ABSTRACT
The pattern of these equations, which is used for all simulations, is to write a statement (ACSL uses the FORTRAN language) for the highest derivative of each of the unknowns, and then numerically integrate to get the lower derivatives and finally the unknown itself. For each variable we make up convenient names such as XlDOT2
Statements which specify how long the problem is to run, what kind of integrator to use, the size of the time step, which variables are to be graphed or tabulated, the format of tables and graphs, etc. allow us to conveniently control our simulation. While writing and running a command-line program like our example would certainly not be difficult or time consuming, if we have available GUI-type software, it would probably be preferred by most users for such simple problems. Since the MA TLAB/SIMULINK software of this type is available to me, I have used it earlier in this text and will now explain its use in more general terms. Learning to use this specific software will really give you good preparation for using any dynamic-system simulation software.
