Iterative learning control based on a hybrid tracking and contour error algorithm

This paper presents a learning algorithm which is based on the iterative learning control (ILC) and tracking/contour error formulation. The contour errors of the free form curve are computed and feedback as the correction signal to generate a new command. It is shown that learning using the tracking error can result in different performance for the free form curve. A modified ILC method is proposed to overcome the problem. It shows that the convergence rate and error performance can be improved by choosing the appropriate weighting during the iteration. Simulations are conducted to validate the proposed ILC scheme. The results show that the modified ILC can perform better than the traditional ILC using the tracking error alone.