An enhanced velocity-based algorithm for safe implementations of gain-scheduled controllers

ABSTRACT

This paper presents an enhanced velocity-based algorithm to implement gain-scheduled controllers for nonlinear and parameter-dependent systems. A new scheme including pre- and post-filtering is proposed with the assumption that the time-derivative of the controller inputs is not available for feedback control. It is shown that the proposed control structure can preserve the input–output properties of the linearised closed-loop system in the neighbourhood of each equilibrium point, avoiding the emergence of the so-called hidden coupling terms. Moreover, it is guaranteed that this implementation will not introduce unobservable or uncontrollable unstable modes, and hence the internal stability will not be affected. A case study dealing with the design of a pitch-axis missile autopilot is carried out and the numerical simulation results confirm the validity of the proposed approach.

KEYWORDS:

• Enhanced velocity-based algorithm
• gain-scheduling
• hidden coupling terms

Acknowledgments

The authors would like to thank the Editor-in-Chief, the Associate Editor, and the anonymous reviewers for their constructive comments, which helped improve the quality of this paper.

Disclosure statement

No potential conflict of interest was reported by the authors.

Notes

1. Note that this condition is necessary but not sufficient to guarantee the closed-loop stability.

Additional information

Funding

This work was supported by NSERC [grant number RGPIN-2014-03942], [grant number RGPIN-312116-13].