24.04.2013 Views

Nonlinear Control Sy.. - Free

Nonlinear Control Sy.. - Free

Nonlinear Control Sy.. - Free

SHOW MORE
SHOW LESS

You also want an ePaper? Increase the reach of your titles

YUMPU automatically turns print PDFs into web optimized ePapers that Google loves.

7.3. INPUT-TO-STATE STABILITY (ISS) THEOREMS 187<br />

Definition 7.1 with<br />

aj1oa2oX (7.7)<br />

k1 = a21(al(r)) (7.8)<br />

k2 = X-1(min{k1iX(r,,)}). (7.9)<br />

Theorem 7.2 (Global ISS Theorem) If the preceeding conditions are satisfied with D = 1R'<br />

and Du = 1Wt, and if al, 02, a3 E )Coo, then the system (7.1) is globally input-to-state stable.<br />

Proof of Theorem 7.1: Notice first that if u = 0, then defining conditions (7.5) and<br />

(7.6) of the ISS Lyapunov function guarantee that the origin is asymptotically stable. Now<br />

consider a nonzero input u, and let<br />

Also define<br />

ru f SupIuTII = IuIIG_,<br />

t>O<br />

c f a2(X(ru))<br />

0

Hooray! Your file is uploaded and ready to be published.

Saved successfully!

Ooh no, something went wrong!