Feedforward controller synthesis for uncertain time delay systems via dynamic iqcs

The thesis studies the design problem of a delay-dependent robust H? optimal feedforward plus feedback controller for systems having state and control delays and neutral systems with delays affecting the derivative of states. The controlled system having parametric uncertainties is subject to L2 disturbances. The proposed controller involves two main control loops which are state-feedback and dynamic feedforward controller. The state feedback controller is used as a stabilizing controller whereas the feedforward controller performs the minimization of disturbance effects. Dynamic Integral Quadratic Constraints (IQCs) which consist of frequency dependent multipliers, have been introduced to represent the delays and parametric uncertainties in the system. The degree of the multipliers used in IQCs is increased in order to decrease the conservatism in the obtained results. Sufficient delay dependent criterion in terms of Linear Matrix Inequalities (LMIs) such that uncertain time-delay system is guaranteed to be globally, asymptotically stable with a minimum disturbance attenuation level, is presented in this study. Many numerical examples provided at the end, illustrating the usefulness of the proposed design.