next up previous
Next: 3.1 The Nature and Up: Analyzing Discontinuities in Physical Previous: 2.2 Mode Switching in

3 Analyzing Model Discontinuities

 

Since one discontinuous change may cause a sequence of mythical changes, what is the guarantee that simulation with a system model will not produce an infinite loop of mythical mode changes? This can happen if a mythical mode loops back to a mythical mode that has already appeared in the sequence of mode changes. Discontinuous changes are modeled to be instantaneous, and the occurrence of a loop during mythical mode changes would imply that system behavior does not progress over time. This violates physical reality because all dynamic physical systems have to satisfy divergence of time[6]. In such situations, the system model is incorrect and needs to be modified to generate correct system behaviors.

Our methodology for analyzing the consistency of a sequence of switches is based on applying the principle of invariance of state to the MMA. This defines a multiple energy phase space analysis scheme to determine the physical consistency of hybrid models. The initial values of energy storing elements in the new real mode are determined by the principle of conservation of state.





Pieter J. Mosterman
Mon Jul 21 19:58:19 CDT 1997