Error-Corrective Feedback Compensation to the Feedforward Tracking Control

An error-corrective feedback compensation scheme, in attempt to compensate for the non-idealities of the feedforward control, is derived using the contractive mapping principle. This scheme of compensation is intimately related to several famous controls, including repetitive control, internal model control and sigma-delta modulation, proving a unifying interpretation of the common philosophy of prediction and control behind these control methods. More explanations and references on this viewpoint will be included in the full paper.