The use of symbolic algebra in control

This paper will present several tools for model manipulation, model-order reduction, analysis, and the design/synthesis of control systems, developed in the symbolic algebra environment Mathematica. New control objects have been introduced in the framework of Mathematica´s Control System Professional package, with several new associated transformations and model format manipulations. A new model-order reduction method called the quasi-generalised singular perturbation method has been implemented, and some interesting observations on appropriate pole assignment algorithms for use with systems containing symbols are reported. Some recent results on the robust diagonal dominance of uncertain multivariable systems, and the prediction of limit cycles in uncertain non-linear systems are considered.