EFFECTS OF NON-PERIODIC DISTURBANCES ON REPETITIVE CONTROL SYSTEMS

摘要

This paper examines non-periodic tracking and disturbance rejection characteristics of repetitive controller designs. Since repetitive controllers learn to cancel disturbances over time, one-time (non-periodic) disturbances have the undesirable effect of reducing tracking accuracy not only in the initial cycle but also in subsequent cycles while the controller "unlearns" the disturbance. This paper discusses the use of disturbance observer feedback to minimize response to non-periodic disturbances during the initial cycle, and adds a new adaptive error saturation element that uses simple statistical techniques to allow the repetitive controller to distinguish between periodic and non-periodic disturbances.