Research On New Laser Scanning Projection System Based On Laser Ranging

Mechanical manufacturing assembly is developing in the direction of digitalization and intelligence.The laser scanning projection system can project the outline of the parts to be assembled in the position to be installed at 1:1 ratio.To prevent installation errors when installing a large number of parts,repeated installation is required,which will improve work efficiency and assembly accuracy.The new laser scanning projection system based on laser ranging in this paper quickly realizes the high-precision calibration of the system using three cooperative targets,and solves the problem that the original laser scanning projection system requires at least four cooperative targets,which requires multiple times to solve because of non-convergence.The main works completed in this paper are as follows:(1)The laser scanning projection technology and laser ranging technology are researched,moreover,a new laser scanning projection system based on laser ranging is designed and constructed with the abovementioned technologies.The projection model of the laser scanning projection system is established.The calibration models of the original laser scanning projection system and the laser scanning projection system based on laser ranging are established.Two calibration models are simulated and analyzed using the particle swarm optimization algorithm.The results show that the calibration accuracy of the original system is 10-6mm and the calibration accuracy of the new system is 10-7mm without considering the errors of the laser beam horizontal deflection angle(H),laser beam vertical deflection angle(V)and measurement distance(D).(2)A simulation analysis of the ranging error of the new laser scanning projection system is performed by using particle swarm optimization algorithm.The results show that,without considering the errors of H and V,the calibration accuracy is about: 1.88 mm,0.265 mm,0.0265 mm,when ranging errors are ± 1mm,± 0.1mm,± 0.01 mm.The simulation results show that the ranging error has a great impact on the calibration accuracy,and the calibration accuracy is higher than the projection accuracy requirement of 0.5mm.(3)In order to reduce the influence on calibration accuracy which is caused by the error of laser ranging,a particle swarm derivative algorithm to eliminate the influence of ranging error on calibration accuracy is proposed.By using particle swarm derivative algorithm to simulate and analyze the calibration model with ranging error,which show that all the calibration accuracy reached 10-7mm without considering the errors of H and V,when the ranging errors are: ± 1mm,± 0.1mm,± 0.01 mm.(4)The principle of circle center extraction of cooperative targets is studied,and seven kinds of circle center extraction including minimum area method,minimum circumscribed circle method,maximum inscribed circle method,simplex search method,least square method,fitted diameter method,and midpoint method are established.Cooperative target circle center solving experiments,calibration experiments,projection experiments are designed at a distance of about 3.5m.The results show that the midpoint method has the highest circle center solution accuracy,the calibration accuracy of the new laser scanning projection system can be faster than 10-5 seconds,and the projection accuracy of the new laser scanning projection system is less than 0.5mm.