A machine vision system for the braid angle measurement of tubular braided structures

Abstract

Two-dimensional braided composite materials consist of an impregnated and cured braided fiber structure. The braid angle, which describes the orientation of fibers on the mandrel, affects the material properties of the composite part. Furthermore, braid production is often inaccurate, requiring quality assurance measurements of the fiber orientation. In this study, a frequency domain machine vision algorithm was applied to tubular braided preforms to measure fiber alignment during production. Several approaches to compensate for the tubular mandrel shape were tested and the fiber distribution in both the spatial and frequency domains was compared. The developed machine vision system allowed braid angle measurements to be made in real-time and in-line during the braiding process. The integration of such a system eliminates the need to make manual quality assurance measurements of the braided fiber structure, it further automates the braiding process, and it decreases production error.

A Cooperative Mobile Robot and Manipulator System (Co-MRMS) for Transport and Lay-up of Fibre Plies in Modern Composite Material Manufacture

“…The error of the vision system was reduced to 0.23 degree approximately. In comparison, the detection error was around or below 1 degrees by derived fibre reflection model in [22] and the frequency domain machine vision algorithm in [48] showed around 5 degrees error for braid angle measurement. This indicated that the proposed machine vision system with two-step strategy can achieve high accuracy in fibre orientation detection.…”

Improving two-dimensional braided composite tensile properties by including low angle yarn twist: Production, experimental verification, and modeling

“…Kevlar 49 (DuPont Inc.), a synthetic polyaramid yarn, has been used extensively for various textile composite applications, including braiding. 16,23 BioMid (BioMid Fiber, Burnaby, BC, Canada), a regenerated cellulose yarn, has only recently been used in TBCs. 5,24 Both Kevlar 49 and BioMid yarns are supplied as continuous multifilament yarns.…”

“…The braid angle selected was far from the jamming limit of the yarns, and thus the reduction in yarn area had no impact on the braid angle beyond typically measured variability of 3° to 5°. 23 As well, each specimen was measured prior to testing. It was found that the measured wall thickness increased based on the manufacturing technique.…”

Surface parameters measurement for braided composite preform based on gray projection

“…At present, several automatic measurement methods 23,24 have been proposed for 3D braided composites preforms. For the parameter measurement of 2D braided preforms, Hunt and Carey 25 applied a frequency domain method to achieve automatic real-time of 2D braided preform. This method is more suitable for the fabric images with high contrast between fiber bundle and background and is easy to be affected by the contrast of braided axis.…”