Linear Feedback Equivalence and Control of an Unstable Biological Reactor

A novel method for the feedback control of an unstable, continuous stirred tank bioreactor is described in this paper. The models considered describe the growth of a single microorganism on a single, rate limiting substrate. A theoretical discussion demonstrates that for models of this type, a global feedback transformation exists which linearizes the state response. Such a transformation is computed using the methods of Hunt, Su and Meyer (1983). A controller is computed using linear state feedback control, and an extended Kalman filter is used to estimate unmeasured state variables. Simulation results demonstrate satisfactory control behavior over a wide region of the phase plane.