Investigation Of The Spatial Coordinate Of Laser Tracking Measurement System Based On DSOT-PSD

The spatial coordinate measurement technology plays an important role in the field ofengineering measurement. Measuring the spatial coordinate based on the laser tracking measurementtechnology is a new technology, which acts an important role in the large size-dynamic spatialcoordinate measurement, the assembly of large structures and the other aspects. This papersummarizes the characteristics of the existed spatial coordinate of the laser tracking measurementmethod and system, integrates the advantages of the alone stand laser tracker and the double standtheodolite measuring system, and designs a new spatial coordinate measurement system based on thedouble spots overlapped PSD and the laser tracking technology. This system not only realizesautomatic tracking measurement liking laser tracker, but also uses the space triangulation method,avoiding using laser interferometer, to realize absolute position measurement. Furthermore, the opticalpath blocked by the moment does not affect the measurement results.The principle of the measurement system is analyzed in the paper, and the system overall schemeis designed, including the system hardware platform, the PSD measurement probe, the software ofdata acquisition and motion control. The PSD sensor is considered as the target on the measurementprobe, receiving the laser spot signals, and forming the measuring triangle. A successiveapproximation algorithm is used to make the double spots alternately tracking on the PSD, and theautomatic tracking process is realized in the measurement platform. The principle of PSD collectingspot center of gravity is used to and judge the double spots overlap and to measure the information ofspatial coordinate.An8th level turbine rotor blade of a certain type aircraft engine is taken as measuring object. Thethree coordinate measurement machine and our measurement system is used to measure the surfaceprofile respectively. The results indicate that the precision of our measurement system is atsub-millimeter level, and the error is varied in the range of+0.3mm~-0.41mm when the distancebetween the platform and the probe is about2m. It basically meets the requirements of large sizecoordinate measuring. The error analysis and compensation is applied for a series of errors that mayoccur, and a mathematical model with error compensation is established in the coordinatemeasurement system.