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Rosenthal, Theodore J.
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Tire Modeling for Off-Road Vehicle Simulation

Systems Technology, Inc.-Chi-Ying Liang, R. Wade Allen, Theodore J. Rosenthal, Jeffrey P. Chrstos
TACOM / TARDEC-Patrick Nunez
Published 2004-05-04 by SAE International in United States
A tire/terrain interaction model is presented to support the dynamic simulation of off-road ground vehicle. The model adopts a semi-empirical approach that is based on curve fits of soil data combined with soil mechanics theories to capture soil compaction, soil shear deformation, and soil passive failure that associate with off-road driving. The resulting model allows the computation of the tire forces caused by terrain deformation in longitudinal and lateral direction. This model has been compared with experimental data and shown reasonable prediction of the tire/terrain interaction.
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Estimation of Passenger Vehicle Inertial Properties and Their Effect on Stability and Handling

Systems Technology, Inc.-R. Wade Allen, David H. Klyde, Theodore J. Rosenthal, David M. Smith
Published 2003-03-03 by SAE International in United States
Vehicle handling and stability are significantly affected by inertial properties including moments of inertia and center of gravity location. This paper will present an analysis of the NHTSA Inertia Database and give regression equations that approximate moments of inertia and center of gravity height given basic vehicle properties including weight, width, length and height. The handling and stability consequences of the relationships of inertial properties with vehicle size will be analyzed in terms of previously published vehicle dynamics models, and through the use of a nonlinear maneuvering simulation.
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The Relative Sensitivity of Size and Operational Conditions on Basic Tire Maneuvering Properties

Systems Technology, Inc.-R. Wade Allen, Theodore J. Rosenthal, David H. Klyde
Published 2002-03-04 by SAE International in United States
Basic performance properties of tires significantly influence the lateral/directional (steering) stability and handling of highway vehicles. These properties include cornering stiffness and peak and slide coefficients of friction. This paper considers some detailed tire machine measurements of lateral tire performance. A large database of tire properties for a wide range of highway vehicles is also analyzed. A regression analysis approach is used to define the sensitivity of various size and operational (speed, pressure and load) characteristics on tire behavior. The paper discusses the manner in which these properties vary with tire size and operational conditions, and the effect of the properties on vehicle stability and handling.
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Vehicle and Tire Modeling for DynamicAnalysis and Real-Time Simulation

Systems Technology. Inc-R. Wade Allen, Theodore J. Rosenthal, David H. Klyde, Jeffrey P. Chrstos
Published 2000-05-01 by SAE International in United States
This paper reviews the development and application of a computer simulation for simulating ground vehicle dynamics including steady state tire behavior. The models have been developed over the last decade, and include treatment of sprung and unsprung masses, suspension characteristics and composite road plane tire forces. The models have been applied to single unit passenger cars, trucks and buses, and articulated tractor/trailer vehicles. The vehicle model uses composite parameters that are relatively easy to measure. The tire model responds to normal load, camber angle and composite tire patch slip, and its longitudinal and lateral forces interact with an equivalent friction ellipse formulation. The tire model can represent behavior on both paved and off-road surfaces. Tire model parameters can be automatically identified given tire force and moment test data. The vehicle and tire models have been validated against real world test data, and can be used to analyze handling and stability including limit performance maneuvering. The models are efficient enough to run in real-time on Intel Pentium class PCs, and have been used in driving simulations…
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The Effect of Tire Characteristics on Vehicle Handling and Stability

Systems Technology, Inc-R. Wade Allen, Thomas T. Myers, Theodore J. Rosenthal, David H. Klyde
Published 2000-03-06 by SAE International in United States
Handling and stability problems are typically revealed under limit performance maneuvering conditions where tires are pushed to high slip angles under high normal loading conditions. This paper reviews vehicle dynamics handling and stability models relative to tire characteristics and examines tire testing data obtained under normal and extreme maneuvering conditions. Tire data is normalized according to design characteristics in order to reveal basic maneuvering behavior that is relatively independent of size and construction. Computer simulation analysis is used to demonstrate the influence of tire characteristics on handling and stability.
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Computer Simulation Analysis of Light Vehicle Lateral/Directional Dynamic Stability

Systems Technology, Inc-R. Wade Allen, Theodore J. Rosenthal, David H. Klyde, Jeffrey R. Hogue
Published 1999-03-01 by SAE International in United States
Dynamic stability is influenced by vehicle and tire characteristics and operating conditions, including speed and control inputs. Under limit performance operating conditions, maneuvering can force a vehicle into oversteer and high sideslip. The high sideslip results in limit cornering conditions, which might proceed to spinout, or result in tip-up and rollover. Oversteer and spinout result from rear axle tire side force saturation. Tip-up and rollover occur when tire side forces are sufficient to induce lateral acceleration that will overcome the stabilizing moment of vehicle weight. With the use of computer simulation and generic vehicle designs, this paper explores the vehicle and tire characteristics and maneuvering conditions that lead to loss of directional control and potential tip-up and rollover.
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A Low Cost PC Based Driving Simulator for Prototyping and Hardware-In-The-Loop Applications

JPC Engineering-Jeffrey P. Chrstos
Systems Technology, Inc.-R. Wade Allen, Theodore J. Rosenthal, Bimal L. Aponso, David H. Klyde, Fritz G. Anderson, Jeffrey R. Hogue
Published 1998-02-23 by SAE International in United States
This paper describes a low cost, PC based driving simulation that includes a complete vehicle dynamics model (VDM), photo realistic visual display, torque feedback for steering feel and realistic sound generation. The VDM runs in real-time on Intel based PCs. The model, referred to as VDANL (Vehicle Dynamics Analysis, Non-Linear) has been developed and validated for a range of vehicles over the last decade and has been previously used for computer simulation analysis. The model's lateral and longitudinal dynamics have 17 degrees of freedom for a single unit vehicle and 33 degrees of freedom for an articulated vehicle. The model also includes a complete drive train including engine, transmission and front and rear drive differentials, and complete, power assisted braking and steering systems. A comprehensive tire model (STIREMOD) generates lateral and longitudinal forces and aligning torque based on normal load, camber angle and horizontal (lateral and longitudinal) slip. The tire model correctly simulates saturation and can represent off-road behavior including plowing in soft soil at high sideslip angles. The articulated vehicle can simulate tractor/trailer rigs,…
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A Vehicle Dynamics Tire Model for Both Pavement and Off-Road Conditions

JPC Engineering-Jeffrey P. Chrstos
Systems Technology, Inc.-R. Wade Allen, Theodore J. Rosenthal
Published 1997-02-24 by SAE International in United States
This paper describes a tire model designed for the full range of operating conditions under both on- and off-road surface conditions. The operating conditions include longitudinal and lateral slip, camber angle and normal load. The model produces tire forces throughout the adhesion range up through peak coefficient of friction, and throughout the saturation region to limit slide coefficient of friction. Beyond the peak coefficient of friction region, the off-road portion of the model simulates plowing of deformable surfaces at large side slip angles which can result in side forces significantly above the normal load (e.g., equivalent coefficients of friction greatly exceeding unity).The model allows changing the saturation function depending the surface currently encountered by a given tire in the vehicle dynamics model. Saturation functions can vary from the sharp peak function associated with radial tires on paved surfaces, to the exponential like saturation associated with various off-road surfaces. Smooth transition functions are provided between the adhesion and saturation regions, and logic is provided to ensure that tire force always opposes slip velocity no matter what…
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Low Cost Driving Simulation for Research, Training and Screening Applications

Systems Technology, Inc.-R. Wade Allen, Theodore J. Rosenthal, Zareh Parseghian
Published 1995-02-01 by SAE International in United States
Interactive driving simulation is attractive for a variety of applications, including screening, training and licensing, due to considerations of safety, control and repeatability. However, widespread dissemination of these applications will require modest cost simulator systems. Low cost simulation is possible given the application of PC level technology, which is capable of providing reasonable fidelity in visual, auditory and control feel cuing. This paper describes a PC based simulation with high fidelity vehicle dynamics, which provides an easily programmable visual data base and performance measurement system, and good fidelity auditory and steering torque feel cuing. This simulation has been used in a variety of applications including screening truck drivers for the effects of fatigue, research on real time monitoring for driver drowsiness and measurement of the interference effect of in-vehicle IVHS tasks on driving performance. This paper discusses the characteristics of the simulation, including vehicle dynamics and visual, auditory and proprioceptive cueing and a unique scenario definition language (SDL) for defining driving scenarios and performance measurement. Potential low cost simulator applications are reviewed, along with issues…
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Tire Modeling Requirements for Vehicle Dynamics Simulation

Systems Technology, Inc.-R. Wade Allen, Raymond E. Magdaleno, Theodore J. Rosenthal, David H. Klyde, Jeffery R. Hogue
Published 1995-02-01 by SAE International in United States
The physical forces applied to vehicle inertial dynamics derive primarily from the tires. These forces have a profound effect on handling. Tire force modeling therefore provides a critical foundation for overall vehicle dynamics simulation. This paper will describe the role tire characteristics play in handling, and will discuss modeling requirements for appropriately simulating these effects. Tire input and output variables will be considered in terms of their relationship to vehicle handling. General computational requirements will be discussed. An example tire model will be described that allows for efficient computational procedures and provides responses over the full range of vehicle maneuvering conditions.
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