Abstract
This work removes the critical assumptions of continuity, differentiability, and state-independent boundedness, which are typical of compounded disturbances in disturbance observer-based adaptive designs. Crucial in removing such assumptions are a novel observer-based design with state-dependent gain in place of a constant one, and a novel set-invariance design. The designs use different a priori knowledge of the disturbance, but they can both handle state-dependent (e.g., possibly unbounded) disturbances, as well as non-smooth (e.g., non-differentiable and jump discontinuous) disturbances. The tracking error is proven to be as small as desired by appropriately choosing design parameters. For the second design, which uses the least a priori knowledge of the disturbance, stability is proven by enhancing Lyapunov theory with an invariant-set mechanism, so as to construct an appropriate compact set resulting an invariant set for the closed-loop trajectories.
Original language | English |
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Article number | 8606962 |
Pages (from-to) | 598-604 |
Journal | IEEE Transactions on Fuzzy Systems |
Volume | 27 |
Issue number | 3 |
DOIs | |
Publication status | Published - 2019 |
Bibliographical note
Accepted Author ManuscriptKeywords
- Disturbance observer
- fuzzy adaptive control
- invariant set
- non-differentiable disturbance