Design of optimal disturbance cancellation controllers for sinusoidal output disturbances via loop transfer recovery

This paper discusses an application of the classical loop transfer recovery technique to the design of the optimal disturbance cancellation controller for the sinusoidal output disturbance with known frequency. The optimal output feedback controller is constructed based on the separation principle. The target of the design is chosen as the estimation error dynamics including the internal model for the sinusoidal disturbance. It is shown that the target feedback property can be recovered by using the weighting parameter in the performance index. A numerical example is presented to illustrate the effectiveness of the proposed design.