Design and Control of a Table-top Vibration Isolation System With Zero-power Gravity Compensation

Abstract

This paper presents the design, implementation and evaluation of a vibration isolation system with a magnetically levitated platform and tunable zero-power gravity compensation. The system, motivated by the stringent requirements of high-precision applications, employs Lorentz actuators for the platform's six degrees of freedom. Zero-power gravity compensation is achieved by electropermanent magnets, allowing adaptation to a varying payload while maintaining a constant operating point. Using decoupling transformations, the platform is stabilized by decentralized position control. For vibration isolation in the vertical direction, the position control bandwidth is reduced to 8 Hz by compensating the negative stiffness of the electropermanent magnets, resulting in an attenuation of floor vibrations with -40 dB/decade above this frequency. Acceleration feedback further reduces the transmissibility by 9.7 dB (67%). The tunable gravity compensation supports a total load of 6.34 kg and reduces the power consumption of the Lorentz actuators by 98.9%.