三维（3D）微位移监测在大型飞机装配中起着至关重要的作用。本文提出了一种广泛适用的基于接近传感器的高精度在线3D微位移监测方法和系统，以及相应的原位校准方法，可应用于飞机装配过程中遇到的各种极端工作条件，如紧凑和遮挡的空间。首先建立了一个3D监测模型，仅基于接近传感器测量的一
维距离实现3D微位移监测，该模型涉及传感器外部参数，如测量原点（PBP）和单位位移矢量（UDV）。然后，结合空间变换原理和加权优化校准方法，获得高精度外部参数。最后，针对尾翼装配过程开展了校准和监测实验。PBP 的校准精度在X、Y 方向优于±10 μm，在Z 方向优于±2 μm，UDV 的校准精度优于0.07°。此外，3D微位移监测系统的精度可达到±15 μm。总体而言，本文为基于接近传感器的3D微位移监测的建模和校准提供了新的见解，并为飞机装配过程中紧凑空间内的几何测量提供了一种高精度、高效率、低成本的技术手段。

Three-dimensional (3D) microdisplacement monitoring plays a crucial role in the assembly of large aircraft. This paper presents a broadly applicable high-precision online 3D microdisplacement monitoring method and system based on proximity sensors as well as a corresponding in situ calibration method, which can be applied under various extreme working conditions encountered in the aircraft assembly process, such as compact and obstructed spaces. A 3D monitoring model is first established to achieve 3D microdisplacement monitoring based only on the one-dimensional distances measured by proximity sensors, which concerns the extrinsic sensor parameters, such as the probe base point (PBP) and the unit displacement vector (UDV). Then, a calibration method is employed to obtain these extrinsic parameters with high precision by combining spatial transformation principles and weighted optimization. Finally, calibration and monitoring experiments performed for a tailplane assembly process are reported. The calibration precision for the PBP is better than ±10 μm in the X and Y directions and ±2 μm in the Z direction, and the calibration precision for the UDV is better than 0.07°. Moreover, the accuracy of the 3D microdisplacement monitoring system can reach ±15 μm. In general, this paper provides new insights into the modeling and calibration of 3D microdisplacement monitoring based on proximity sensors and a precise, efficient, and low-cost technical means for performing related measurements in compact spaces during the aircraft assembly process.