Flatness-based control of nonlinear delay systems: a chemical reactor example

A trajectory tracking control method for a class of non-linear systems with time delays is proposed. For this, the new concept of delta-flatness is introduced, which is an extension of the notions of flatness for non-linear systems and delta-freeness for linear delay systems. A two-step design procedure is derived. It splits into trajectory design, which directly provides an open-loop tracking controller, and stabilization around the reference trajectory. This feedback stabilization is based on a state prediction, leading to a discrete time controller.