Robust stability and [formula omitted] control for networked control systems with transmission delay and its application to 2 DoF laboratory helicopter.

This article explores the stability analysis and control synthesis of networked control systems (NCSs) with uncertainty and transmission delay via a new quadratic polynomial negative-definiteness method. First, a novel negative-definiteness method of quadratic polynomials is proposed by considering two independent parameters. Several existing methods in the literature are encompassed as particular examples. Furthermore, a novel delay-product Lyapunov–Krasovskii functional(LKF) is presented to exploit more delay convexity information. Then, new hierarchical H ∞ stability and stabilization conditions are developed according to the proposed quadratic polynomial negative-definiteness method and the delay-product LKF. Finally, the generality and effectiveness of the established conditions are experimentally shown for a 2-degrees of freedom (DOF) laboratory helicopter system. [ABSTRACT FROM AUTHOR]