A nonlinear sliding surface to improve performance of a discrete-time input-delay system

Bijnan Bandyopadhyay, Fulwani Deepak, Ian Postlethwaite, Matthew Turner

    Research output: Contribution to journalArticlepeer-review

    7 Citations (Scopus)

    Abstract

    A sliding mode controller is proposed for an uncertain input-delay system to enhance performance. A nonlinear sliding surface is proposed to achieve better transient response for general uncertain discrete SISO linear systems with input delay. Both matched and unmatched perturbations are considered and ultimate boundedness of motion is proved. The step tracking problem is analysed. The proposed surface increases the damping ratio of the transformed system (delay free) as the output moves nearer to the setpoint. To simplify the surface design, a linear matrix inequality based tuning procedure is proposed. The control law is designed based on an equivalent control approach which guarantees one step reaching. The scheme is able to achieve low overshoot and low settling time simultaneously which is not possible with a linear sliding surface. Simulation results verify the effectiveness of the proposed nonlinear surface over different linear surfaces.
    Original languageEnglish
    Pages (from-to)1895-1906
    JournalInternational Journal of Control
    Volume83
    Issue number9
    DOIs
    Publication statusPublished - 2010

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