Comparative study on first and second order ILC-frequency domain analysis and experiments

Abstract

Aspects of the behavior of a general second order iterative learning control (ILC) algorithm are presented from a frequency domain perspective. This includes stability as well as performance and robustness issues. The basis for the analysis is linear iterative systems and these are briefly described. A design algorithm for second order ILC schemes is proposed and analyzed both theoretically as well as in an experiment. In the experiment, done on a commercial industrial robot control system, the second order ILC design is compared with a first order ILC design. The results from both the analysis and the experiment show that the second order design is not better with respect to performance or robustness.