Design of Robust Input-Constrained Feedback Controllers for Nonlinear Systems

This work contributes to the optimal design of closed-loop nonlinear systems with input saturation in the presence of unknown uncertainty. Stability conditions based on contractive constraints were developed for a general class of nonlinear systems under some Lipschitz assumptions. Closed-loop robust stability and robustly optimal performance can be guaranteed in the presence of input bounds, if the solution of the design problem, formulated as a nonlinear semi-infinite program (SIP) with differential equation constraints, can be guaranteed to be feasible. In this work, the SIP is solved by means of a local reduction approach, which requires a local representation of the so-called lower level problems associated with the SIP. The suggested design method is illustrated by means of chemical reactor control problem. (C) 2018, IFAC (International Federation of Automatic Control) Hosting by Elsevier Ltd. All rights reserved.