轴线测量的中长距离空间直线基准理论及关键技术研究

Domestic warship and ship's propulsion shafting has heavy vibration and serious bearing's uneven wear, the bottleneck of whose improvement is the measurement technology of the curve propulsion shaft line, mainly restricted by the lack of absolute and highly accurate spatial straightness reference in mid-long distance. To solve this problem that straightness reference in mid-long distance has a little large error, here a method for generating a pan-nondiffracting beam with long focal depth is proposed. In addition, a way to produce absolute and highly accurate spatial straightness reference in mid-long distance is studied by combining theoretical analysis, error control, and measurement-compensation. The focus of how to produce spatial straightness reference involve: studying the influence of system parameters' errors and manufacturing errors, obtaining controlling measures for these errors and ensuring the significant feature of the cross-section concentric rings, which ensure significant improvement in the quality of the beam's image in long focal depth; studying the topological characteristics of the cross-section concentric rings, obtaining the statistical regularities of the topological characteristics and ensuring high signal-to-noise ratio, solving the problem of the trueness of image processing, which in turn gives high measurement accuracy of the beam cross-section image's center; detecting and compensating for the beam excursion, producing the spatial straightness reference of pan-nondiffracting beam, whose working distance is longer than 65m, with an actual accuracy of less than 1um/m and a large enough measurement range of offset to the spatial straightness reference. These will provide new theoretical and technological support for the utility of the spatial straightness reference of pan-nondiffracting beam. Therefore, the high accuracy measurement technology of the curve propulsion shaft line can be achieved. This spatial straightness reference can also be applied in the high accuracy measurement of coaxiality of the turbine shafting in aircraft engine and turbonator.

国产舰船轴系的振动大、轴承偏磨严重，主要瓶颈是轴系曲线轴线的测量技术，其关键是缺乏绝对式、高精度、中长距离的空间直线基准。 针对中、长距离直线基准误差较大的难题，本项目提出一种长焦深广义无衍射光束的产生方法，理论分析-误差控制-测量补偿相结合，研究实现绝对式、高精度、中长距离空间直线基准。重点研究空间直线基准实现的关键问题：研究系统参数误差、制造误差的影响，获得误差的控制措施，保证截面同心光环组的特征显著，显著改善长焦深时成像质量的问题；研究同心光环组的拓扑特征，获得其统计规律，保证信噪比高，解决图像处理结果正确度的问题，从而实现了光束截面图像中心测量的高精度；测量、补偿光束的漂移，实现广义无衍射光空间直线基准，工作距离>65m、实际精度<1μm/m和测量范围大，为其实用性提供新理论和技术。 进而将实现轴系曲线轴线高精度测量技术，也可实现航空发动机、汽轮发电机的涡轮轴系等的同轴度精密测量。

本项目围绕中、长距离直线基准误差较大的难题展开研究，目的是提高中长距离无衍射光空间直线基准精度。首先，基于菲涅耳衍射理论，开展长焦深广义无衍射光束成像特性及其影响因素的理论分析与仿真研究，建立长焦深广义无衍射光束的参数化理论模型及其误差模型；其次，为保证无衍射光轴的稳定性和成像质量，根据理论模型优化广义无衍射光的实现系统的光束稳定性和成像质量；然后，基于无衍射光传播时其横截面的光强分布规律——同心光环组特征，研究基于同心光环组的拓扑特征及其统计规律的图像处理算法，提高图像信噪比、同心光环组中心的定位正确度以及图像处理算法的鲁棒性;接着，通过试验获得各种因素引起的光束漂移对广义无衍射光空间直线基准稳定性的影响，利用光束漂移探测器和采取保证图像采集同步性的措施，保证获得光束漂移误差数据的时效性，减小误差数据对振动、温度的敏感性，修正、补偿光束漂移误差；最后，综合上述研究成果，将广义无衍射光空间直线基准应用到船舶推进轴系的轴系校中中，进行轴系轴承孔系的同轴度/轴线偏差、误差评定技术研究，保证轴系轴承孔位姿的安装精度。. 本项目的研究形成了截面同心光环组特征显著的长焦深广义无衍射光束实现技术、基于截面图像同心光环组的拓扑特征的图像处理算法以及长焦深广义无衍射光束漂移的测量补偿技术共3项关键技术；并在项目执行期间，围绕发表了相关学术论文共8篇（其中 SCI 和 EI 共 3篇，中文核心 5篇）及取得的知识产权成果共 3项（发明专利 2项，国防专利 1 项），科技报告1份（获得二级中国国防船舶科技报告）。. 本项目提出的长焦深广义无衍射光束的产生方法和绝对式、高精度、中长距离空间直线基准的实现技术，对提高中长距离无衍射光空间直线基准精度具有理论指导意义，将丰富和发展广义无衍射光空间直线基准的理论和技术，也将为轴系曲线轴线高精度测量技术和突破船舶的轴系校中瓶颈奠定了理论基础和技术储备。