20-sim software for hierarchical bond-graph/block-diagram models

We discuss the modeling and simulation package 20-sim, a tool for modeling and simulation of dynamic behavior of engineering systems. Engineering systems as application domain means that we focus on systems that span multiple physical domains and the information domain. The 20-sim software is an interactive tool, where model entry and model processing are fully integrated. This means that already during model entry and editing, models can be checked on their consistency. 20-sim has its own simulator, using sophisticated numerical integration methods, taken from. internationally accepted numerical libraries. The use of 20-sim is demonstrated by an example, in which a 3-dof scara robot with controller is modeled and simulated.