Profile measurement using a gyro (10th report)

Effect of the phase mismatch for the gyro rotation

Abstract

Profile shape evaluation by detecting tangential angles of the profile is competent for large objects, because it is not affected by shape references, which are difficult to be defined enough accurately for allover the object. We consider adopting a gyro for detecting the angles. Gyros derive angles from the detected angular velocities and are not restricted in their measurement directions or distances, because they do not need any angular references. However, they are suffered from instabilities in their measurements. We rotate a gyro around an axis perpendicular to its sensitive axis, and derive angles of the gyro rotating axis against the earth rotating axis, those are the latitudes and the azimuths, without being affected by the instabilities; however, the derived latitudes seem to be proportional to the gyro rotating rate. Here, we focus on the phase mismatch between the forward and the inverse rotations. The simulation results agree well with the experimental results except for the faster rotating rate of 1 rps.