An enhanced $$H_\infty$$ filtering delay dependent criteria for continuous systems with varying time-delays

This paper examines the challenge of designing \(H_\infty\) filters for continuous systems with varying time delays. The filter design incorporates potential variations in gain due to implementation inaccuracies. The new delay-dependent \(H_\infty\) performance is derived by using a novel Lyapunov–Krasovskii functional (LKF) and by employing novel free weighting matrices. The paper establishes existence of \(H_\infty\) filters in terms of linear matrix inequality (LMI). To demonstrate the proposed method’s effectiveness, apply it to a vertical take-off and landing (VTOL) helicopter system in the numerical section.