Research On Automatic Measurement Technology Of Components Based On Laser Scanning Technology

Traditional detection methods based on analog delivery are unable to meet the requirements of digital manufacturing in aircraft industry.In recent years,domestic aircraft manufacturers have introduced a variety of digital measurement equipment.Digital measurement equipment is widely used in shape detection of aircraft structural and spatial pose measurement.The scanning system in which digital measuring equipment is installed at the end of the robot,to achieve automated scanning measurements of aircraft components is an inevitable trend in aircraft digital measurement.Scanning trajectory planning is a key step in automated scanning progress.Reasonable scanning trajectory planning can effectively improve scanning quality and efficiency.In this paper,a laser scanner is mounted at the end of the industrial robot to compose a robot scanning system and fullfill the shape detectionof large components of the aircraft,and a trajectory planning and optimization method aiming at improving the measurement accuracy is proposed.The main research contents of this paper are as follows:(1)Developed an proposal for automated shape measurement of aircraft component.Firstly,the characteristics of aircraft components and their shape measurement requirements are analyzed.The measuring equipment and carrier are selected according to the measurement requirements,and the robot scanning system is therefore constructed.Then the components of the scanning system are introduced,including industrial robot system,laser tracker system and laser.Scanner,clamping and triggering mechanism and scanning control software;finally,the coordinate unification method and system workflow in the measurement process.(2)Established a system error prediction model of the laser scanner.After analyzing the measurement error of the laser scanner,it is found that the systematic error in the laser scanner measurement data is affected by the scanning parameters.Therefore,the variation of the system error of the laser scanner is studied experimentally.The experimental results show that the system error of the laser scanner is bilinear with the in-plane angle and the out-of-plane angle.Based on the experimental results,the system error prediction model is established.(3)A trajectory planning and optimization method is proposed.Firstly,the initial trajectory is generated in CATIA.In order to improve the efficiency of trajectory generation,the trajectory is automatically generated through the secondary development program in CATIA.Then the particle swarm algorithm and the systematic error prediction model are used to optimize the surface scanning trajectory.The scanning trajectory that satisfies the scanning constraint and the lowest systematic error is obtained.Finally,an improved Hopfield neural network optimization method is proposed for the overall feature scanning order problem,and the feature scanning sequence with the shortest generation time is generated.