Abstract
A method of constructing a state observer for a continuous fermentation process is presented in this paper. The process is expressed by a growth model describing the growth rate of the microorganisms and the consumption rate of limiting substrates and by a product model for product synthesis. These models are described by ordinary differential equations to represent a completely stirred tank fermentation system. The growth models we consider here are general models which include the Monod model as a special case.
Firstly, conditions for constructing the state observer for the growth are obtained based on the fact that the state observer derived from growth models have nonnegative solutions as in growth models.
Secondly, conditions for designing the state observer for the estimation of the growth rate of and product rate from the microorganisms are obtained using the results of the present authors on a stability problem for the error equation of state estimation in which the time varying system matrix reduces to a triangular matrix by appropriately choosing the design parameters.
A numerical example is included to show the performance of the observer proposed.
