Chinese Journal of Chemical Engineering, Vol.23, No.11, 1801-1810, 2015
Nonlinear state estimation for fermentation process using cubature Kalman filter to incorporate delayed measurements
State estimation of biological process variables directly influences the performance of on-line monitoring and optimal control for fermentation process. A novel nonlinear state estimation method for fermentation process is proposed using cubature Kalman filter (CKF) to incorporate delayed measurements. The square-root version of CKF (SCKF) algorithm is given and the system with delayed measurements is described. On this basis, the sample-state augmentation method for the SCKF algorithm is provided and the implementation of the proposed algorithm is constructed. Then a nonlinear state space model for fermentation process is established and the SCKF algorithm incorporating delayed measurements based on fermentation process model is presented to implement the nonlinear state estimation. Finally, the proposed nonlinear state estimation methodology is applied to the state estimation for penicillin and industrial yeast fermentation processes. The simulation results show that the on-line state estimation for fermentation process can be achieved by the proposed method with higher estimation accuracy and better stability. (C) 2015 The Chemical Industry and Engineering Society of China, and Chemical Industry Press. All rights reserved.