Computation of flat outputs for discrete-time nonlinear systems with mathematica

The paper describes the first attempt to develop the software for computing the so-called flat output of the discrete-time nonlinear control system. The functions are implemented in NLControl, a package for nonlinear control systems, developed within the computer algebra system Mathematica. The implemented algorithm is quite elaborate. It involves the elements from the exterior differential calculus and from the theory of non-commutative polynomial rings, and requires solving large-scale systems of partial differential equations. At present the developed programs are only able to handle simple systems.