Research On High Precision Line Scanning Laser Triangulation Measurement Instrument

With the rapid development of technology and the continuous improvement of production efficiency,the traditional manual measurement of product dimensions has gradually been replaced by the automatic measurement.How to measure product dimensions online more quickly and accurately in the production process has become a research hotspot in the field of intelligent manufacturing.Compared with traditional dimensional measurement methods,laser triangulation is a non-contact measuring instrument with the advantages of simple structure,strong applicability,high accuracy and less susceptible to the influence of the measured surface texture,color and ambient stray light.It can be used widely for the rapid and real-time inspection of the object dimensions.Compared with the point scanning type,the line scanning laser triangulation measurement instrument has higher measurement efficiency and is more preferred in the manufacturing.The contents of the thesis are focused on how to improve the accuracy of the line scan laser triangulation instrument.Firstly,the working principle of the line scanning laser triangulation instrument is introduced.The intensity distribution of the line spot emitted from the illumination system of the instrument and the image captured by the detector are simulated with the computer graphics methods.In order to improve the measurement uncertainty of the instrument,the intensity uniformity of the line spot optimized for the illumination system and an imaging system with a double telecentric structure is designed.After that,the prototype of the instrument is installed,calibrated and tested,and the contributing factors of the measurement uncertainty are analyzed.Finally,three optical methods to suppress speckle are analyzed and simulated,namely the time average method,the angle diversity method and the wavelength diversity method,and the suppression performance is verified by the experimental equipment.This paper provides a solution to further improve the measurement uncertainty of line scanning laser triangulation measurement instrument.