On the Design of a Novel Actuation Principle for a Piezo Rotary Stage

Synchrotron beamlines and industrial computed tomography (CT) do not only rely on high-brilliance X-rays, but also on high-precision and compact motion systems. More specifically, the scan resolution of three-dimensional X-ray nano-imaging techniques is largely dependent on the rotational accuracy of the sample under test. This is determined by the accuracy of the bearings in the rotary stage and is typically in the order of a few micrometres. This work reports on the design and testing of a novel actuation principle for compact piezo rotary stages in order to increase the scan resolution in above-mentioned applications. The presented actuation principle is based on the concept of a combined actuator and bearing mechanism. In this way, one can actively compensate the error motion of the rotary stage to the nanometre level. Measurements show a radial error motion of 360 nm peak to peak without active compensation and 110 nm peak to peak with active compensation. The axial and tilt error motion, on the other hand, are 130 nm ptp and 37 murad ptp, respectively.