Direct visual servo control achieving nanometer resolution in X-Y-Z

摘要: A novel measurement technique, laterally-sampled white light interferometry (L-SWLI) was developed by the authors of this paper and introduced in (Ibid., "An Ultra Precision Six-Axis Visual Servo Control System", IEEE Transactions on Robotics, unpublished) demonstrating sub-10 nanometer resolution all three x-y-z motion axes a visually guided control system using interferometer-equipped optical microscope. This presents two major improvements L-SWLI as real-time sensor. First, out-of-plane range is increased from several micrometers to 100 um or above employing an objective-z-positioner (OZP). Augmented schemes are for OZP integration. Second, interferogram pattern matching method processing interferograms, leading improvement one order magnitude, under 0.4 nm (RMS). Experimental results presented. Additionally, specially designed experiment confirms that with low-pass-filtered measurement, can measure slowly varying thermal drift accuracy 1-nanometer x-y-z.