Challenges when Creating Variable-structure Models.

Variable-structure models can switch their system of equations during a simulation, allowing for a change of level of detail or behavior. The need for this kind of models has been well-established, and there are simulation environments that can handle them. While most research papers on this topic focus on language and tool issues regarding variable-structure models, in this paper, we will shed some light on the pragmatics of actually creating such a model in a reusable way. During the construction of a variable-structure model, the modeler will face several challenges, such as the initialization of new modes during mode switches. We will collect and discuss the most important challenges and, if possible, provide rules of thumb on how to handle these challenges appropriately.