Robust inverse control strategy for dissolved oxygen concentration based on disturbance boundary estimation

Abstract

Wastewater treatment processes (WWTPs) possess the characteristics of multiple disturbances, which make it difficult to achieve the accurate control of desired dissolved oxygen (DO) concentration. To address this issue, this paper proposes a robust inverse control strategy based on disturbance boundary estimation (DBE‐RIC). First, a nonlinear disturbance observer based on disturbance boundary estimation is introduced to reconstruct the disturbances, which enables DBE‐RIC to deal with internal and external disturbances simultaneously. Second, an inverse controller based on inverse transformation and the reconstructed disturbance signals is designed to obtain the control law under unknown dynamics of WWTPs. Third, a projection operator is presented to adjust the controller parameters online. Then, the RIC controller can accomplish the accurate tracking control of DO concentration. Furthermore, the stability of the proposed strategy in the sense of Lyapunov and the guidelines associated with the control parameters are given. Lastly, the experimental results on the benchmark simulation platform BSM1 demonstrate the feasibility and superiority of DBE‐RIC compared to other methods.