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Development of a Vehicle Model/Simulation Evaluation Tool

SAE International Journal of Commercial Vehicles

Systems Technology, Inc.-J. Gavin Howe, Jeffrey P. Chrstos
RealTime Technologies, Inc.-Richard Romano
  • Journal Article
  • 2008-01-0778
Published 2008-04-14 by SAE International in United States
As part of the evaluation of vehicle simulation models, a vehicle dynamics engineer typically desires to compare simulation results to test data from actual vehicles and/or results from known, or higher fidelity simulations. Depending on the type of model, several types of tests and/or maneuvers may need to be compared. For military vehicles, there is the additional requirement to run specific types of maneuvers for vehicle model evaluations to ensure that the vehicle complies with procurement requirements. A thorough evaluation will run two different categories of tests/maneuvers. The first category consists of laboratory type tests that include weight distribution, kinematics and compliance, steering ratio, and other static measures. The second category consists of dynamic maneuvers that include handling, drive train, braking, ride, and obstacle types. In this paper, a process for proper evaluation of vehicle simulation models is presented. A method for evaluating simulation results from different simulation programs is also presented.
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Further Analysis of Potential Road/Terrain Characterization Rating Metrics

Systems Technology, Inc.-J. Gavin Howe, Dong-Chan Lee, Jeffrey P. Chrstos, Ole Balling, Thomas T. Myers, R. Wade Allen
U.S. Army TARDEC-David J. Gorsich, Alexander Reid
Published 2005-11-01 by SAE International in United States
The U.S. Army uses the root mean square and power spectral density of elevation to characterize road/terrain (off-road) roughness for durability. This paper describes research aimed toward improving these metrics. The focus is on taking previously developed metrics and applying them to mathematically generated terrains to determine how each metric discerns the relative roughness of the terrains from a vehicle durability perspective. Multiple terrains for each roughness level were evaluated to determine the variability for each terrain rating metric. One method currently under consideration is running a relatively simple, yet vehicle class specific, model over a given terrain and using predicted vehicle response(s) to classify or characterize the terrain.
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A Biodynamic Model for the Assessment of Human Operator Performance under Vibration Environment

Systems Technology, Inc.-Chi-Ying Liang, Raymond Magdaleno, Dongchan Lee, David H. Klyde, R. Wade Allen
Intrinsic, Inc.-Kristin Overmeyer
Published 2005-06-14 by SAE International in United States
A combined biodynamic and vehicle model is used to assess the vibration and performance of a human operator performing driving and other tasks. The other tasks include reaching, pointing and tracking by the driver and/or passenger. This analysis requires the coordinated use of separate and mature software programs for anthropometrics, vehicle dynamics, biodynamics, and systems analysis. The total package is called AVB-DYN, an acronym for Anthropometrics, Vehicle and Bio-DYNamics. The biodynamic component of AVB-DYN is described, and then compared with an experiment that studied human operator in-vehicle reaching performance using the U.S. Army TACOM Ride Motion Simulator.
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Analysis of Potential Road/Terrain Characterization Rating Metrics

Systems Technology, Inc.-J. Gavin Howe, Dong-Chan Lee, Jeffrey P. Chrstos, Thomas T. Myers, R. Wade Allen
U.S. Army TARDEC-David J. Gorsich, Alexander Reid
Published 2004-10-26 by SAE International in United States
The U.S. Army uses the root mean square and power spectral density of elevation to characterize road/terrain (off-road) roughness for durability. This paper describes research aimed toward improving these metrics. The focus is on taking previously developed metrics and applying them to mathematically generated terrains to determine how each metric discerns the relative roughness of the terrains from a vehicle durability perspective. Multiple terrains for each roughness level were evaluated to determine the variability for each terrain rating metric. One method currently under consideration is running a relatively simple, yet vehicle class specific, model over a given terrain and using predicted vehicle response(s) to classify or characterize the terrain.
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Combined Terrain, Vehicle, and Digital Human Models Used for Human Operator Performance Analysis

Systems Technology, Inc.-Peter M. Thompson, Chi-Ying Liang, David H. Klyde, R. Wade Allen
Published 2004-06-15 by SAE International in United States
A combined biodynamic and vehicle model is used to assess the vibration and performance of a human operator performing driving and other tasks. The other tasks include reaching, pointing and tracking by the driver and/or passenger. This analysis requires the coordinated use of separate and mature software programs for anthropometrics, vehicle dynamics, biodynamics, and systems analysis. The total package is called AVB-DYN, an acronym for Anthropometrics, Vehicle, and Bio-DYNamics. The objectives and architecture are discussed, and then a preliminary version of this package is demonstrated in an example where a HMMWV (High Mobility Multipurpose Wheeled Vehicle) operator is performing a driving task.
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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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Parachute training and mission rehearsal using a simulator synthetic environment

Systems Technology, Inc.-Jeffrey R. Hogue, R. Wade Allen
SSK Industries, Inc.-Cliff Schmucker
  • Technical Paper
  • 2002-11-0009
Published 2002-05-08 by Royal Aeronautical Society in United Kingdom
This paper describes a low-cost, virtual-reality-based, parachute-maneuvering simulator that has evolved over the years to train a wide range of jumping tasks encountered by smoke jumpers, pilots, airborne troops and special operations personnel. The simulator represents chute deployment, malfunctions, maneuvering, and landing. Recent advancements allow for several jumpers to be networked together for coordinated jumps, and the simulated use of a GPS navigational aid system. This paper discusses the evolution of the simulator capabilities for range of jumping tasks and situations, including recent enhancements for mission rehearsal and networking.
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Driver/Vehicle Modeling and Simulation

Systems Technology, Inc.-R. Wade Allen, Jeffrey P. Chrstos, Bimal L. Aponso, Dongchan Lee
Published 2002-05-07 by SAE International in United States
This paper describes the driver/vehicle modeling aspects of a computer simulation that can respond to highway engineering descriptions of roadways. The driver model interacts with a complete vehicle dynamics model that has been described previously. The roadway path is described in terms of horizontal and vertical curvature and cross slopes of lanes, shoulders, side slopes and ditches. Terrain queries are made by the vehicle dynamics to locate tires on the roadway cross-section, and to define vehicle path and road curvature at some distance down the road. The driver model controls steering to maintain lateral lane position. Speed is maintained at a speed limit on tangents, and decreased as needed to maintain safe lateral acceleration. Because the bandwidth of longitudinal (speed) control is much lower than lateral/directional (steering) control, the driver model looks further ahead for speed control than for steering.The paper considers numerous examples of the path and speed control ability of the driver model in response to horizontal and vertical curvature. The driver model must slow down, and brake if necessary, to avoid excessive…
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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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