Nonlinear controllers design for robust stabilization of continuous biological reactors

A simple output feedback design for nonlinear biological reactors is presented. Intrinsic nonlinear behaviour, lack of measurements and large model uncertainties render this class of processes difficult to control. In this work, it is shown that an output feedback proportional+integral (PI) control law is able to cope with input constraints and requires only a very limited knowledge of the process parameters. The performance of the control law is demonstrated by applications to a wastewater treatment plant with numerical simulations