Fastener identification and assembly verification via IR tracking

Abstract

Purpose

The purpose of this paper is to create an assembly verification system that is capable of verifying complete assembly and torque for each individual fastener.

Design/methodology/approach

The 3D position of the tool used to torque the fastener and the assembly pallet will be tracked using an infrared (IR) tracking system. A set of retro‐reflective markers are attached to the tool and assembly while being tracked by multiple IR cameras. Software is used to triangulate the relative position of the tool in order to identify the fastener being torqued. The torque value is obtained from the tool controller device. By combining the location of the tool and the torque value from the tool controller, assembly of each individual fastener can be verified and its achieved torque recorded.

Findings

The IR tracking is capable of tracking within 2‐3 mm for each tracking ball, with a resulting practical resolution of 24 mm distance between fasteners while maintaining 99.9999 per cent reliability without false positive fastener identification.

Research limitations/implications

This experiment was run under simulated assembly line lighting conditions.

Practical implications

By being able to verify assembly reliably, the need for manual torque check is eliminate and hence yield significant cost savings. This will also allow programming electric tools according in real time based on the fastener in proximity identification.

Originality/value

Currently, assembly verification is only done using the torque values. In automated assembly line, each process might involve fastening multiple fasteners. Using this system, a new level of assembly verification is achieved by recording the assembled fastener and its associated torque.

Citation

Rusli, L. and Luscher, A. (2012), "Fastener identification and assembly verification via IR tracking", Assembly Automation, Vol. 32 No. 3, pp. 262-275. https://doi.org/10.1108/01445151211244429