On state-event constructs in physical system dynamics modeling

In this paper it will be shown that a common modeling approach based on extrapolation from standard (textbook) models may lead to the unnecessary use of the state-event construct. Although this may be hand-waved as the result of bad modeling practice, the running example discussed herein has been used for quite some time as a benchmark problem for event handling in the literature [F. Breitenecker, ‘Comparison 7: Constrained pendulum’, Simulation News Europe, No. 7, p. 29, March 1993, ARGESIM, Vienna University of Technology, Vienna, Austria (the benchmark proposed herein was used in several later issues of this journal)]. Unnecessary use of the state-event construct may be prevented by using a model representation that increases insight in the physical meaning of the state variables used in the model and in the way they are handled. Herein the mentioned benchmark problem is analyzed in order to demonstrate the problem and some guidelines are given which may increase this insight.