A NEW METHOD FOR THE ADAPTIVE DETERMINATION OF OPTIMUM PH AND TEMPERATURE

An adaptive control algorithm for on-line determination of the optimal temperature or pH for biomass production in a continuous fermenter is presented. The algorithm requires no prior information and uses a dynamic Hammerstein model to identify parameters and to estimate an optimal steady-state control value. A check of the estimated performance measure second derivative is included to ensure that the target extremum is an optimum. The process is driven toward this optimum with a variable step size that depends on the quality of the on-line identified model. Numerical simulations are performed on a dynamic chemostat model that incorporates a metabolic time delay. The algorithm successfully finds the optimum temperature or pH values and maintains the reactor at the optimum steady state.