Antiwindup Input–Output Linearization Strategy for the Control of a Multistage Continuous Fermenter With Input Constraints

This paper deals with the control of a multistage continuous fermenter (MSCF) used for the study of wine fermentation. The control design is facing three main difficulties: 1) system nonlinearity; 2) lack of online measurement of the controlled variable (sugar concentration); and 3) positive constraints on the control inputs (inlet flow rates of each tank) coming from the cascade structure of the system. A control strategy has been proposed, which accounts for these specificities. It is based on an input-output linearization control law coupled with an antiwindup technique and a state observer (the Kalman filter). The strategy has been tested and validated first on numerical simulations and then applied to the real process. The experiments gave satisfactory results that open up new perspectives on the use of the MSCF.