The velociprobe: Pushing the limits with fast and robust control

This article shows the benefit of feedback control algorithm, specifically the H∞ control architecture that we are showcasing, through the improvement of X-ray imaging capabilities in terms of speed of X-ray imaging resulting from large scanning bandwidth, better resolution of the optics scanning stages, better resolution of the Xray diffraction images and reduced imaging artifacts. The open loop drift present in the zoneplate stages and the sample stages are being reduced by H∞ controller for both operation modes; the zone-plate only and the relative displacement case. Better positioning resolution was achieved for the step scanning in closed-loop for both operation modes. At present, the designed controllers are not being utilized to the full potential because of the step scanning technique. The fly-scan technique implemented with the H∞ controllers would reduce the time to scan a target region even more, giving the capability to scan large regions on a sample.