Eventos Anais de eventos
COBEM 2021
26th International Congress of Mechanical Engineering
EVALUATION OF CIRCULARITY MEASUREMENT THROUGH LIMAÇON APPROXIMATION AND A LIGHT DETECTION AND RANGING (LiDAR) SYSTEM
Submission Author:
Manoel Kolling Dutra , SC
Co-Authors:
Vinicius Conti da Costa, Bruno Ziegler Haselein, Filipe Barbosa Veras, Manoel Kolling Dutra, Tiago Pinto
Presenter: Vinicius Conti da Costa
doi://10.26678/ABCM.COBEM2021.COB2021-0943
Abstract
Pipelines are an important part in systems for production, transportation and consumption in the oil and gas industries. As the main objects of pipeline transport systems, pipes are subject to strict requirements for the quality of the manufacturing materials, production technology, coating quality, as well as their geometric and dimensional aspects. In order to provide inspection of pipes at all stages of logistical movement, it is necessary to find a measurement method that can quickly measure the inner pipe diameter and geometry in complex environments. However, it is not practical to align a rotary axis measurement system (MS) on the longitudinal axis of a cylindrical pipe with good accuracy, and subsequent measurements will not directly provide geometric errors, as circularity. So, if there is a small eccentricity in the MS positioning, the inner circle that this instrument aims to measure can be approximated by a geometry called limaçon. This approach results in a linear equation to identify the unknown measurement parameters, making trivial the process of determining the center and radius of the measurand. This study presents the evaluation of an active measurement system called Light Detection and Ranging (LiDAR) with a 360° rotation axis as MS and uses limaçon approximation to calculate the decentralization of the MS and the circularity error of the measurand. The experimental procedure includes positioning the LiDAR on a plane perpendicular to the axial axis of the measurand and capturing data in four positions, i.e., one with the MS approximately concentric to the measurand, and the others with offsets. In the sequence, the calculation of the circularity deviation by limaçon approximation and uncertainty measurement are performed to evaluate sources of uncertainty, such as resolution and Azimuth angle. In addition, the effect of several parameters, such as angular rate, angular speed and number of revolutions are evaluated, and the results are compared with those obtained through an articulated 3D measuring arm. The results indicate that the smallest circularity error occurs when the LiDAR is near to the center and the error due to the approximation in limaçon tends to zero when there is no eccentricity. However, the proposed approach is not suitable for large eccentricities. In addition, the lower the angular velocity of the LiDAR, the greater the measurement error due to a bigger point cloud measured in a single revolution when at low speed, which results in more surface details.
Keywords
Pipe Inspection, circularity measurement, limaçon approximation, LiDAR
