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Technical Paper

The Relative Sensitivity of Size and Operational Conditions on Basic Tire Maneuvering Properties

2002-03-04
2002-01-1182
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.
Technical Paper

Combined Terrain, Vehicle, and Digital Human Models Used for Human Operator Performance Analysis

2004-06-15
2004-01-2152
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.
Technical Paper

A Biodynamic Model for the Assessment of Human Operator Performance under Vibration Environment

2005-06-14
2005-01-2742
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.
Technical Paper

Computer Simulation Analysis of Light Vehicle Lateral/Directional Dynamic Stability

1999-03-01
1999-01-0124
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.
Technical Paper

Motion Cueing Evaluation of Off-Road Heavy Vehicle Handling

2016-09-27
2016-01-8041
Motion cueing algorithms can improve the perceived realism of a driving simulator, however, data on the effects on driver performance and simulator sickness remain scarce. Two novel motion cueing algorithms varying in concept and complexity were developed for a limited maneuvering workspace, hexapod/Stuart type motion platform. The RideCue algorithm uses a simple swing motion concept while OverTilt Track algorithm uses optimal pre-positioning to account for maneuver characteristics for coordinating tilt adjustments. An experiment was conducted on the US Army Tank Automotive Research, Development and Engineering Center (TARDEC) Ride Motion Simulator (RMS) platform comparing the two novel motion cueing algorithms to a pre-existing algorithm and a no-motion condition.
Technical Paper

The Effect of Tire Characteristics on Vehicle Handling and Stability

2000-03-06
2000-01-0698
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.
Technical Paper

Vehicle and Tire Modeling for DynamicAnalysis and Real-Time Simulation

2000-05-01
2000-01-1620
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.
Technical Paper

A Vehicle Dynamics Tire Model for Both Pavement and Off-Road Conditions

1997-02-24
970559
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.
Technical Paper

Analysis and Computer Simulation of Driver/Vehicle Interaction

1987-05-01
871086
This paper presents an analysis of driver/vehicle performance over a range of maneuvering conditions including accident avoidance scenarios involving vehicle limit performance handling. Driver behavior is considered in the same dynamic analysis terms as vehicle response in order to give appropriate closed-loop measures of total system maneuvering capability and handling stability. A driver control structure is developed along with closed-loop system stability constraints on model parameters over a wide range of vehicle maneuvering conditions. Example simulation runs are presented for several accident avoidance scenarios.
Technical Paper

Tire Modeling for Off-Road Vehicle Simulation

2004-05-04
2004-01-2058
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.
Technical Paper

Driver Car Following Behavior Under Test Track and Open Road Driving Condition

1997-02-24
970170
This paper describes the results of an experiment concerning driver behavior in car following tasks. The motivation for this experiment was a desire to understand typical driver car following behavior as a guide for setting the automatic control characteristics of an ACC (Adaptive Cruise Control) system. Testing was conducted under both test track and open road driving conditions. The results indicate that car following is carried out under much lower bandwidth conditions than typical steering processes. Dynamic analysis shows driver time delay in response to lead vehicle velocity change on the order of several seconds. Typical longitudinal acceleration distributions show standard deviations of less than 0.05 g (acceleration due to gravity).
Technical Paper

Estimation of Passenger Vehicle Inertial Properties and Their Effect on Stability and Handling

2003-03-03
2003-01-0966
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.
Technical Paper

Requirements for Vehicle Dynamics Simulation Models

1994-03-01
940175
Computer simulation and real-time, interactive approaches for analysis, interactive driving simulation, and hardware-in-the-loop testing are finding increasing application in the research and development of advanced automotive concepts, highway design, etc. Vehicle dynamics models serve a variety of purposes in simulation. A model must have sufficient complexity for a given application but should not be overly complicated. In interactive driving simulation, vehicle dynamics models must provide appropriate computation for sensory feedback such as visual, motion, auditory, and proprioceptive cuing. In stability and handling simulations, various modes must be properly represented, including lateral/directional and longitudinal degrees of freedom. Limit performance effects of tire saturation that lead to plow out, spin out, and skidding require adequate tire force response models.
Technical Paper

Meeting Important Cuing Requirements with Modest, Real-Time, Interactive Driving Simulations

1994-03-01
940228
Interactive simulation requires providing appropriate sensory cuing and stimulus/response dynamics to the driver. Sensory feedback can include visual, auditory, motion, and proprioceptive cues. Stimulus/response dynamics involve reactions of the feedback cuing to driver control inputs including steering, throttle and brakes. The stimulus/response dynamics include both simulated vehicle dynamics, and the response dynamics of the simulation hardware including computer processing delays. Typically, simulation realism will increase with sensory fidelity and stimulus/response dynamics that are equivalent to real-world conditions (i.e. without excessive time delay or phase lag). This paper discusses requirements for sensory cuing and stimulus/response dynamics in real-time, interactive driving simulation, and describes a modest fixed-base (i.e. no motion) device designed with these considerations in mind.
Technical Paper

Validation of Ground Vehicle Computer Simulations Developed forDynamics Stability Analysis

1992-02-01
920054
This paper describes validation work carried out for two vehicle dynamics computer simulation programs. One program, referred to as VDANL (Vehicle Dynamics Analysis NonLinear), is intended to simulate passenger cars, vans and light trucks. The second program simulates All Terrain Vehicles (ATVs) and is referred to as NLATV (NonLinear ATV). The programs have been checked out and validated for a variety of maneuvering conditions and a broad range of vehicles. The programs run on IBM-PC/MS DOS compatible computers, and numerical methods have been used to give numerically stable solutions with reasonable computational speed over a broad range of maneuvering situations.
Technical Paper

A Human Factors Simulation Investigation of Driver Route Diversion and Alternate Route Selection Using In-Vehicle Navigation Systems

1991-10-01
912731
This paper describes a human factors simulation study of the decision making behavior of drivers attempting to avoid nonrecurring congestion by diverting to alternate routes with the aid of in-vehicle navigation systems. This study is the first phase of a two part project in which the second phase will apply the driver behavior data to a simulation model analysis of traffic flow. The object of the driver behavior experiment was to compare the effect of various experimental navigation systems on driver route diversion and alternate route selection. The experimental navigation system configurations included three map based systems with varying amounts of situation information and a non map based route guidance system. The overall study results indicated that navigation system characteristics can have a significant effect on driver diversion behavior, with better systems allowing more anticipation of traffic congestion.
Technical Paper

A Human Factors Study of Driver Reaction to In-Vehicle Navigation Systems

1991-08-01
911680
This paper describes a laboratory simulation study of driver reaction to in-vehicle navigation systems. The study included a pre-test questionnaire on demographic background and commuting behavior, simulation testing of navigation decision making, and a post-test questionnaire on navigation behavior and reactions to in-vehicle navigation systems and the laboratory simulation. A total of 277 subjects, both male and female, were employed over a wide range of ages. Test subjects were assigned to one of four navigation system groups or a no-system control group for the purpose of comparing system performance. The simulation task required subjects to experience a commuting ‘drive’ on a Southern California freeway route and minimize trip time by diverting off the main route to avoid congestion. Subjects were given orientation and training on the simulation and their navigation system condition, and were motivated by rewards and penalties to minimize trip time.
Technical Paper

Steady State and Transient Analysis of Ground Vehicle Handling

1987-02-23
870495
This paper presents simple linear and non-linear dynamic models and numerical procedures designed to permit efficient vehicle dynamics analysis on microcomputers. Vehicle dynamics are dominated by tire forces and their precursor input variables, and a few inertial and suspension properties. The steady state and dynamic models discussed herein include a comprehensive, unlimited maneuver tire model with relatively simple vehicle suspension kinematics and inertial dynamics to cover the full vehicle maneuvering range from straight running to combined limit cornering and braking or acceleration. An attempt was made to minimize the required tire and vehicle model parameter set and to include easily obtainable parameters. The computer analysis procedures include: A steady state model for determining perturbation side force coefficients, and a stability factor and maneuvering time constant for lateral/directional control.
Technical Paper

A Computer Simulation Analysis of Safety Critical Maneuvers for Assessing Ground Vehicle Dynamic Stability

1993-03-01
930760
Ground vehicle dynamic stability, including spinout and rollover, is highly dependent on maneuvering conditions and the nonlinear force response characteristics of tires. Depending on vehicle configuration, unstable behavior requires high, sustained lateral acceleration, and some maneuver induced excitation of the roll and yaw mode dynamics. Dynamic instability in some vehicles can be induced by a steering reversal maneuver that involves sustained limit performance lateral acceleration. Using a validated vehicle dynamics simulation, analysis is presented to illustrate what constitutes a critical stability sensitive maneuver. Two example test cases are used to show that a critical stability sensitive maneuver must be more severe than a single lane change. Even reaching tire saturation limits during an aggressive single lane change does not give the sustained lateral acceleration required to provoke instability conditions.
Technical Paper

The Use of Simulation in Truck Safety Research, Driver Training and Proficiency Testing

1990-10-01
902271
Real time man-in-the-loop simulation can be used in a variety of research, testing and training roles where safety, efficiency and/or economy are important. Simulation can allow complete control and uniformity over driving conditions and permit analysis of a range of vehicle and driver behavior variables. Simulation complexity and fidelity requirements will vary depending on application requirements. This paper reviews past and current driving simulation development efforts and applications. Simulation requirements are assessed relative to various applications, including vehicle handling, driver behavior, training, licensing and fitness for duty testing.
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