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The (Vehicle Inertia Parameter Evaluation Rig) VIPER II is a full vehicle mass and inertia parameter measurement machine. The VIPER II expands upon the capabilities of its predecessor and is capable of measuring vehicles with a mass of up to 45,360 kg (100,000 lb), an increase in capacity of 18,100 kg (40,000 lb). The VIPER II also exceeds its predecessor in both the length and width of vehicles it can measure. The VIPER II's maximum vehicle width is 381 cm (150 in) an increase of 76 cm (30 in) and maximum distance from the vehicle CG to the outer most axle is 648 cm (255 in) an additional 152 cm (60 in) The VIPER II is capable of performing measurements including vehicle CG height, pitch, roll, and yaw moments of inertia and the roll/yaw cross product of inertia. While being able to measure both heavier and larger vehicles, the VIPER II is designed to maintain a maximum error of 3% for all inertia measurements and 1% for CG height.

This paper describes the mechanical design of a Suspension Parameter Identification Device and Evaluation Rig (SPIDER) for wheeled military vehicles. This is a facility used to measure quasi-static suspension and steering system properties as well as tire vertical static stiffness. The machine operates by holding the vehicle body nominally fixed while hydraulic cylinders move an “axle frame” in bounce or roll under each axle being tested. The axle frame holds wheel pads (representing the ground plane) for each wheel. Specific design considerations are presented on the wheel pads and the measurement system used to measure wheel center motion. The constraints on the axle frames are in the form of a simple mechanism that allows roll and bounce motion while constraining all other motions. An overview of the design is presented along with typical results.

This research was performed using a designed experiment to evaluate the loss of dry surface braking performance and stability that could be associated with the disablement of specific brake positions on a tractor-semitrailer. The experiment was intended to supplement and update previous research by Heusser, Radlinski, Flick, and others. It also sought to establish reasonable limits for engineering estimates on stopping performance degradation attributable to partial or complete brake failure of individual S-cam air brakes on a class 8 truck. Stopping tests were conducted from 30 mph and 60 mph, with the combination loaded to GCW (80,000 lb.), half-payload, and with the flatbed semitrailer unladen. Both tractor and semitrailer were equipped with antilock brakes. Along with stopping distance, brake pressures, longitudinal acceleration, road wheel speed, and steering wheel position and effort were also recorded.

Automating road vehicle control can increase the range and reliability of dynamic testing. Some tests, for instance, specify precise steering inputs which human test drivers are only able to approximate, adding uncertainty to the test results. An automated steering system has been developed which is capable of removing these limitations. This system enables any production car or light truck to follow a user-defined path, using global position feedback, or to perform specific steering sequences with excellent repeatability. The system adapts itself to a given vehicle s handling characteristics, and it can be installed and uninstalled quickly without damage or permanent modification to the vehicle.

Many vehicle-to-pole impacts occur when a vehicle leaves the roadway due to oversteer and loss of control in a lateral steering maneuver. Such a loss of control typically results in the vehicle having a significant component of lateral sliding motion as it crosses the road edge, so that impacts with objects off of the roadway often occur to the side of the vehicle. The response of the vehicle to this impact depends on the characteristics of the impacted object, the characteristics of the vehicle in the impacted zone, and the speed and orientation of the vehicle. In situations where the suspension or other stiff portions of a vehicle contacts a wooden pole, it is not uncommon for the pole to fracture. When this occurs, reconstruction of the accident is complicated by the need to evaluate both the energy absorbed by the vehicle as well as the energy absorbed by the pole.

This paper presents the implementation and performance of an electric all-wheel drive system on a series-parallel, through-the-road hybrid electric vehicle. Conventional methods of all-wheel drive do not provide a suitable solution for this type of vehicle as the powertrain lacks a mechanical link between the front and rear axles. Moreover, this unique architecture allows the vehicle to be propelled solely by the front, or the rear, wheels during typical operation. Thus, the algorithm presented here manages wheel slip by either the front, or rear wheels when engaging to provide all-wheel drive capability. necessary testing validates the robustness of this Extensive system.

During Phase VI of the National Highway Traffic Safety Administration's (NHTSA) Light Vehicle Rollover Research Program, three of the twenty-six light vehicles tested exhibited significant response asymmetries with respect to left versus right steer maneuvers. This paper investigates possible vehicle asymmetric characteristics and unintended inputs that may cause vehicle asymmetric response. An analysis of the field test data, results from suspension and steering parameter measurements, and a summary of a computer simulation study are also given.

This paper introduces a new series of empirical mathematical models developed to characterize brake torque generation of pneumatically actuated Class-8 vehicle brakes. The brake torque models, presented as functions of brake chamber pressure and application speed, accurately simulate steer axle, drive axle, and trailer tandem brakes, as well as air disc brakes (ADB). The contemporary data that support this research were collected using an industry standard inertia-type brake dynamometer, routinely used for verification of FMVSS 121 commercial vehicle brake standards.

With the goal of improving the driver's steering performance, the four(all) wheel steering(4WS) system was designed, and theoretical and experimental analysis of the 4WS system was investigated. In the 4WS system the low speed maneuverability is better due to a smaller turning radius. In reality, however, the opposite steering of the rear wheels could be counter-productive for certain maneuvers as shown in the Fig.1. In this paper, this counter-productivity is called the parking problem. The objective of this study is to prevent the parking problem and to maintain the maneuverability of the 4WS vehicle. To accomplish this goal, a new concept of the 4WS system for the low speed range has been introduced.

The Suspension Parameter Measurement Device Model 7547 (SPMD Model 7547) has been designed and built for the purpose of measuring displacements and forces acting on the road wheels of a vehicle. These displacements and forces may be due to movement of the vehicle body (kinematic), forces occurring in the plane of the road (compliance), or due to movement of the steering wheel (steering). The SPMD Model 7547 tests the entire vehicle as a unit and provides a “black box” determination of the suspension characteristics in terms of input/output relationships. This data can then be used in the simulation of the performance of light cars and trucks.

The purpose of this paper is to give a description of using the new type Suspension Parameter Measurement Device. The design philosophy and specifications are elaborated on in another SAE paper entitled “Design of a New-Type Suspension Parameter Measurement Device”. The importance of using this new machine will be addressed in this paper. Because of the ease of use for this new device, testing can be accomplished in hours. To check repeatability, repeat testing can be done in a short period of time. This rapid testing is the main advantage of the new generation of SPMD's. The new SPMD collects raw data from transducers. All data are stored in the computer. Some are used directly to generate graphic outputs. Some are utilized to calculate wanted parameters. Graphs are generated so that some characteristics can be scrutinized. Parameters can be presented either by points or by cross plotting in graphs.

Multi-body simulations are very powerful tools in the modeling of dynamic mechanical systems. This study uses the multi-body simulation program ADAMS to analyze a light vehicle suspension. The paper introduces ADAMS modeling concepts and then applies them in a case study examining the effects of additional longitudinal compliance on the ride and handling behavior of a 1/4 car suspension model. The results were a marginal increase in the lateral stiffness of the vehicle, approximately the same ride performance, and an increase in the compliance steering angle.

This paper presents an evaluation of a vehicle dynamics model intended to be used for the National Advanced Driving Simulator (NADS). Dynamic validation for high performance simulation is not merely a comparison between experimental and simulation plots. It involves strong insight of vehicle's subsystems mechanics, limitations of the mathematical formulations, and experimental predictions. Lateral, longitudinal, and ride dynamics are evaluated using field test data, and analytical diagnostics. The evaluation includes linear and non-linear range of vehicle dynamics response.

The discernment of whether a tire mark on a roadway is the result of a skidding tire or is the result of the rotation of the vehicle with unlocked wheels is important in vehicular accident reconstruction analysis. Resolution of the tire marks left by a vehicle after skidding and/or yawing on dry asphalt were experimentally studied for their similarities and differences under controlled test conditions. This paper analyses the results of this study and shows pictorially the differences for use by the accident reconstructionist. Analytical discussion are also presented that illustrate speed determination as estimated from yaw markings on the roadway.

This paper is primarily a printed listing of the National Highway Traffic Safety Administration’s (NHTSA) Light Vehicle Inertial Parameter Database. This database contains measured vehicle inertial parameters from SAE Paper 930897, “Measured Vehicle Inertial Parameters -NHTSA’s Data Through September 1992” (1), as well as parameters obtained by NHTSA since 1992. The proceeding paper contained 414 entries. This paper contains 82 new entries, for a total of 496. The majority of the entries contain complete vehicle inertial parameters, some of the entries contain tilt table results only, and some entries contain both inertia and tilt table results. This paper provides a brief discussion of the accuracy of inertial measurements. Also included are selected graphs of quantities listed in the database for some of the 1998 model year vehicles tested.

This paper is a printed listing of public domain vehicle center-of-gravity (CG) location measurements conducted on behalf of the National Highway Traffic Safety Administration (NHTSA). This paper is an extension of the 1999 SAE paper titled “Measured Vehicle Inertia Parameters - NHTSA's Data Through November 1998” ( 1 ). The previous paper contained data for 496 vehicles. This paper includes data for 528 additional vehicles tested as part of NHTSA's New Car Assessment Program (NCAP) for year 2001 through year 2008 ( 2 , 3 , 4 , 5 , 6 , 7 , 8 , 9 ). The previous data included center-of-gravity location and mass moments-of-inertia for nearly all of the entries. The NCAP involves only the CG location measurements; so the vehicles listed in this paper do not have inertia data. This paper provides a brief discussion of the entries provided in the tabular listings as well as the accuracy of CG height measurements.

This paper presents the methodology of the investigative techniques for examining vehicular fires. Discussion illustrating the mechanical “finger prints” that show the investigating team the mechanism of fire spread is presented. The common causes of vehicular fires and examples of each are discussed. The techniques used by the forensic chemist in determining incendiary fires and the use of specialized equipment in the investigation are illustrated. Tests are discussed to show the theories postulated in the investigative stages of the vehicle examination. Lastly, the interdisciplinary team approach to the investigation is discussed showing the validity of “forensic” engineering and chemistry in examining vehicle fires.