自稳定相移式数字散斑干涉技术内窥测量方法研究

Precise measurement of 3D deformations of key structures is of significant importance in the high-tech fields, such as advanced manufacturing engineering and aerospace. Newly-developed Endoscopic Digital Speckle Pattern Interferometry extends the application range of the traditional Digital Speckle Pattern Interferometry by its capability of measuring the 3D deformations on the inner surfaces of cavities or holes which have narrow entrances. However, it is still a technique that cannot be used in the practical engineering due to the low-quality phase maps it obtained and the sensitivity to the environmental disturbances. This project proposes a self-stabilized phase-shifting Endoscopic Digital Speckle Pattern Interferometry, with which the measuring accuracy and the anti-interference ability of the measuring system are both improved. In the project, the theory of the endoscopic measurement using the self-stabilized and phase-shifting Endoscopic Digital Speckle Pattern Interferometry is studied, the theories and methods of the all-fiber setup and its self-stabilization are also studied, the methods of the phase shift and its in-situ calibration are investigated, and a self-stabilized experimental system is built to achieve the measurements of the 3D deformations in micro/nano- meter scale. A Fiber Michelson Interferometric system is embedded into the Endoscopic Digital Speckle Pattern Interferometric setup by using Wavelength Division Multiplexing technology and the property of fiber Bragg grating. Its outputs are utilized to stabilize the fiber optical path as feedback signals, as well as to in-situ calibrate the phase shift. The research aids in the establishment of the theoretical foundation for the engineering applications of the Endoscopic Digital Speckle Pattern Interferometry, and the improvement of the test ability of key structures in the high-tech fields.

关键结构件三维变形的精密测量在先进制造业和航空航天工业等尖端领域具有重要意义。最近发展的内窥式数字散斑干涉技术可以测量入口狭小的空腔或孔洞内表面的三维变形，弥补了传统数字散斑干涉技术只能测量物体外表面的不足；然而现有的技术所得到的相位图质量差，测量结果不理想，系统抗干扰能力弱，因此还难以在实际工程中得到应用。本项目探索自稳定相移式数字散斑干涉技术的内窥测量理论，探讨其全光纤光路以及光纤自稳定的理论与技术，研究相移技术及其原位标定技术的实现方法，建立抗干扰能力强的内窥式数字散斑干涉技术，实现微纳级别三维变形的高精度测量。其创新点在于利用波分复用技术与光纤布拉格光栅的特性，在内窥式数字散斑干涉光路中集成光纤迈克尔逊干涉系统，利用后者的输出对光纤光路进行反馈稳定控制并且对相移技术进行原位标定。本项目的研究可为内窥式数字散斑干涉技术的工程应用提供理论依据，提高我国尖端领域关键结构件的测试水平。

内窥式数字散斑干涉技术可以精密测量入口狭小的空腔或孔洞内表面的三维变形，扩展了传统数字散斑干涉技术的应用范围，在工程上具有显著的应用潜力。然而传统上该技术存在抗干扰能力弱、相位图质量差等问题，使其难以应用在工业现场。本项目通过探索全光纤数字散斑干涉技术的内窥测量理论和光纤自稳定理论，提出了基于新型测量模型的全光纤自稳定内窥式数字散斑干涉测量方法，并发展了多种相移方法、相位处理方法和光路结构，在此基础上研制了内窥式数字散斑干涉样机。同时通过建立数字散斑干涉角运动测量模型，实现了数字散斑干涉测量的精度评价。实验表明所研制的样机具有抗干扰能力强、相位图质量优、测量精度高等优点，具备现场应用能力。项目研究成果为内窥式数字散斑干涉技术的工程应用奠定了基础，为研制此类仪器提供了指导理论和参考方法。