Complex engineering systems such as automobiles are often relieved by a modular approach for modeling and simulation to make it treatable by a team of engineers. The functional decomposition is due to different engineering disciplines and engineering intuition.
The resulting subsystems are considered as dynamic blocks with inputs and outputs. The global system structure is given by interconnections of inputs and outputs of corresponding blocks. Since the global system structure is independent of the internal subsystem description this procedure allows for independent and parallel modeling of the internal dynamics of each block. Although this approach is widely used in control theory and also more and more in mechatronics, the mechanical parts are traditionally modeled as one multibody system.
In this paper a modular formulation of multibody systems is proposed which is based on the block representation of a multibody system with corresponding input and output quantities. Multibody system blocks can be connected by means of arbitrary joints and coupling elements resulting in a global system with high degree of modularity in the modeling procedure. The option to use different simulation tools for modular simulation of the global system behavior has the potential to even more exploit the modular system structure.