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Technical Paper
J.Y. Wong
With growing globalization of the economy, to gain a competitive edge in world markets shortening the product development cycle is crucial. Virtual product development is, therefore, being actively pursued in the off-road vehicle industry. To implement this process successfully, the development of comprehensive and realistic computer-aided methods for performance and design evaluation of off-road vehicles is of vital importance. To be useful to the engineer in industry for the development and design of new products, the computer-aided methods should take into account all major vehicle design parameters and pertinent terrain characteristics. They should be based on the understanding of the physical nature and the mechanics of vehicle-terrain interaction. Their capabilities should be substantiated by test data.
Journal Article
Brad Hopkins, Saied Taheri
Models for off-road vehicles, such as farm equipment and military vehicles, require an off-road tire model in order to properly understand their dynamic behavior on off-road driving surfaces. Extensive literature can be found for on-road tire modeling, but not much can be found for off-road tire modeling. This paper presents an off-road tire model that was developed for use in vehicle handling studies. An on-road, dry asphalt tire model was first developed by performing rolling road force and moment testing. Off-road testing was then performed on dirt and gravel driving surfaces to develop scaling factors that explain how the lateral force behavior of the tire will scale from an on-road to an off-road situation. The tire models were used in vehicle simulation software to simulate vehicle behavior on various driving surfaces. The simulated vehicle response was compared to actual maximum speed before sliding vs. turning radius data for the studied vehicle to assess the tire model.
Technical Paper
Edoardo Sabbioni, Silvia Negrini, Francesco Braghin, Stefano Melzi lng
The paper investigates the interaction between soil and tractor tires through a 2D numerical model. The tire is schematized as a rigid ring presenting a series of rigid tread bars on the external circumference. The outer profile of the tire is divided into a series of elements, each one able to exchange a normal and a tangential contact force with the ground. A 2D soil model was developed to compute the forces at the ground-tire interface: the normal force is determined on the basis of the compression of the soil generated by the sinking of the tire. The soil is modeled through a layer of springs characterized by two different stiffness for the loading (lower stiffness) and unloading (higher stiffness) condition. This scheme allows to introduce a memory effect on the soil which results stiffer and keeps a residual sinking after the passage of the tire. The normal contact force determines the maximum value of tangential force provided before the soil fails.
Technical Paper
Marco Mammetti, David Gallegos, Alex Freixas, Jordi Muñoz
The focus of the work is to carry out a study of the relative impact of the rolling resistance measurements on CO₂ emission and fuel consumption reduction for heavy-duty vehicles. For the purpose of the study, friction coefficients of the tires from tire test machine according to UN/ECE Regulation No 117 test procedure have been used. The rolling resistance coefficient has also been obtained from SAE J1263 and SAE J2263 procedure for coast-down determination on proving ground. The fuel consumption has been simulated and tested on the proving ground by following FIGE standard cycle and stabilized speed conditions. A simulation tool has been developed and validated by testing different rolling resistance coefficient tires, analyzing their effect on the fuel consumption. The analysis of the contribution of the tires to fuel consumption achieved on the test track has been correlated with the experimental results and those obtained from the simulation tool.
Technical Paper
Boris Beloousov, Tatiana I. Ksenevich, Vladimir Vantsevich, Dmitry Komissarov
Two characteristics of terrain mobility are essential in designing an unmanned ground vehicle (UGV): (i) the ability of a vehicle to move through terrain of a given trafficability and (ii) the obstacle performance, i.e., the ability to avoid, interact with and overcome obstacles encountered on a preset route of a vehicle. More attention has been given to the vehicle geometry including selection of the angles of approach and departure, radii of longitudinal and lateral terrain mobility, and the steering system configuration. An essential effect is exhibited by the tire properties in their interaction with the support surface; this, in turn, affects traction properties of the wheel and, thus, vehicle terrain mobility. However, the influence of power distribution between the driving wheels together with vehicle steering system on the two above-listed characteristics of terrain mobility has not been considered in depth.
Technical Paper
Douglas A. Swift, Carl Talaski
A sensor system was developed to measure loads in truck wheels. The system has the unique capability to measure each individual wheel in a dual set. This paper covers the development and testing of the system. Sample data from road tests is also presented.
Journal Article
Noor-u-Zaman Laghari
This paper presents a simulation based analysis of the effect of various non-linearities on vehicle handling of rigid and articulated vehicles. First a description of a non-linear vehicle model is presented and non-linearities, including tires, suspension elasto-kinematics, springing and damping are discussed. Later sections present the simulations results for the effects of each non-linearity. Simulation analyses are carried out for the case of step steering maneuvers, which permit to deduce the overall vehicle model response variation in steady-state and dynamic conditions.
Technical Paper
A. Uspenskiy, V. Boikov
Speed measurement accuracy of computers installed on wheeled tractors, not equipped with radar velocity transducers depends on the following: the rolling radius of the wheel to which the speed sensor is connected; the number of sensor's pulses per revolution; and algorithms used for processing the data that arrives from the speed sensor. The work deals with the effect of static tire characteristics and other factors influencing the speed measurement accuracy of wheeled tractors by means of on-board computers. Recommendations are given aimed at accuracy improvement when measuring tractor speed.
Technical Paper
Mark A. Bennett, William P. Amato
The accuracy of existing rotational wheel dynamics models has been found to be insufficient for heavy vehicle Antilock Braking System (ABS) and Electropneumatic Braking System (EBS) simulation, specifically when wheelspeeds are at or near zero but the vehicle speed is not. Control strategies specific to ABS and EBS, the low frequency response of pneumatic actuation, and the practice of using fewer modulators than braked wheels require that a vehicle model be able to handle lockedwheel scenarios accurately. Commercially available models have been found unsatisfactory in this regard, and technical literature has not been found to address this issue.
Journal Article
Kanwar Bharat Singh, Mustafa Ali Arat, Saied Taheri
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.
Technical Paper
Mustafa Ali Arat, Kanwar Singh, Saied Taheri
Active safety systems have become an essential part of today's vehicles including SUVs and LTVs. Although they have advanced in many aspects, there are still many areas that they can be improved. Especially being able to obtain information about tire-vehicle states (e.g. tire slip-ratio, tire slip-angle, tire forces, tire-road friction coefficient), would be significant due to the key role tires play in providing directional stability and control. This paper first presents the implementation strategy for a dynamic tire slip-angle estimation methodology using a combination of a tire based sensor and an observer system. The observer utilizes two schemes, first of which employs a Sliding Mode Observer to obtain lateral and longitudinal tire forces. The second step then utilizes the force information and outputs the tire slip-angle using a Luenberger observer and linearized tire model equations.
Technical Paper
Saurabh Kumar Singh, Vijay Hiremath, Vijay Kumar Ojha, Narayan Jadhav
Subject paper focuses primarily on non uniform tire wear problem of front steered wheels in a pickup model. Cause and effect analysis complemented with field vehicle investigations helped to identify some of the critical design areas. Investigation revealed that steering geometry of the vehicle is undergoing huge variations in dynamic condition as compared to initial static setting. Factors contributing to this behavior are identified and subsequently worked upon followed by a detailed simulation study in order to reproduce the field failures on test vehicles. Similar evaluation with modified steering design package is conducted and results are compared for assessing the improvements achieved. In usual practice, it is considered enough if Steering Geometry parameters are set in static condition and ensured to lie within design specifications.
Technical Paper
Nan Xu, Konghui Guo, Yiyang Yang
Abstract The tire mechanics characteristics are essential for analysis and control of vehicle dynamics. Basically, the effects of sideslip, longitudinal slip, camber angle and vertical load are able to be represented accurately by current existing tire models. However, the research of velocity effects for tire forces and moments are still insufficient. Some experiments have demonstrated that the tire properties actually vary with the traveling velocity especially when the force and moment are nearly saturated. This paper develops an enhanced brush tire model and the UniTire semi-physical model for tire forces and moments under different traveling velocities for raising need of advanced tire model. The primary effects of velocity on tire performances are the rubber friction distribution characteristics at the tire-road interface.
Technical Paper
Stefan Steidel, Thomas Halfmann, Manfred Baecker, Axel Gallrein
Abstract Rolling resistance and tread wear of tires do particularly influence the maintenance costs of commercial vehicles. Although tire labeling is established in Europe, it is meanwhile well-known that, due to the respective test procedures, these labels do not hold in realistic application scenarios in the field. This circumstance arises from the development phase of tires, where the respective performance properties are mainly evaluated in tire/wheel standalone scenarios in which the wide range of usage variability of commercial vehicles cannot be considered adequately. Within this article we address a method to predict indicators for rolling resistance and tread wear of tires in realistic application scenarios considering application-based factors of influence like specific customers, operation circumstances, regional dependencies, fleet specific characteristics etc.
Technical Paper
Chao Yang, Nan Xu, Konghui Guo
Abstract This paper focuses on the modeling process of incorporating inflation pressure into the UniTire model for pure cornering. Via observing and manipulating the tire experimental data, the effects of inflation pressure on the tire cornering property are analyzed in detail, including the impacts on cornering stiffness, the peak friction coefficient, the curvature of transition region and the pneumatic trail. And the brief mechanism explanations are also given for some of these impacts. The results show that some effects of inflation pressure are similar to that of vertical load on the non-dimensional tire cornering property, and there are strong interactive effects between the two operating conditions. Therefore, in order to obtain concise expressions, the inflation pressure is incorporated into the UniTire tire model by analogy with the expressions for vertical load, and the interactive effects are also taken into account.
Technical Paper
Chaitanya Ashok Vichare, Sivakumar Palanivelu
Abstract The fuel economy of heavy commercial vehicles can be significantly improved by reducing the rolling resistance of tires. To reduce the rolling resistance of 6×4 tractor, the super single tires instead of rear dual wheel tires are tried. Though the field trials showed a significant increase in fuel economy by using super single tires, it posed a concern of road safety when these tires blowout during operation. Physical testing of tire blowout on vehicle is very unsafe, time consuming and expensive. Hence, a full vehicle simulation of super single tire blowout is carried out. The mechanical properties of tires such as cornering stiffness, radial stiffness and rolling resistance changes during the tire blowout; this change is incorporated in simulation using series of events that apply different gains to these mechanical properties.
Technical Paper
Andrei Izmailov, Vladimir Shevtsov, Alexandr Lavrov, Zahid Godzhaev, Vladimir Pryadkin
Maximum pressure is an essential parameter determining the degree of environmental impact of pneumatic tractor wheels on soils. The authors of the paper offer a method for determining and adjusting maximum pressure of a pneumatic tractor wheels on the supporting surface. The paper contains an analysis of the variation of maximum pressure on soils for various values of internal tire pressure and vertical load on a wheel. The above method allows parameters for systems of monitoring and adjustment of maximum pressure on soils to be set up by measuring tire flexure and adjusting it through changing the internal air pressure.
Technical Paper
Arthur Larocca, Pablo Yugo Yoshiura Kubo, Dayane Rosa Buss, Luis Fernando de Mello Welin
Abstract One of the major challenges on the automotive industry is how to delineate a set of representative and real road loads, for reliability and efficiency during the validation stage on the development process. While several previous studies presented evaluations and results of the tire inflation pressure influence on the fuel consumption, driver comfort, vertical load and braking and handling performance, the objective of this work is to assess the influence of the tire pressure on the forces applied to a commercial vehicle’s steering system. In this regard, the steering link-rod of a truck has been instrumented and used as a load cell, in order to quantify the forces applied to the vehicle’s pitman arm on different tire inflation pressures. The measurements were performed in a static dry-park (lock-to-lock) maneuver and by decreasing the tire inflation pressure of the vehicle’s front loaded axle (6 tons) from 110 psi (7.6 bar) to 50 psi, in steps of 10 psi.
Technical Paper
Tianjun Zhu, Bin Li
Abstract A new extended planar model for multi-axle articulated vehicle with nonlinear tire model is presented. This nonlinear multi-axle articulated vehicle model is specifically intended for improving the model performance in operating regimes where tire lateral force is near the point of saturation, and it has the potential to extend the specific axles model to any representative configuration of articulated vehicle model. At the same time, the extended nonlinear vehicle model can reduce the model's sensitivity to the tire cornering coefficients. Firstly, a nonlinear tire model is used in conjunction with the 6-axle planar articulated vehicle model to extend the ranges of the original linear model into the nonlinear regimes of operation. Secondly, the performance analysis of proposed nonlinear vehicle model is verified through the double lane change maneuver on different road adhesion coefficients using TruckSim software.
Technical Paper
ASSERTING as a premise that highway legislation should be purely a matter of economics, the author draws a comparison between the costs of building a cheap road and hauling with 2½-ton trucks and building a heavier road and hauling with 5-ton trucks. He shows by this illustration that the latter proceeding is the more economical. Most States permit gross weights of vehicle and load that make it possible to haul pay-loads of about 5 tons. If 5-ton trucks show a saving in transportation costs over 2½-ton trucks, still larger capacity four-wheel trucks might show a corresponding saving over 5-ton trucks, from which it might be argued that all roads should be built sufficiently strong to carry the heavier vehicles and loads without damage. But it is pointed out that there are a great many secondary roads on which traffic is light, and that it is uneconomic to build roads and roadbeds stronger than is warranted by economic needs.
Technical Paper
Technical Paper
Austin M. Wolf's
Technical Paper
Austin M. Wolf
BOTH the tractor-semi-trailer and the six-wheel vehicle have the same number of axles and wheels and each has its own particular advantages. They are seldom competitive if the transportation problem is analyzed properly and legislation does not unduly oppress either. The six-wheeler has the advantage over the tractor-semi-trailer of weight saving, more traction if four driving wheels are used, lower insurance rates, and it is free from any “jack-knifing” proclivities. The chief distinction in the construction of six-wheelers depends upon the types of axles used, whether they be dead or driving. There are five classifications in use today, ranging in various combinations all the way from three driving axles to one. The rear bogie unit may have two driving axles or a driving and a trailing axle. There is a natural resistance to turning in a bogie unit since the wheels do not roll tangentially when the vehicle travels around a curve.
Technical Paper
Jared Johan Engelbrecht, Tony Russell Martin, Piyush M. Gulve, Nagarjun Chandrashekar, Amol Dwivedi, Peter Thomas Tkacik, Zachary Merrill
Abstract Most commercial heavy-duty truck trailers are equipped with either a two sensor, one modulator (2S1M) or four sensors, two modulator (4S2M) anti-lock braking system (ABS). Previous research has been performed comparing the performance of different ABS modules, in areas such as longitudinal and lateral stability, and stopping distance. This study focuses on relating ABS module type and wheel speed sensor placement to trailer wheel lock-up and subsequent impact to tire wear for tandem axle trailers with the Hendrickson air-ride suspension. Prior to tire wear inspection, functionality of the ABS system was testing using an ABS scan tool communicating with the SAE J1587 plug access port on the trailer. Observations were documented on trailers using the 2S1M system with the wheel speed sensor placed on either the front or rear axle of a tandem pair.
Technical Paper
Ankit Pant, Chetan Prakash Jain, Deepak Kumar Panda
For any new vehicle development, NVH target setting is crucial activity. Structural modification are to be done in early design phase to improve cabin comfort by identifying the sensitive paths and taking appropriate countermeasures for reduction of noise or vibrations transmission to cabin. A benchmark vehicle is taken to define the target areas for next model development. Numerical computations with suitably modified virtual model are carried out to accelerate the development cycle. Transfer path analysis (TPA) is an established technique for estimation and ranking of individual low-frequency noise or vibration contributions via the different structural transmission paths from point coupled powertrain or wheel-suspensions to the vehicle body [1]. TPA technique can also be used to define the improvement targets for future vehicles.
Technical Paper
null, R. P. Gaylord
THE cooperative tractor tire tests described in this paper were discussed originally at a meeting of the Society several years ago. The tractor engineers present at the discussion suggested to the tire engineers that there was need for a cooperative test program to determine the efficiency of the various tire sizes over a range of soil conditions. Among the ten conclusions drawn from the comprehensive tests reported in this paper are that the most important factor affecting the coefficient of traction or tire thrust of rubber-tired tractors is the nature or surface of the operating soil; that, for a given soil, the most important factor is the weight that the tire carries; and that inflation pressure has a relatively small effect.
Technical Paper
Technical Paper
Cheryl L. Greenly, James A. Beverly
The National Highway Traffic Safety Administration (NHTSA) realizes that medium and heavy vehicles have different issues than passenger vehicles with respect to tire pressure monitoring. The NHTSA did not have time during the one year deadline imposed by the Transportation Recall Enhancement, Accountability, and Documentation (TREAD) Act to address these complex concerns in its rulemaking.1 This paper explores the unique concerns that accompany commercial vehicle tire pressure monitoring and management that must be considered before a potential regulation for the commercial vehicle industry can be implemented successfully.
Viewing 1 to 30 of 576


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