Simultaneous measurement of five-degree-of-freedoms error motion of rotary axis based on multi-principle fusion method

Abstract This paper proposes a method for the simultaneous measurement of five-degree-of-freedoms error motions of a rotary axis based on multi-principle fusion, including the curved edge diffraction principle, auto-collimation principle, and laser triangulation principle. The proposed measurement system comprises laser sources, beam splitters, a right-angle mirror, photodiode detectors (PDs), a plane mirror, four-quadrant PDs, and mechanical structures. Mathematical models are established for these three optical measurement methods. The calibration results indicate that the radial displacement residual range is ±0.38 μm within a measurement range of ±30 μm, the axial displacement residual range is ±0.46 μm within ±20 μm, and the tilt angle residual range is ±0.40 arcsec within ±50 arcsec. Experimental tests conducted on a DD motor show that the radial error motion range is −0.727–0.644 μm, the axial error motion range is −4.053–5.876 μm, and the tilt error motion ranges around X -axis is −2.728–4.851 arcsec and around Y -axis is −4.728–3.872 arcsec, respectively.