Design of controllers for integrating and unstable time delay systems using polynomial method

The paper presents a methodology of the controller design for integrated and unstable time delay systems. The proposed method based on a polynomial approach and LQ control technique yields a class of CT controllers ensuring setpoint tracking as well as load disturbance attenuation. The 2-DOF control configuration is considered. The resulting controllers obtained via polynomial Diophantine equations and the spectral factorization technique are stable ones. Time delay terms are approximated by a first order Pade approximation, and they are incorporated into the control design as a perturbation. Simulation results are presented to illustrate the proposed method.