title: Configuration Analysis of the ERS Points in Large-Volume Metrology System.
abstract: In aircraft assembly, multiple laser trackers are used simultaneously to measure large-scale aircraft components. To combine the independent measurements, the transformation matrices between the laser trackers' coordinate systems and the assembly coordinate system are calculated, by measuring the enhanced referring system (ERS) points. This article aims to understand the influence of the configuration of the ERS points that affect the transformation matrix errors, and then optimize the deployment of the ERS points to reduce the transformation matrix errors. To optimize the deployment of the ERS points, an explicit model is derived to estimate the transformation matrix errors. The estimation model is verified by the experiment implemented in the factory floor. Based on the proposed model, a group of sensitivity coefficients are derived to evaluate the quality of the configuration of the ERS points, and then several typical configurations of the ERS points are analyzed in detail with the sensitivity coefficients. Finally general guidance is established to instruct the deployment of the ERS points in the aspects of the layout, the volume size and the number of the ERS points, as well as the position and orientation of the assembly coordinate system.
authors.affiliation: The State Key Laboratory of Fluid Power Transmission and Control, Zhejiang University, Hangzhou 310058, China. leopard85@zju.edu.cn.
authors.forename: Zhangjun
authors.initials: Z
authors.lastname: Jin
authors.affiliation: The State Key Laboratory of Fluid Power Transmission and Control, Zhejiang University, Hangzhou 310058, China. yuppy@zju.edu.cn.
authors.forename: Cijun
authors.initials: C
authors.lastname: Yu
authors.affiliation: The State Key Laboratory of Fluid Power Transmission and Control, Zhejiang University, Hangzhou 310058, China. ljxiong@zju.edu.cn.
authors.forename: Jiangxiong
authors.initials: J
authors.lastname: Li
authors.affiliation: The State Key Laboratory of Fluid Power Transmission and Control, Zhejiang University, Hangzhou 310058, China. ylke@zju.edu.cn.
authors.forename: Yinglin
authors.initials: Y
authors.lastname: Ke
keywords: aircraft assembly; configuration of the ERS points; large-volume metrology; layout of the ERS points; transformation matrix errors