Predictor-based output feedback control design for sampled systems with input delay subject to disturbance

• Published in: IET control theory & applications Vol. 11; no. 18; pp. 3329 - 3340
• Main Authors: Hao, Shoulin, Liu, Tao, Zhou, Bin
• Format: Journal Article
• Language: English
• Published: The Institution of Engineering and Technology 15.12.2017
• Subjects: anti‐disturbance predictor feedback; asymptotic stability; control system synthesis; delays; disturbance estimation; ESO‐based predictor feedback; extended state observer; feedback; H∞ control; input delay; observers; predictor‐based output feedback control design; Research Article; robust control; robust H infinity feedback control design; sampled data systems; sampled systems; state prediction; time‐varying disturbance; time‐varying systems; predictor-based output feedback control design; state prediction; time-varying systems; extended state observer; time-varying disturbance; control system synthesis; asymptotic stability; feedback; disturbance estimation; sampled data systems; H∞ control; delays; anti-disturbance predictor feedback; robust control; input delay; sampled systems; robust H infinity feedback control design; ESO-based predictor feedback; observers
• DOI: 10.1049/iet-cta.2017.0504
• ISSN: 1751-8644

In this study, a predictor-based output feedback control design is proposed for sampled systems with input delay subject to disturbance. An extended state observer (ESO) is first constructed to simultaneously estimate the system state and disturbance based on only the output measurement. Then a filtered predictor is constructed by using the estimated state and disturbance to compensate the input delay so as to improve the disturbance rejection performance. For the presence of a constant or asymptotically stable disturbance, a robust H infinity feedback control design based on state prediction and disturbance estimation is proposed to realise no steady-state output error, despite mismatched disturbance. When there exists a time-varying disturbance with deterministic dynamics, such as a sinusoidal type, the proposed predictor can achieve a small prediction error by properly tuning the filter, such that the existing observer-based feedback control methods for delay-free systems can be directly adopted to stabilise such a system with input delay. Moreover, the output error bounds in the presence of time-varying disturbance are quantitatively analysed for using the ESO-based predictor feedback and anti-disturbance predictor feedback, respectively. Two illustrative examples are given to demonstrate the effectiveness and merit of the proposed method.