Research On Laser Scanning Path Planning And Error Compensation For Free-form Surface Based On Multiple Constraints

With the increasingly high requirements of workpiece surface detection,not only in time,but also in accuracy,laser measurement is also more and more widely used in industrial applications.However,the accuracy of laser measurement and point cloud quantity processing have always been a concern of people.In this paper,a laser scanning path optimization study based on error constraint and a parallel scanning strategy based on curvature constraint are proposed.The two scanning strategies respectively achieve the goal of reducing the error of point cloud data and optimizing the point cloud distribution.These two scanning path methods are integrated into the laser scanning path planning to reduce the laser point cloud error and optimize the point cloud distribution in the point cloud,which verifies the effectiveness and practicability of the proposed method.This paper studies two problems,namely,large error and unreasonable distribution of point cloud.The main contents and innovative achievements are as follows:(1)In-depth analysis of the existing principle of laser scanning path planning and research status quo,learning and introduces the principle of laser measurement has the corresponding measurement system,and point cloud data transformation,and through the scanning depth and scan Angle two constraints implements a equidistant parallel scanning strategy,based on error for subsequent research of laser scanning path optimization constraints and partition based on the curvature constraint contour parallel scanning strategy provides a solid theoretical basis.(2)Based on the isometric parallel scanning strategy and curvature constraint conditions,a parallel scanning strategy for partitioned contour was proposed to solve the problem of unreasonable point cloud distribution obtained by laser scanner when measuring the surface contour of workpiece.The curvature of point cloud was calculated,the threshold value of curvature was set,and the point cloud was segmented.Conventional parallel scanning strategy was used for regions with less curvature,and parallel scanning strategy was used for regions with greater curvature.Combined with two scanning strategies,this method optimizes the number of point clouds in different curvature regions to different degrees before laser scanning.Through experiments,it is found that unreasonable point cloud distribution can be effectively optimized.(3)Based on the isometric parallel scanning strategy,an error constraint condition was added to propose a scanning path planning strategy suitable for long-distance laser scanning.For the curved surface with great curvature change,the scanning error caused by scanning depth and scanning Angle is used to establish the relationship among the three in the scanning process.By minimizing the error as a constraint condition,a single optimal scanning pose was found and the scanning path with the minimum error in each area was constructed.Will get the laser scanner before optimization and after optimization of point cloud data is compared with the measured data of three coordinate measuring machine,laser scanners as experimental object,the calibration points in different location in the former data,also select the same position in the latter point,on the basis of the latter,the contrast error of the two,can effectively reduce the scanning error found by experimental contrast.To sum up,this paper studies the two main aspects in the laser measurement process,proposes the corresponding laser scanning strategy,reduces the measurement error caused in the laser measurement process,and optimizes the unreasonable distribution of the point cloud.