Modeling multidisciplinary systems with Hybrid Statecharts

Some of the problems when modelling and/or simulating multidisciplinary systems, in today´s engineering systems, result from the different time scales of the involved components. Often, the behaviour of fast components may be modeled with instantaneous changes, thus reducing the stiffness of the equations to be solved numerically. This approach leads to a variable structure of a DAE system of equations which is, basically, a hybrid DAE. This representation, being a low level formalism, is not intuitive when extracting the fundamentals of the system´s behaviour. The Hybrid Statecharts, being a graphical formalism, is an interesting way to increase the legibility of hybrid DAEs. This paper explores the Hybrid Statecharts formalism in order to represent continuous and discrete behaviour in the engineering field. The Statecharts hierarchy mechanism, implemented by means of state decomposition, is important to address the modelling of complex hybrid behaviour, as is normally the case with multidisciplinary systems.