Adaptive reductions of the vibrations from a vacuum pump for high-precision equipment

This paper describes experiments with active vibration reduction on a setup with a vacuum pump that is tightly coupled with high-precision equipment. The precision of this equipment is critically dependent on the level of the vibrations that are introduced by the vacuum pump. The vibrations were reduced with a novel adaptive control scheme in a multi-input multi-ouput feedback configura-tion. Due to the efficiency of the algorithm, relatively high sampling rates of 12 kHz were possible. The convergence properties of this algorithm allowed effective tracking of the varying excitation spectrum. Combined with the use of programmable digital minimum-phase reconstruction and anti-aliasing filters on dedicated hardware, effective broadband control was obtained in the frequency range of 100 Hz to 5 kHz, leading to an average broadband reduction on the error sensors of 11.3 dB.