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This paper discusses the development of a 1994 Ford Taurus vehicle model for the National Advanced Driving Simulator's planned vehicle dynamics simulation, NADSdyna. The front and rear suspensions of the Taurus are modeled using recursive rigid body dynamics formulations. To complement vehicle dynamics, subsystems models that include steering, braking, and tire forces are included. These models provide state-of-the-art high fidelity vehicle handling dynamics for real-time simulation. The realism of a particular formulation depend heavily on how the parameters are obtained from the physical system. Therefore, the development of a data set for a particular model is as important as the model itself. The methodology for generating the Taurus data set is presented. The power train model is not yet included, so the simulation is run with the vehicle either at constant speed or decelerating.

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 National Highway Traffic Safety Administration's Vehicle Research and Test Center (VRTC) plans to evolve the state-of-the-art of steering system modeling for driving simulators with the ultimate goal being the development of a high fidelity steering feel model for the National Advanced Driving Simulator (NADS). The VRTC plans on developing reliable research tools that can be used to determine the necessary features for a steering model that will provide good objective and subjective steering feel. This paper reviews past and continuing work conducted at the VRTC and provides a plan for future work that will achieve this goal.

This paper presents an overview of work performed by the National Highway Traffic Safety Administration's (NHTSA) Vehicle Research and Test Center (VRTC) to test, validate, and improve the planned National Advanced Driving Simulator's (NADS) vehicle dynamics simulation. This vehicle dynamics simulation, called NADSdyna, was developed by the University of Iowa's Center for Computer-Aided Design (CCAD) NADSdyna is based upon CCAD's general purpose, real-time, multi-body dynamics software, referred to as the Real-Time Recursive Dynamics (RTRD), supplemented by vehicle dynamics specific submodules VRTC has “beta tested” NADSdyna, making certain that the software both works as computer code and that it correctly models vehicle dynamics. This paper gives an overview of VRTC's beta test work with NADSdyna. The paper explains the methodology used by VRTC to validate NADSdyna.

According to NHTSA's 2011 Traffic Safety Facts [1], passenger vehicle occupant fatalities continued the strong decline that has been occurring recently. In 2011, there were 21,253 passenger vehicles fatalities compared to 22,273 in 2010, and that was a 4.6% decrease. However; large-truck occupant fatalities increased from 530 in 2010 to 635 in 2011, which is a 20% increase. This was a second consecutive year in which large truck fatalities have increased (9% increase from 2009 to 2010). There was also a 15% increase in large truck occupant injuries from 2010. Moreover, the fatal crashes involving large trucks increased by 1.9%, in contrast to other-vehicle-occupant fatalities that declined by 3.6% from 2010. The 2010 accident statistics NHTSA's report reveals that large trucks have a fatal accident involvement rate of 1.22 vehicles per 100 million vehicle miles traveled compared to 1.53 for light trucks and 1.18 for passenger cars.

The intent of this research is to understand the effects worn dampers have on vehicle stability and safety through dynamic model simulation. Dampers, an integral component of a vehicle's suspension system, play an important role in isolating road disturbances from the driver by controlling the motions of the sprung and unsprung masses. This paper will show that a decrease in damping leads to excessive body motions and a potentially unstable vehicle. The concept of poor damping affecting vehicle stability is well established through linear models. The next step is to extend this concept for non-linear models. This is accomplished through creating a vehicle simulation model and executing several driving maneuvers with various damper characteristics. The damper models used in this study are based on splines representing peak force versus velocity relationships.

An existing tire model was investigated for additional normal load-dependent characteristics to improve the large truck simulations developed by the National Highway Traffic Safety Administration (NHTSA) for the National Advanced Driving Simulator (NADS). Of the existing tire model coefficients, plysteer, lateral friction decay, aligning torque stiffness and normalized longitudinal stiffness were investigated. The findings of the investigation led to improvements in the tire model. The improved model was then applied to TruckSim to compare with the TruckSim table lookup tire model and test data. Additionally, speed-dependent properties for the NADS tire model were investigated (using data from a light truck tire).

This paper presents the results of a design space exploration based on the simulations of the MTV (Medium Tactical Vehicle) 5.0 Ton Cargo Truck using MSC-ADAMS (Automatic Dynamic Analysis of Mechanical System). Design space study is conducted using ADAMS/Car and ADAMS/Insight to consider parametric design changes in suspension and the tires of the cargo truck. The methodology uses an industry acknowledged multibody dynamics simulation software (ADAMS) for the modeling of the cargo truck and a flexible optimization architecture to explore the design space. This research is a part of the work done for the U.S. Army TACOM (Tank Automotive and Armaments Command) at the Center for Automotive Research, The Ohio State University.

The severity of an impact in terms of the acceleration in the occupant compartment is dependent not only on the change in vehicle velocity, but also the time for the change in velocity to occur. These depend on the geometry and stiffness of both the striking vehicle and struck object. In narrow-object frontal impacts, impact location can affect the shape and duration of the acceleration pulse that reaches the occupant compartment. In this paper, the frontal impact response of a full-sized pickup to 10 mile per hour and 20 mile per hour pole impacts at the centerline and at a location nearer the frame rails is compared using the acceleration pulse shape, the average acceleration in the occupant compartment, and the residual crush. A bilinear curve relating impact speed to residual crush is developed.

This paper describes an adaptive control strategy for improving the steering response of an automated vehicle steering controller. In order to achieve repeatable dynamic test results, precise steering inputs are necessary. This strategy provides the controller tuning parameters optimized for a particular vehicle's steering system. Having the capability to adaptively tune the steering controller for any vehicle installation provides an easy method for obtaining precise steering inputs for a wide range of vehicles, from small off-road utility vehicles to passenger vehicles to heavy trucks. The S.E.A. Ltd. Automated Steering Controller (ASC) is used exclusively in conducting this research. By recording the torque input to the steering system by the steering controller and the resulting steering angle during only a single test, the ASC is able to characterize the steering system of the test vehicle and create a computer model with appropriate parameters.

This paper discusses the improvement of a heavy truck anti-lock brake system (ABS) model currently used by the National Highway Traffic Safety Administration (NHTSA) in conjunction with multibody vehicle dynamics software. Accurate modeling of this complex system is paramount in predicting real-world dynamics, and significant improvements in model accuracy are now possible due to recent access to ABS system data during on-track experimental testing. This paper focuses on improving an existing ABS model to accurately simulate braking under limit braking maneuvers on high and low-coefficient surfaces. To accomplish this, an ABS controller model with slip ratio and wheel acceleration thresholds was developed to handle these scenarios. The model was verified through testing of a Class VIII 6×4 straight truck. The Simulink brake system and ABS model both run simultaneously with TruckSim, with the initialization and results being acquired through Matlab.

The development of injury predictive models for pedestrian thoracic impact based on experimental data obtained in a previous study is presented. The data consists of ten cadaveric test subjects including eight side and two frontal impacts. A ten accelerometer array was mounted on the thorax to define thoracic kinematics. Three types of parameters, Q, B, and PSD, are developed to summarize each acceleration signal. A statistical regression is performed to generate empirical models for predicting the injury level (number of rib fractures) from these parameters. Coefficients of determination for these models range from 0.8 to 0.99 with the new PSD parameter showing exciting promise. Success of these parameters in predicting thoracic injury implies a relationship with frequency, particularly in the neighborhood of 60 Hz.

This paper presents the analytical results of two different computer simulations of the vehicle pedestrian impact; PROMETHEUS 2 and the MacLaughlin/Daniel (MACDAN) models. The results presented illustrate the simularity and differences between the two models and accuracy of both to predict the actual occurrance. Also presented is a discussion relative to the modeling techniques of obtaining data for the pedestrian. This presentation illustrates the scaling techniques and actual data obtained in order to accurately simulate the pedestrian.

This paper presents an interactive computer simulation of the pedestrian/vehicle interface. The simulation presents the results in an easy to analyze format including animation of the whole event. User requests for specific output data is available via a graphic menu. The model employs the use of the MacLaughlin/Daniel Computer Simulation developed by the National Highway Traffic Safety Administration. To illustrate the usefulness of the graphical and pictorial output, the results of a pedestrian/vehicle impact are presented.

Two computer models, ABAG 19 and HSRI-3D, were validated against experimental data to determine and compare their capability for simulating the responses of air bag restrained automobile occupants in severe frontal collisions. Standard sets of model input parameters were developed for both driver and passenger. The primary objective was to determine which model was best suited for determining potential crashworthiness in a large number of production vehicles. Advantages and disadvantages of the models were determined, using criteria such as accuracy, ease of use, quality of documentation and user orientation.

Accident reconstruction encompasses the evaluation of a crash situation from evidence and observations available after the accident. Such evidence includes vehicular damage, property damage, marks, and witness statements. The reconstructionist is responsible for transforming this information into a theory of the accident sequence. In addition to satisfying the evidence and statements, the theory must also agree with the laws of physics which dictate reactions to forces and torques. The computer program presented here assists in this analysis by providing a graphical depiction of the accident scenario. This program is called ANMATE and utilizes simulation results prepared by the CRASH or SMAC program for vehicle motions. A number of features assist in viewing the accident from different points of view, allow the user to stop action, and provide other data presentation formats. A real world example is given.

The objective of this paper is to develop a self-tuning optimal control of an active suspension. An active suspension composed of an identifier and a controller is proposed in this paper. Although control strategies on active (or semi-active) suspensions have been investigated during the past few decades, some problems are not well understood yet. One of them arising from the ride control of an active suspension is that when the weight and the moments of inertia of the sprung mass are varied, the feedback gains of the controller should vary with the variation of parameters accordingly. Therefore, the identifier is proposed before the controller is designed. In the real situations, the parameter variation may occur when loadings on vehicles vary - either from passengers or payloads, especially, in the case of loading on a truck. An identification structure using parallel model reference adaptive system (MRAS) is proposed to identify the true parameters.

The objective of this paper is to investigate the effect of padding on the human thorax. Different types of padding are used in the computer simulations. Lumped models are developed to perform the simulations. Through the responses of the simulations one can determine what kind of padding is desired. This paper provides the first phase of using a computer-aided tool. Though much attention has been paid to either the investigation of padding or human thorax modelling, how the physical properties of padding affect thoracic protection is not well known. The combination of padding and the thorax needs a lot of effort to unveil their relationship. This paper attempts to provide the guideline of what a good padding material should be. The determination of an optimal padding is one of the goals in this study. Hopefully, the results of this paper can make a contribution to the vehicle safety design, especially the car door.

This paper describes the development of a free-motion headform which was designed to permit the simulation of head impacts common in the automotive crash environment. A Hybrid III headform was modified allowing it to be propelled in free flight at up to 64.4 km/h velocities. The headform was also instrumented with a nine-accelerometer array to permit the calculation of rotational accelerations. Tests were conducted to determine the repeatability and sensitivity of the device, and component test results were compared with results from a full scale crash test in which Hybrid III dummies were used. Comparisons are also made with accident investigation information obtained from the NHTSA Washington Hospital Trauma Center study.