A Theoretical and Experimental Study of the Vibratory Dynamics of High-Precision Optical Positioning Systems

Abstract

At the Advanced Photon Source (APS), a state-of-the-art synchrotron radiation facility at Argonne National Laboratory (ANL), high-precision optical positioning systems are needed to conduct a wide range of experiments using the high-brilliance X-ray beam. Precision may be compromised by low-level, low- frequency vibrations from flow-structure interactions in the cooling systems and from facility-based distur bances propagating through the floor. To predict the vibratory response of the positioning systems, a linearized multibody formulation has been developed. It has been applied to specific example cases—an optical table and a mirror support system—used at the experimental stations of the APS. Comparisons of resonant fre quency and mode shape predictions based on the theoretical formulation with experimental measurements il lustrate the crucial importance of properly modeling the kinematic joints and components that comprise these multibody structures. Improved experimental and theoretical methods have been introduced to estimate their dynamic properties. The results obtained by theory compare well with experimental findings. The proposed methodology is precise and generic in predicting the coupled multidimensional, multi-degree-of-freedom vi bratory motion of the positioning systems for the given positioning configurations. It is easily adaptable to numerous systems at the APS and similar facilities.