On the design of approximate non-linear parametric controllers

This paper focuses on the design of non-linear parametric controllers, arou nd a nominal input/output trajectory of a discrete-time non-linear system. The main result provided herein is a relationship between the tracking perf ormance of he closed-loop control system in the neighbourhood of a nominal trajectory, and some local features (the first-order linear approximations about the nominal trajectory) of the non-linear mappings which characterize the plant and the feedback controller. Such a result can be used to predic t the dynamic behaviour of the control system, and to reduce the computatio nal complexity of the optimization task associated with the tuning of the p arametric feedback controller. Copyright (C) 2000 John Wiley & Sons, Ltd.