Mechanical System Simulation (MSS) is the technology used to analyze systems undergoing large overall motion, such as an automobile going over a pothole or a space shuttle performing satellite retrieval. MSS formulations lead to a coupled set of Differential and Algebraic Equations called Index-3 DAE. Index reduction methods (IRM) are employed to simplify and solve these equations. Three factors determine the accuracy and stability of solutions for mechanical systems: (1) the System States selected, (2) the IRM used, and (3) the numerical integrator used. Ideally, these selections should be problem driven.Yet, most Commercial MSS software apply very limited combinations of the above to all problems. This limitation is being addressed by developing a library of IRM and integrators, and allowing for their independent selection. Researchers are enhancing an Augmented Lagrangian Formulation, an IRM, to control constraint violation (ALF-CC), implement it, and demonstrate its effectiveness with two integrators. ALF-CC is very accurate and fast and promises to solve through singular configurations, accommodate inequality constraints, and system topology changes. ALF-CC is being compared to other methods.Commercial Applications:The developed methods will be implemented in ADAMS, a Commercial MSS product. All users of ADAMS will benefit by tailoring the numerical simulation to the problem being solved. A larger class of problems can be effectively analyzed. Robust numerical methods developed in this project will help us sell effectively to a much larger market of lesser experienced users. Problem specific simulators may be developed.
