Design of a plug-in type repetitive controller for periodic inputs

This paper presents some practical design criteria for a plug-in type repetitive controller to achieve good tracking performance within a specified frequency range. Upper and lower bounds of the repetitive controller parameters that ensure the stability and the desired performance are derived. It has been found that the decay rate of the tracking error due to periodic inputs is related to the peak value of a defined regeneration spectrum function. The control performance of the present method is evaluated in an experimental software cam system, which needs periodic linear motions, where the real-time control algorithms are implemented using a floating-point digital signal processor (DSP). Both computer simulation and experimental results are presented to illustrate the effectiveness of the proposed repetitive controller design.