Nonsmooth adaptive stabilization of cascade systems with nonlinear parameterization via partial-state feedback

We prove that under an appropriate input-to-state stability condition, it is possible to achieve global adaptive stabilization for a class of nonlinearly parameterized cascade systems, using a C⁰ partial-state adaptive regulator. This result complements the earlier work on adaptive control of inherently nonlinear uncertain systems with uncontrollable unstable linearization, which cannot be dealt with by any smooth adaptive control scheme.