operating in very dusty environments, operating in a very high radiation environment, and operating in possibly corrosive environments.
Magazine Article
Fatigue Life Assessment of Welded Structures with the Linear Traction Stress Analysis Approach2012-01-052404/16/2012
Structural stress methods are now widely used in fatigue life assessment of welded structures and structures with stress concentrations. The structural stress concept is based on the assumption of a global stress distribution at critical locations such as weld toes or weld throats, and there are several variants of structural stress approaches available. In this paper, the linear traction stress approach, a nodal force based structural stress approach, is reviewed first. The linear traction stress approach offers a robust procedure for extracting linear traction stress components by post-processing the finite element analysis results at any given hypothetical crack location of interest. Pertinent concepts such as mesh-insensitivity, master S-N curve, fatigue crack initiation and growth mechanisms are also discussed. Then, fatigue life assessment of automotive exhaust systems is conducted and the data correlation with a recently developed equilibrium data analysis method is provided and
Wei, Zhigang, Yang, Fulun, Luo, Limin, Avery, Katherine, Dong, Pingsha
Journal Article
Development of Front-Wheel-Drive ELSD for Efficient Performance and Safety2012-01-030504/16/2012
The open (standard) differential provides an important function in vehicle dynamics and handling by splitting the applied driveline torque and allowing each wheel or axle to spin at different speeds. This function is necessary to eliminate axle bind-up while negotiating turns. However, it inherently impedes optimal traction and mobility performance by allowing the available torque to be limited by the wheel or axle having the least amount of traction. Loss of traction could result in loss of driveline torque control and a resulting loss of vehicle control. This loss of control could be catastrophic in the case of higher speed maneuvers. The proposed electronically controlled hydraulic limited slip differential solution corrects this problem, seamless to the driver, while maintaining the fundamental open differential function. Furthermore, this system maintains efficient forward motion compared to other solutions that slow the vehicle down while expending valuable energy. A number of
Fox, Matthew, Grogg, John
Technical Paper
From Atoms to Autos: Mathematical Modeling Across Length Scales for the Design and Integration of Traction BatteriesTP-AAB-AABC_US_2011_0501/28/2011
Presentation of "From Atoms to Autos: Mathematical Modeling Across Length Scales for the Design and Integration of Traction Batteries" for AABC US 2010.
Han, Taeyoung, Jagannathan, Kamakshi, Narayanrao, Ramakrishnan, Qi, Yue, Vanimisetti, Sampath, Verbrugge, Mark
Technical Paper
Spring TireTBMG-898901/03/2011
The spring tire is made from helical springs, requires no air or rubber, and consumes nearly zero energy. The tire design provides greater traction in sandy and/or rocky soil, can operate in microgravity and under harsh conditions (vastly varying temperatures), and is non-pneumatic.
Magazine Article
Battery in the loop: Real traction batteries on the virtual proving goundTP-AAB-US_2010_P_2405/21/2010
Validation of the durability, the reliabilty and the modularity of battery system concepts for HEV/EV applications
Schweiger, M.R., Le Rhun, F.
Technical Paper
Influence of Suspension Kinematics and Damper Asymmetry on the Dynamic Responses of a Vehicle under Bump and Pothole Excitations2010-01-113504/12/2010
Automotive suspensions invariably exhibit asymmetric damping properties in compression and rebound, which is partly attributed to asymmetric damping and in-part to the suspension linkage kinematics together with tire lateral compliance. Although automotive suspensions have invariably employed asymmetric damping, the design guidelines and particular rationale for such asymmetry has not been explicitly defined. The influences of damper asymmetry together with the suspension kinematics and tire lateral compliance on the dynamic responses of a vehicle are investigated analytically under bump and pothole excitations, and the results are interpreted in view of potential design guidance. A quarter-car kineto-dynamic model of the road vehicle employing a double wishbone type suspension comprising a strut with linear spring and multiphase asymmetric damper is formulated for the analyses. The simulation results revealed conflicting sprung mass acceleration responses under idealized bump and
Balike, Krishna Prasad, Rakheja, Subhash, Stiharu, Ion
Technical Paper
Controlled Braking Experiments with and without ABS2010-01-010004/12/2010
An experimental program to measure braking characteristics developed under emergency braking conditions by ABS-equipped vehicles was designed and performed. Variables examined included initial braking speed, vehicle type, tire pressure and data recording equipment utilized. All experiments were conducted on a closed airport taxiway constructed of sharp, brushed and heavily striated concrete. Tests were conducted with and without activated ABS systems on the test vehicles. Results showed that (1) with the ABS activated, faint roadway markings were visible only under a very few special circumstances, (2) tire/road μ-values and corresponding deceleration values varied only slightly for differing speeds and ABS conditions, (3) tire pressure made little difference in limited test results, and (4) there were differences in recorded results depending on the equipment used for data acquisition.
Metz, L. Daniel, Meyers, Duane
Technical Paper
Studies of Dynamic Fracture in Brittle MaterialsTBMG-508404/01/2009
A program of research spanning several years ending in November 2005 was dedicated primarily to formulation and analysis of canonical boundary- value problems in mathematical modeling of dynamic fracture in brittle materials. The sub-topics within the broad topic of dynamic fracture in brittle materials that were studied, and the accomplishments in each sub-topic, are summarized as follows:
Magazine Article
Studies of Dynamic Fracture in Brittle MaterialsTBMG-TB-00508403/30/2009
Several studies have contributed to understanding of fracture mechanisms. A program of research spanning several years ending in November 2005 was dedicated primarily to formulation and analysis of canonical boundary- value problems in mathematical modeling of dynamic fracture in brittle materials. The sub-topics within the broad topic of dynamic fracture in brittle materials that were studied, and the accomplishments in each sub-topic, are summarized as follows:
Magazine Article
Measurement Systems Aid NASA in Study of Space Station Solar Array AnomalyTBMG-354802/01/2009
Surface and roundness measurement systems Taylor Hobson West Chicago, IL 630-621-3099
Magazine Article
Longitudinal Interfacial Forces of the Interaction of a Treaded Tire with Snow2008-01-141504/14/2008
Although it is intuitively and qualitatively known that a treaded tire has a larger drawbar pull than a smooth tire, little is known quantitatively about all the interfacial forces and the origins of these forces of a treaded tire traversing a snow cover. There have been relatively few studies regarding the quantitative effects of tread pattern on tire-snow interaction due to the complexity of the tread pattern, the enormous amount of computational resources needed for high-fidelity numerical simulations, and the difficulty of measuring all the interfacial forces between a tire that is much harder than snow. The purpose of this paper is to understand the effects of a simplified tread pattern of a two-dimensional rigid tire on the interfacial forces between a tire and low-density snow. The parameters to vary included the wheel load, as well as a full-range of longitudinal slip. Snow sinkage, snow density, traction, motion resistance and drawbar pull were obtained as a function of input
Lee, Jonah H.
Journal Article
Novel Microsurface Machining Techniques for Improving the Traction Coefficient2008-01-041404/14/2008
This study examined methods of machining a microsurface texture on the surface of the rolling elements of a toroidal continuously variable transmission (CVT) for improving the traction coefficient. The microsurface texture of the toroidal surfaces consists of tiny circumferential grooves (referred to here as micro grooves) and a mirror-like surface finish similar to the rolling surface of bearings. Hard turning with a cubic boron nitride (cBN) cutting tool, grinding with a cBN wheel and micro forming were applied to machine the micro grooves. The results made clear the practical potential of each method. A micro forming device was also developed for use in actual production. A mirror-like surface finish and micro crowning of the convex portions of the microsurface texture were simultaneously executed by superfinishing them with a fine-grained elastic superfinishing stone. The results showed that a microsurface texture was successfully formed on the rolling elements of a toroidal CVT
Ota, Minoru, Nakayama, Tatsuomi, Nanbu, Toshikazu, Yasuda, Yoshiteru
Journal Article
Shape Optimization for Weight Reduction of Automotive Shell Structures Subject to a Strength Constraint2007-01-372008/05/2007
In this paper, we present a numerical solution to shape optimization problems in automotive shell structural designs subject to a strength constraint. Using the proposed method, the optimal shape can be obtained without any parameterization of design variables. With the aim of reducing the weight, a volume minimization problem subject to a von Mises stress constraint is formulated as a distributed-parameter shape optimization problem, or a non-parametric shape optimization problem. It is assumed that the design domain is varied in the tangential direction to the surface to maintain the curvatures of the initial shape. The shape gradient function and the optimality conditions are theoretically derived for this problem using the material derivative method, Lagrange multiplier method and the adjoint variable method. The traction method we have proposed earlier is applied to determine the smooth domain variation that minimizes the objective functional. The solution is applied to
Shimoda, Masatoshi, Tsuji, Jiro
Technical Paper
Multi-Scale Model of Failure in a Composite MaterialTBMG-457104/01/2007
An adaptive concurrent multilevel computational model of failure in a heterogeneous-material structure has been developed. As used here, “concurrent” is a term of art characterizing a class of structural/material models that (1) incorporate submodels representing material substructures at different spatial scales from macroscopic to microscopic, (2) the equations of the various models are solved simultaneously, and (3) the solutions at the various scales are coupled. The present model applies, more specifically, to a unidirectionalfiber/ matrix composite material structure. The model can be used to simulate and analyze the initiation and growth of damage, starting from microstructural damage in the form of debonding at fiber/matrix interfaces.
Magazine Article
Mathematical Modelling of Chassis Motion2006-01-346010/31/2006
This paper presents a mathematical approach for creating a vehicle model incorporating the characteristics of tires, suspension, forces acting at the tire/road interface, suspension forces, wind forces and gravitational forces. The model has been made for a middle class limousine. Two sets of equations, one set for the translatory motion and the other set for rotational motion have been derived. Torques, forces and angular or longitudinal velocities have been chosen as variables to act as interface between different sub - models. The complexity of the vehicle model created has been optimized for vehicle dynamics simulation. All the forces have been found in the undercarriage co-ordinate system. While substituting them in the equations of motion they are multiplied with the transformation matrix for the transformation from the undercarriage to the inertial co-ordinate system.
Jayakumar, M. Prem, Nanthakumar, A. J. D., Jawahar, P. Mannar
Technical Paper
Rolling Tire Vibration Caused by Road Roughness2005-01-252405/16/2005
To reduce tire/road noise, it is important to examine the noise generation mechanism. Noise generated by a rolling tire is mainly emitted from the tread block. However, it has recently been reported that smooth tires also generate noise recently. This paper remarks on a smooth tire vibration by rolling on the road. The vibration of a rolling smooth tire is mainly vibration excited from the road surface. It is difficult to measure the input from the road surface, so we measured the tire's vibration at the leading and trailing edges. Scan Laser Doppler Vibrometers were employed to measure the vibration of the tire tread.
Tsujiuchi, Nobutaka, Koizumi, Takayuki, Oshibuchi, Akira, Shima, Ichiro
Technical Paper
Wheel Traction Prediction - A Comparison Between Models and Experimental Data2004-01-270710/26/2004
The paper attempts to determine which traction model best fits with experimental data for a romanian lugged tractor tire. Different models for predicting net traction and traction efficiency for off-road conditions were considered. These models assume different tire-ground pressure distributions (constant, parabolic) over the undertread area and different contact patch length calculations. Experiments were conducted and the results were compared to the theoretical data. Two of the models are the best fit with the experimental data; both models assumed a parabolic pressure distribution over the undertread.
Radu, Rosca, Edward, Rakosi, Gheorghe, Manolache
Technical Paper
Efficiency Modeling in the Full Toroidal Variator: Investigation into Optimization of EHL Contact Conditions to Maximize Contact Efficiency2004-40-002208/23/2004
In the Full Toroidal Infinitely Variable Transmission (IVT) the transmission of power is through twelve elastohydrodynamic lubricated (EHL) contacts. In order to maximize the fuel economy benefits of the IVT, further focus has been placed on the optimization of the variator contact conditions to achieve optimum efficiency. Although much research has been undertaken on losses in EHL spinning and rolling contacts, the application of this research to the variator has not been investigated to the same level. Traditional theory of losses in spinning, rolling and sliding EHL contacts suggests that in order for the variator to be operating at its most efficient, the end-load or clamping force applied to the contacts should be controlled to give a traction coefficient of approximately 75% of peak traction coefficient. Current EHL models are used to validate this theory. However, in the application of the traditional theories to the IVT, the relationship between traction coefficient, endload
Newall, J.P., Cowperthwaite, S., Hough, M., Lee, A.P.
Technical Paper
Experimental Validation of Full Toroidal Fatigue Life2004-40-002108/23/2004
Whilst infinitely variable traction drive transmissions (IVT) have demonstrated the potential to provide significant fuel economy benefits through the optimisation of the vehicle powertrain, greater emphasis is now being placed on reducing the overall package size. The inevitable increase in power density places increased demands on the variator elements to withstand the heavily loaded rolling contact conditions. Described in this paper are the results of an experimental fatigue test program undertaken to establish the fatigue life of the variator rolling contacts when operating with the latest traction fluids. The experimental work utilised a number of full scale variator durability test rigs: all tests were conducted with real transmission contact operating conditions up to 220kW. Qualitative and quantitative analysis of the contact surfaces, including SEM, 3D area surface profile data and metallurgical analysis has been carried out. The fatigue results have enabled the interaction
Lee, Adrian P., Newall, Jonathan, Goto, Masao, Misada, Yasuharu, Ono, Yoshihiro
Technical Paper
A study of Blended Oil for Synergy Effect on Traction Coefficient2003-01-197905/19/2003
A series of blends of various compounds and plybutene were studied to clarify the structure development on the synergy effect on traction coefficient increase. The traction coefficient calculated from that of each component were compared with their actual values. Among the compounds investigated, it has been found that the compounds showed a synergy effect have common characteristics in their molecular structure. That is, they have two saturated cyclo rings linked with either ester or alkyl group.
Umemoto, Noboru
Technical Paper
Investigation of Shear Stresses in the Tire-Road Contact Patch2003-01-127303/03/2003
The paper presents some aspects of the experimental investigation of shear stresses in the tire-road contact patch. The rolling process is achieved by loading a freely rotating tire against a movable table. The rig structure, measuring stages, and special developed programs are mentioned. A comparison between treadless and pattern tread band design, pertaining to shear stress distribution, is presented. The influence of inflation pressure and normal force values on the shape and magnitude of the shear stresses is also shown.
Anghelache, Gabriel, Negrus, Eugen Mihai, Ciubotaru, Ovidiu
Technical Paper
Energy-Absorbing, Lightweight WheelsTBMG-123201/01/2003
Improved energy- absorbing wheels are under development for use on special-purpose vehicles that must traverse rough terrain under conditions (e.g., extreme cold) in which rubber pneumatic tires would fail. The designs of these wheels differ from those of prior non-pneumatic energy-absorbing wheels in ways that result in lighter weights and more effective reduction of stresses generated by ground/wheel contact forces. These wheels could be made of metals and/or composite materials to withstand the expected extreme operating conditions.
Magazine Article
The Theoretical Concepts for Pre-Extreme ABS2002-01-218507/09/2002
The analysis of existing systems of automotive active safety (SAS) shows that the antilock braking system (ABS) is a kernel for anyone of them. However circle of the tasks, which should be decided by SAS, is complicated, and the algorithms approaches are traditionally based on threshold control. Basing on the researches of interactions within a chain ‘automobile - wheel – road’ a new so-called pre-extreme control philosophy for ABS may be offered. It is based on the discovered regularities between the tire grip and wheel slippage. For the given philosophy the family of ABS algorithms is offered which allows realising both discrete and continuous control of wheel operation.
Ivanov, Valentin, Vysotsky, Michael, Boutylin, Vladimir, Lepeshko, Joseph
Technical Paper
Propagation of Error Applied to Linear Vehicle Dynamics2002-01-122303/04/2002
This paper applies basic statistics to the simulation of vehicle dynamics in the time domain and the frequency domain. The methods presented here yield an expectation for the variation of the computed results as a function of variation in input parameters. Applications include important steady state measures of vehicle performance such as understeer gradient and yaw rate gain. Follow up analysis includes measures of transient response in the time domain and of amplitude and phase relationships in the frequency domain. There are several potential applications for this methodology, perhaps most important, an understanding of the consequences of parameter uncertainty on the credibility of simulated results.
Buttars, Daniel J., Bernard, James E.
Technical Paper
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