Digital repetitive controller design via sampled-data delayed signal reconstruction

In this paper, we propose a design method of digital repetitive controllers to track continuous-time periodic references based on sampled-data H∞H∞ delayed signal reconstruction. It is well known that perfect tracking is not possible for arbitrary periodic signals with a fixed period if the plant to be controlled is strictly proper.For this reason, we adopt the internal model control (IMC), with which the repetitive control is cast into the framework of sampled-data H∞H∞ delayed signal reconstruction problem. We also extend this formulation to multi-rate and robust control. Design examples show the effectiveness of our method.