中文摘要：

基于弓高弦长法直径测量原理,设计开发了一套大外径高精度在线测量装置。该装置由测试系统和标定系统两部分组成。测试系统主要由3个高精度激光位移传感器组成,标定系统主要由2个已知直径尺寸的大圆盘组成。由标定系统完成测量系统弦长和初始弓高的标定,相对弓高由测试系统测出。该装置结构简单、操作方便。对装置的直径测量精度进行了仿真分析和实际测量实验分析。所得结果表明,大外径的测量精度小于5μm。

英文摘要：

An apparatus,being composed of a measuring system and a calibrating system,for online measuring large external diameter from chord length and bow altitude,was designed and developed.The measuring system was mainly composed of three displacement sensors,and the calibrating system was mainly composed of a large circular disk,the two different diameters of which were known.The chord length and the initial bow altitude were calibrated with calibrating system,and the relative bow altitude was measured by displacement sensors.This apparatus structure is simple,and its operation is convenient.Analyzing the measuring precision with simulation and real measurement test,it shows the measuring accuracy for large external diameter with this apparatus is superior to 5μm.