Delay-dependent feedforward control of uncertain neutral time-delay systems via dynamic IQCs

This paper deals with the design problem of a delay-dependent H8 based robust optimal feedforward controller for a class of time-delay control systems having state delays, control delays and neutral delays when the system is subject to norm bounded uncertainties. The proposed scheme in this study is formed by two independent loops which include state-feedback and dynamic feedforward controller. The delay and parametric uncertainty effects are represented by dynamic Integral Quadratic Constraints (IQCs). Furthermore, sufficient delay-dependent criteria is developed in terms of Linear Matrix Inequalities (LMIs) such that the time-delay system with parametric uncertainty is guaranteed to be asymptotically stable with a minimum disturbance attenuation level. The achieved results on the minimum allowable disturbance attenuation level in the provided numerical examples are exhibited to be less conservative in comparison to those of controllers having only feedback loop.