A Priori Integral Persistent Excitation in Conservative Polynomial ODEs with Higher-Order Interactions
Verifying the persistent excitation condition for parameter identification and adaptive control is difficult, and a priori methods that work without knowing system parameters are poorly developed. The goal is to establish integral persistent excitation for conservative polynomial ODEs a priori.
An affine integral excitation condition is defined for measurable bounded trajectories and shown equivalent to trajectories not sticking to affine hyperplanes. Under compact invariance, an absolutely continuous invariant measure, and a nondegeneracy condition, the main theorem establishes that the fraction of time spent near any hyperplane tends to zero. The proof relies on the Birkhoff–Khinchin ergodic theorem and the Novikov–Yakovenko theorem, and is formalized in the Lean proof assistant.
The main theorem yields affine integral persistent excitation for almost every trajectory. The method is applied to a reduced three-wave interaction model in R^6, demonstrating applicability to systems with higher-order interactions.
