HyBrSim – A Modeling and Simulation Environment for Hybrid Bond Graphs

Bond graphs are a powerful formalism to model continuous dynamics of physical systems. Hybrid bond graphs introduce an ideal switching element, the controlled junction, to approximate continuous behavior that is too complex for numerical analysis (e.g., because of nonlinearities or steep gradients). HyBrSim is a tool for hybrid bond graph modeling and simulation implemented in Java and documented in this paper. It performs event detection and location based on a bisectional search, handles run-time causality changes, including derivative causality, performs physically consistent (re-)initialization, and supports two types of event iteration because of dynamic coupling. It exports hybrid bond graph models in Java and C/C++ code that includes discontinuities as switched equations (i.e., pre-enumeration is not required).