ABSTRACT
Two-stage anaerobic digestion (TSAD) has emerged as a promising technology for both organic pollutant purification and biogas production. In industrial applications, however, TSAD process measurements are subject to multi-rate sampling, different time delays, and sensor noise, while certain critical process states (e.g., concentrations of anaerobic microorganisms) remain unmeasurable in real time. To address these challenges, this study proposes a multi-rate sampled and delayed output signal prediction-based (MSDOSP) observer for TSAD processes, which simultaneously reduces measurement errors and estimates key unmeasurable states. The proposed MSDOSP observer utilizes multi-rate sampled measurements with time delays and noise to simultaneously reconstruct accurate continuous signals and provide real-time state estimation. The vector small-gain theorem is employed to rigorously establish the stability conditions of the observer. Finally, the performance of the MSDOSP observer was verified on the MATLAB/Simulink platform compared with two existing methods.
International Journal of Robust and Nonlinear Control, EarlyView. Read More
