Multibody Systems in Technical Mechanics

The dynamics of multibody systems (MBS) is a focal point of multi-body modeling in mechanical engineering. Its central role was emphasized by the research program „Dynamik von Mehrkörpersystemen“ of the Deutsche Forschungsgemeinschaft (DFG). Within this research program, the goal of the MBSSIM project was to develop integrators for the differential-algebraic equations (DAE) of MBS in descriptor form as opposed to the traditional approach of treating MBS in minimal form for which standard ODE integrators had been used for a long time. The main motivation for the project at the outset was the potential presented by the straightforward inclusion of kinematic loops as well as the easy coupling of subsystems in descriptor models contrary to the situation with minimal models. Before we explain these types of equations and their derivation in more detail, we will first put the multibody system approach in perspective within the general framework of mechanical engineering and then describe in broad terms what this approach consists of as well as what the typical engineering problems in this area are. Having derived the equations of motion (EOM), we will highlight some practical aspects of modeling and simulation of MBS. As we do so, we will make a new contribution to the modeling of MBS in natural coordinates which further enhances the structures in such models.