Robust repetitive control with an application to a linear actuator

Linear actuator based servo systems are used in many applications of a repetitive nature where they are required to track periodic references in the presence of plant uncertainties and nonlinearities such as nonlinear friction. Achieving the desired tracking accuracies in such uncertain linear actuator systems requires a control method which is capable of achieving perfect cancellation of the periodic uncertainties. One such control technique is the repetitive control method. To cater for the requirements of many LA systems with unknown nonlinearities and uncertainties, this thesis proposes robust repetitive control methods for achieving fast transient response, improved robustness and improved tracking performance.