Broadband damping of high-precision motion stages

Abstract

This paper presents a method to apply robust mass dampers on an industrial high-precision motion stage design and shows a substantial improvement of the modal damping of the stage's resonances. The robust mass damper is a passive add-on device with very high damping. The damper placement is based on mode shape analysis. Algorithms are used to optimize the damper parameters such that the suppression factor of resonances over a specified -control relevant- frequency range is maximized. Damper hardware is designed based on the optimization results and the approach is validated by experimental modal analysis. As a result, the equivalent modal damping of the resonances visible in the frequency response function is increased by at least 16 times between the relevant frequencies (between 1 and 4kHz) and, in addition, by 10 times up to 6kHz. The time response with robust mass dampers shows an amplitude decrease rate which is 20 times faster in comparison with the stage without dampers. The stage's mass increase amounts less than 2% to obtain this result. The ability to create broad-banded damping by RMDs with a limited amount of mass, in case of a realistic and complex motion stage designs is explicitly proven in this paper.