Semi-global adaptive backstepping control for parametric strict-feedback systems with non-triangular structural uncertainties?

In this paper, two semi-global adaptive control schemes are proposed for a class of parametric strict-feedback systems with non-triangular structural uncertainties. Unknown nonlinear functions containing non-triangular structural uncertainties and unknown parameters are allowed to exist in every state equation. Because the linear relation between the state vector and its transformed vector cannot be ensured, the improved backstepping method used to deal with non-triangular structural uncertainties cannot be used directly in controller design. To solve this problem, semi-global stability analysis is introduced in the controller design. As a result, the linear relation mentioned above is no longer needed and thus the stability of the closed-loop system is guaranteed. The effectiveness of the proposed schemes is verified by simulation studies. (c) 2021 ISA. Published by Elsevier Ltd.

Automated summary

This paper proposes two semi-global adaptive control schemes for a class of parametric strict-feedback systems with non-triangular structural uncertainties. By introducing semi-global stability analysis, the problem of using the improved backstepping method directly is solved, and the stability of the closed-loop system is guaranteed.