An Accurate Point-Based Rigid Registration Method for Laser Tracker Relocation
An Accurate Point-Based Rigid Registration Method for Laser Tracker Relocation
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DOI：
10.1109/tim.2016.2608560
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发表时间：
2017-02-01
影响因子：
5.6
通讯作者：
Chen, Ken
中科院分区：
文献类型：
--
作者：
Wan, An;Xu, Jing;Chen, Ken
激光跟踪仪广泛应用于大型构件的测量。在实际应用中，由于激光跟踪仪尺寸大、形状复杂，为了减小测量距离或避免遮挡，通常采用基于基准点的方法进行激光跟踪仪的重新定位。对于传统的重定位方法，期望许多基准点均匀地分布在整个测量体积中。但由于被测零件和夹具对光束的遮挡，基准点的数量和分布不能满足要求，导致定位精度不高。针对这一问题，提出了一种基于测量平差的搬迁方法。该方法首先考虑激光跟踪仪的非均匀性和各向异性特性，推导出与距离和方向相关的权重矩阵;然后进行测量平差，减小基准点的定位误差，从而减小重定位误差。仿真和实验验证了该方法的定位误差，结果表明，与传统的定位方法相比，该方法只需在狭窄的空间内分布较少的基准点，就能获得较高的定位精度，可应用于复杂环境下解决光束遮挡问题。
The laser tracker is widely used in a large component measurement. In practical application, due to the large size and complex shape, the laser tracker relocation is usually performed based on the fiducial points to reduce measurement distance or avoid occlusion. For a conventional relocation method, a lot of fiducial points are expected to be uniformly distributed in the entire measurement volume. However, the number and distribution of fiducial points cannot satisfy this requirement due to the light beam occlusion caused by the measured component and jig, resulting in low relocation accuracy. To solve this problem, we propose a survey adjustment-based relocation method. For this method, first, taking into account the inhomogeneity and anisotropy properties of laser tracker, the weighting matrix related to distance and direction is deduced; second, survey adjustment is performed to reduce the location error of a fiducial point, thereby reducing the relocation error. Simulations and experiments are carried out to verify relocation error, and the results show that compared with a traditional relocation method, our proposed method can achieve higher relocation accuracy only with fewer fiducial points distributed in a narrow space; thus, it can be applied in a complicated environment to solve the light beam occlusion problem.