Design of optimal disturbance cancellation controllers for a class of disturbances via loop transfer recovery

The authors have proposed the modified loop transfer recovery (LTR) design of the disturbance cancellation controllers for step disturbances. Although the extension to a more general class of disturbances has been considered, the use of the optimal target has not been fully discussed. This paper reformulates the extension and proposes the systematic procedure for designing the disturbance cancellation controller with sufficient stability margins.