Input constrained funnel control with applications to chemical reactor models

Error feedback control (in the presence of input constraints) is considered for a class of exothermic chemical reactor models. The primary control objective is regulation of a setpoint temperature T∗ with prescribed accuracy: given ¿ 0 (arbitrarily small), ensure that, for every admissible system and reference setpoint, the regulation error e = T − T∗ is ultimately smaller than (that is, ‖e(t)‖¡ for all t su4ciently large). The second objective is guaranteed transient performance: the evolution of the regulation error should be contained in a prescribed performance funnel F around the setpoint temperature T∗. A simple error feedback control with input constraints of the form u(t)=sat[u; 6 u](−k(t)[T (t)−T∗]+ u∗), u∗ an o9set, is introduced which achieves the objective in the presence of disturbances corrupting the measurement. The gain k(t) is a function of the error e(t) = T (t) − T∗ and its distance to the funnel boundary. The input constraints u; 6 u have to satisfy certain feasibility assumptions in terms of the model data and the operating point T∗. c © 2004 Elsevier B.V. All rights reserved.