Robust pole placement control of a fermentor

Abstract

This paper deals with robust pole placement control of a continuous flow alcoholic fermention process. The strain used for experiments is Saccharomyces cerevisae UG5. The fermentor is subject to changs in pH, temperature, mixing, etc. The regularized pole placement adaptive control algorithm is used for regulation and tracking purposes. The substrate concentration and the dilution rate have been respectively selected as controlled and control variables. The eliminant matrix associated to the pole placement problem is non-singular if the identified input-output model has common poles and zeros. Two solutions have been adopted to deal with this ill-conditioning problem. The first solution consists of monitoring the determinant of the eliminant matrix and the second consists of adding a correction term to the highest degree coefficient of either the numerator or denominator of the process transfer function. A robust recursive identification scheme is used for parameters estimation. The fermentor was interfaced with PC computer using a multitasking operating system. Experiments carried out with the fermentor, illustrate the use of the regularized pole placement adaptive control algorithm.