A specific repetitive control algorithm for continuous and digital systems: study and application

This paper deals with a repetitive control law specifically designed for systems submitted to a periodic reference input or periodic perturbations. The studied algorithm is intended to improve the system behaviour by using the control signals applied to the plant input during the previous periods. After a stability study briefly recalled for multivariable continuous systems, the connection with sampled systems is developed to emphasize the main differences between these two aspects. The paper ends with an application to magnetic bearings.