High‐Order Predictive Extended State Observer Based Anti‐Disturbance Control for Input‐Delayed Systems Subject to Multi‐Source Disturbances

This article proposes a high‐order predictive extended state observer (HOPESO)‐based antidisturbance control scheme for input‐delayed systems subject to multisource disturbances. By taking an appropriate change of variables, multisource mismatched disturbances in the original system are first converted into the summation of multisource matched ones for a transformed system. Then, an HOPESO is constructed to simultaneously estimate the future system state and the total disturbances. To address a relatively larger input delay, a chain of sequential HOPESOs is designed such that each sequential HOPESO only estimates the future system state and total disturbances over a fraction of the input delay. To further reduce the number of sequential HOPESOs and thus the complexity of the control scheme, another enhanced design of sequential HOPESOs is developed by incorporating all available estimation errors of the related HOPESOs. Correspondingly, predictor‐based antidisturbance controllers are designed to eliminate the adverse impact of multisource disturbances. Meanwhile, the exponential stability analysis for each of the proposed HOPESO‐based antidisturbance control schemes is analyzed with proof. Finally, an illustrative example from the literature is given to demonstrate the effectiveness of the proposed design.