6-DoF Active Vibration Isolation without Tilt-Horizontal Coupling

摘要

High precision measurement instruments, like electron microscopes, aim for imaging resolutions of 100 picometer (pm) RMS. The maximum relative position between sample and the measurement components should be in the order of 25 pm RMS. To reach this high accuracy the instrument is placed on a vibration isolated platform. The positioning stages in these high end measurement systems typically have a bandwidth in the order of 150 Hz. The maximum allowed vibration levels are estimated to be: x_(max) = error · (2πf_(BW))~2 ≈ 40μm/s~2 RMS. An active vibration isolation system can be used to reach this performance. The active vibration isolation requires a high bandwidth to reject external noise sources and low noise sensors to limit self excitation. Mi-Partners has developed an active vibration isolation system (AVI) with a high bandwidth and low noise components.