Residual vibration suppression using Hankel iterative learning control

In this paper, we present a new approach for reduction of residual vibrations in point-to-point motions, based on iterative learning control (ILC). The approach is to add a signal to the command input during the point-to-point motion, chosen such as to compensate for the residual vibration. A special form of ILC with separate actuation and observation time windows is shown to find the required input. Optimal suppression is obtained by iteratively updating the command signal, using the measured residual vibrations and a newly designed control strategy. This strategy incorporates 1) robustness to model uncertainties and unmodeled dynamics and 2) the capability of shaping the command signal to limit the command amplitude. In an application on a flexible system, we show that the presented approach is successful in suppression of residual vibrations with a minimized maximum command amplitude