## Robust passivity and feedback design for minimum-phase nonlinear systems with structural uncertainty.(English)Zbl 0936.93046

The paper deals with affine nonlinear systems of the form \begin{aligned} \dot x & = f(x)+ g(x)u,\\ y & = h(x)\end{aligned} with $$0$$ as “ground state” ($$f(0)= 0$$, $$h(0)= 0$$) and $$f$$, $$g$$, $$h$$ smooth mappings. Passivity and robust passivity are revisited. Further, feedback equivalence to a robust strictly passive system is described. After introducing robust minimum phase systems it is shown that these systems are globally asymptotically stabilizable. The results obtained for systems of relative degree one are then extended for higher relative degrees.

### MSC:

 93D21 Adaptive or robust stabilization 93D10 Popov-type stability of feedback systems 93D09 Robust stability
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