Modified disturbance observer-based control for stable multivariate processes with multiple time delays

In this study, the authors propose a modified disturbance observer-based (DOB) control strategy for input load disturbance rejection, in cases of stable multivariate processes with multiple time delays. Unlike the existing multivariate disturbance observer-based (MDOB) control strategies using approximate inverse model to estimate external disturbances, the proposed MDOB control strategy instead designs a V canonical structure, which can estimate the external disturbances rapidly and exactly. Based on the V canonical structure, the controllers for disturbance rejection are designed analytically by minimizing 2-norm of the outputs caused by disturbances. The tunable parameters of the controllers are determined by considering both the control performance and robustness. Simulation studies demonstrate the effectiveness of the proposed method. (C) 2018 Elsevier Ltd. All rights reserved.