Exogenous feedback linearization of discrete-time systems

The goal of this paper is to introduce the notion of exogenous state feedback for discrete-time systems. It is shown that a discrete-time system may be linearizable by exogenous feedback, even if it can not be linearized by endogenous feedback. This property was completely unexpected and constitutes a fundamental difference with respect to the continuous-time case. The theory is illustrated through an example whose structure is similar to the exact discrete-time model of a mobile robot, showing that the above mentioned property concerns not only academic examples, but physical systems as well.