Dynamic frequency scanning interferometry measurement based on optical frequency synchronous motion measurement and error compensation

We present a dynamic frequency scanning interferometry (DFSI) method. Based on conventional frequency scanning interferometry (FSI), superheterodyne interference is introduced to synchronously measure a moving target online. The phase error in the measurement is separated and compensated to eliminate the influence of the Doppler effect caused by the movement of the target. The theoretical model of the measurement method is given, and the influence and characteristics of the moving target on the FSI are analysed. On this basis, a measurement experiment is carried out. The absolute distance measurement standard deviation is 3.47μm in the range of 0.9 m, and the maximum deviation is 6μm. The measurement accuracy of the motion trajectory of 0.1 mm/s ∼1 mm/s uniform motion and 5μm∼25μm/5 Hz ∼50 Hz simple harmonic vibration is better than 0.2μm, and the influence on the absolute distance measurement accuracy of the initial position is less than 1μm. This method can not only cover the shortage of periodicity in the FSI but also address the fact that the measurement accuracy of the existing FSI is reduced due to the Doppler effect and realizes high-accuracy DFSI absolute distance measurements, which has wide application prospects.