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The dynamic performance of a multi-wheeled combat vehicle developed in a multi-body dynamics code initially on the basis of design information was compared, calibrated and validated in a systematic three-stage process against measured data obtained on US Army Aberdeen Test Center (ATC) test courses. In the comparison stage the model was refined using insights gained from the live vehicle tests. At that point, the model was adjusted or calibrated using optimization software. The process of optimization required judicious choice of performance parameters suited to the particular test event referencing a test course or maneuver. As an example, the vehicle roll, pitch and yaw rates were used to characterize the vehicle for the J-turns, whereas statistical moments of the vertical acceleration were selected to describe the vehicle performance on the 6-inch Washboard.

Experimental analysis of human motion has been based on optical, magnetic, or electronic tracking techniques to determine body segment locations and orientations. The Average Coordinate Reference System (ACRS) method was developed to reduce experimental errors in human locomotion analysis. Experimentally measured kinematic data is used to conduct analysis in human modeling, and the model accuracy is directly related to the accuracy of the data. However, the accuracy is questionable due to skin movement, deformation of skeletal structure while in motion and limitations of commercial motion analysis systems. In this study, the ACRS method is applied to an optically-tracked segment marker system, although it can be applied to many of the others as well. Many previous studies adopted redundant marker systems, using four or five optical markers, instead of the basic three marker system to provide statistically better results of body segment position and orientation.

The purpose of this study is to improve predicted tire forces for vehicle simulations on off-road terrain and for simulations incorporating terrain features such as curbs, pavement markers or potholes. The model presented in this paper describes the longitudinal behavior of the tire for traversing high-fidelity terrain profiles. An extended rolling radial-interradial tire model is used to estimate the pressure distribution of the tire contact patch, while a tangential spring model of the tire carcass is used to estimate tractive forces at the tire/road interface. Due to the complexity of the model real-time simulation is not possible, however it is useful for off-line simulations incorporating rough terrain or short-wavelength terrain features.