Comments on 'Less conservative conditions for robust LQR-state-derivative controller design: an LMI approach' and new sufficient LMI conditions for invertibility of a convex combination of matrices

Summary: This study proposes less conservative conditions for robust linear quadratic regulator controllers using state-derivative feedback, which can reduce sensor vibrations and uses methods to formulate these conditions. Additionally, necessary conditions for a convex combination of matrices to be nonsingular are provided, and feasibility analysis demonstrates that the proposed conditions can reduce conservatism.