Using Optimal Filters for Plug-in Type Repetitive Controllers for Periodic Inputs

This paper proposes some solutions to optimize the Butterworth filter from the structure of plug-in type repetitive controllers, as well as the use of the Bessel filter, which offers a simpler way of choosing the anticipatory factor from the repetitive controller structure. The comparative analysis of the two types of filters was made on the basis of three criteria: 1) the standard deviation of the error in the control loop, where the first type of filter proved to be superior; 2) ease of obtaining the optimal value of the anticipative parameter, in which case the Bessel filter is preferred; 3) sensitivity to changes in the filter parameters and/or process model, where the second filter is also preferred