基于对称离焦双探测器的自聚焦激光扫描投影方法研究

Laser 3D scanning projection is widely used in the precision manufacture andassembly fields for aircrafts, ships and automobiles. However, the use of 2Dscanning mirrors for laser beam deflection and repeating scanning projection leadsto severe flickering when projected complex graphics. On the other hand, owing tothe method of detecting reflected light intensity with a single detector, theaccuracies of calibration by lateral scanning with cooperative targets and axialfocusing are hard to be improved. These problems have become the hot researchtopic in the field of laser scanning projection. Accordingly, the researchcontents are as follows. (1) To achieve accurate axial focusing and calibration bylateral scanning with cooperative targets, a novel automatic focusing laserscanning projection method based on dual detectors in symmetrical defocusingdistance state is studied. (2) To solve the problem of flickering, the algorithmsof feature points extraction from scanning path, control points dilution andscanning projection order optimization are researched. Furthermore, method forscanning path analysis and optimization based on CAD model in IGES file type isproposed. (3) The errors of shape, dimension and position in the developed laserscanning projection are figured out, and methods for the errors assessment andcompensation are studied. The following are innovations of this study. Firstly,The detected module composed by dual detectors which are in symmetrical defocusingdistance state integrates differential intensity detection mode with additiveintensity detection mode, this feature make the accuracy improvement of coordinatetransformation is compatible with the width reduction of scanning laser beam. Thesecond is the method for scanning path analysis and optimization to achieve high-speed and accurate laser scanning projection.

激光3D扫描投影技术广泛应用于飞行器、船舶和汽车等大尺寸部件的精准制造和装配领域。然而，由于该技术采用双轴扫描振镜实现激光束的偏转和循环扫描投影，导致在投影复杂图形时存在较严重的频闪现象。同时，由于采用单个探测器进行反馈光强探测，制约轴向汇聚精度和对合作目标的横向扫描标定精度的提高。有鉴于此，本项目研究内容为：（1）为实现精准的轴向自动聚焦和针对合作目标的准确横向扫描定位，研究基于对称离焦双探测器的自聚焦激光扫描投影方法；（2）为解决频闪问题，研究扫描路径特征点提取、控制点稀释和路径点序优化，提出基于IGES等CAD数模的扫描路径解析和优化方法；（3）研究该技术中投影图形形状误差、位置误差的标定和补偿方法。项目创新在于：双探测器对称离焦探测模块将差分式光强探测和加和式光强探测相结合，兼顾实现投影线宽压缩和坐标系转换计算精度的提高；扫描投影路径的解析和优化方法，实现复杂图形高速准确扫描。

激光3D扫描投影技术广泛应用于飞行器、船舶和汽车等大尺寸部件的精准制造和装配领域。本研究主要解决该技术与仪器在投影复杂图形时存在的较严重频闪问题，提高轴向汇聚准确度和合作目标横向扫描标定准确度。本项目的研究内容为：（1）为实现精准的轴向自动聚焦和针对合作目标的准确横向扫描定位，研究基于对称离焦双探测器的自聚焦激光扫描投影方法；（2）为解决频闪问题，研究扫描路径特征点提取、控制点稀释和路径点序优化，提出基于IGES等CAD数模的扫描路径解析和优化方法；（3）研究该技术中投影图形形状误差、位置误差的标定和补偿方法。.本研究提出了具有我国自主知识产权的双探测器对称离焦探测方法，将差分式光强探测和加和式光强探测相结合，兼顾实现投影线宽压缩和坐标系转换计算精度的提高；完成了扫描投影路径的解析和优化方法，实现了复杂图形高速准确扫描，并搭建了具有我国自主知识产权的新型激光扫描投影系统。.项目完成了基于对称离焦双探测器的新型自聚焦激光扫描投影方法的研究，实现了较大纵深尺度复杂曲面上激光扫描投影图形的精准动态自聚焦，提高了投影定位准确度，激光扫描投影图形的形状和位置准确度均优于0.2mm；掌握了基于图论学的扫描路径特征点提取、控制点稀释和路径优化理论与方法，提出了新的基于欧拉路径优化方法的IGES数模解析和扫描优化方法，初步解决了现有扫描投影仪器投影大量复杂图形时存在的“频率闪烁”问题，基于上述研究搭建了新型激光扫描投影系统，能够在5m的投影距离上清晰扫描投影出6m×6m范围的7×7纵横相间方格图形而不发生“频率闪烁”现象。.本项目的研究成果能够为激光扫描投影仪器的自主知识产权国产化提供关键技术支撑，相关技术与仪器国产化后可推广应用于我国航空航天的先进制造与智能装配领域，解决复合材料数字化制造与铺贴定位的卡脖子难题。