输电塔架承载变形的三维光学测量

Measurement on structural deformation of load-bearing power transmission tower based on 3D optical method

考虑输电塔架结构复杂,需要做承载变形真型实验来检测塔架实际承载能力的问题,本文提出了一种三维全场变形光学测量方法来解决塔架真型试验中存在的大尺寸、大变形、多测点、三维变形、塔架承载形态保持时间短等测量难点。该方法基于工业近景摄影测量技术重建单个状态下塔架测点的三维结构,利用具有身份信息的人工标志点来实现不同状态测量结果的对齐。通过跟踪固定在塔架上的变形点,计算相应部位的位移来获取真型塔架在不同负载下的整体变形。精度评估实验表明,提出的方法测量精度优于0.1mm/4m;真型实验显示,测量结果能够为塔架结构力学性能分析和改进塔架设计提供有价值的参考数据。该方法具有现场工作量小、不干扰测量对象、量程弹性大等优点,能够满足各型塔架三维变形测量对效率和精度的要求。

The actual load-bearing capacities of Power Transmission Towers（PTTs） should be estimated by a real-scale model experiment due to their complex structures,therefore an optical full-field 3D deformation measurement method is proposed to overcome the difficulties of large-scale,large-displacement,3D deformation,rapid multi-point measurement in PTT real-scale model experiments.Based on close-range photogrammetry technology,this method utilizes specialized markers as measured targets to reconstruct the 3D coordinates of those pre-pasted artificial targets through analyzing the captured photo-set in each epoch,then it conducts the coordinate system global registration according to un-movable targets.By tracking and comparing the 3D coordinates of the deformable targets between different epoches,the 3D load-deformation diagram of the PPT stucture is obtained.Acceptance experiment results indicate that the accuracy of this method could reach about 0.1 mm/4 m and real-scale model experiments show the proposed method could meet accuracy and efficiency requirements of PPT load-deformation measurement.Comparing with traditional deformation sensors,the proposed method can satisfy measuring requirements of non-contact（non-interfere）,on-spot,high precision,rapid speed,strong anti-jamming and stabilization.