Real-Time Dynamics Simulation — A Design Optimization Tool 880883

Recent developments in multibody dynamic formulations that lead to inherently high speed simulation and, more important, to implementation on emergining high speed parallel processing computer architectures are presented and their use as a tool for dynamic system design optimization is outlined.

A recursive formulation of equations of motion for vehicle system dynamics are summarized, with reference to detailed derivations cited. Application of the method is made to the Army's High Mobility Multipurpose Wheeled Vehicle (HMMWV), an off-road vehicle with four independent double A-arm suspension subsystems. It is shown that graph theoretic models of the mechanical system lead directly to definition of concurrent computations that permit exploitation of emerging low cost, high speed parallel processing simulation hardware. A network computing implementation of the dynamiçs algorithm on an Alliant FX 8 parallel processor, using the Network Computing System and a high speed graphics workstation is outlined. This implementation demonstrates feasibility of dynamic simulation of the mechanical system at 70 time steps per second and transfer of state information to the graphics workstation to create an animation as the simulation is being carried out; hence real-time simulation. Application of this qualitatively new technology is discussed for real-time man-in-the-loop simulation in support of vehicle and other mechanical system design applications.

A design system; using parallel processors, network computing, and high speed graphics subsystems; is described that permits the engineer to modify design parameters and immediately obtain an animation of dynamic performance of the system. This new capability provides a tool that experienced engineers can use effectively to develop a qualitative and quantitative understanding of the dependence of dynamic on design parameters.