Robust Discrete-Time Spatial Repetitive Controller

This brief proposes a novel discrete-time realization of the spatial repetitive controller topology, an internal model principle-based regulator, which deals with the exogenous position-dependent periodic signals. A simple procedure is proposed in order to estimate the time-varying delay required to implement this spatial controller, resulting in a single recursive equation. A robust synthesis methodology based on a convex optimization problem constrained by linear matrix inequalities is also presented in order to guarantee the closed-loop system stability and performance in the presence of uncertain plant dynamics. The proposed design and implementation methods are validated on a direct current motor subject to angle-dependent disturbances.