Robust analysis for the lagrange stability of the pendulum-like system

This paper is concerned with the problem of robust lagrange stability of pendulum like systems with norm constraint structured uncertainties. For the robust lagrange stability analysis of uncertain pendulum like systems, by applying the structured singular value of a transfer function to structured uncertainty, a new frequency domain condition is obtained. Furthermore, based on the analysis results, and using KYP lemma, a dynamic output feedback controller for the closed loop systems guaranteeing lagrange stability is designed.