Ermitteln von Lagefehlern bei Einlippenbohrern/Determination of position errors in single-lip drills

Dieser Beitrag stellt eine berührungslose Messmethode zur Feststellung von Lagefehlern bei Einlippenbohrern vor, die auf der Verwendung eines Laser-Profilsensors basiert. Durch die Messung von Verlagerungen an mehreren Positionen entlang des langsam rotierenden Werkzeugschafts kann die Lage des Werkzeugs in Polarkoordinaten abgebildet werden. Das System bietet die Möglichkeit sowohl herstellungsbedingte Fehler als auch durch Bearbeitungskräfte und -momente verursachte Formänderungen des Werkzeugs nach verschiedenen Schnittwegen feststellen zu können.   This article introduces a non-contact measuring method, based on the use of a laser profile sensor to determine position errors in single-lip drills. By measuring displacements at several positions along the tool shaft with the machine spindle rotating slowly, the actual position of the tool can be mapped in polar coordinates. The system thus offers the potential to identify manufacturing-related errors as well as changes in the shape of the tool caused by machining forces and torques after different cutting paths.

High-precision width measurement method of laser profile sensor

Purpose Although a laser profile sensor (LPS) can be used to measure dimensions, the “shadow region” generally degrades the accuracy and precision of width measurements. The accuracy and precision of such measurements should be improved. Design/methodology/approach In this paper, the authors propose herein a technique that combines high dynamic range (HDR) imaging with logistic fitting. First, a HDR image is composed of several images acquired with different exposure times, which augments the grayscale of the object profile and significantly reduces overexposure. Next, the profile is fit to a logistic function, which provides accurate and precise edge coordinates. Finally, given the edge coordinates, the object width is calculated. Findings To verify the stability of this logistic algorithm, the authors simulate different noise conditions and different degrees of incomplete edge data. In addition, the progressiveness of the algorithm is demonstrated by comparing the results with those of other algorithms and with the height measurement. Furthermore, the suitability of the system is verified experimentally. Research limitations/implications Because of the limitation of the condition of laboratory, in the experimental section, this paper cannot represent perfectly the industrial situation. It makes this section limited in demonstration. Originality/value In this paper, the results show that the measurement accuracy and precision of the width is improved and exceeds that of the height measurement. The proposed HDR imaging method with logistic fitting may be applied to LPS width measurements, which should significantly aid the development of LPSs.

Integrating laser profile sensor to an industrial robotic arm for improving quality inspection in manufacturing processes

This paper investigates the integration of laser profile sensor to an industrial robotic arm for automating the quality inspection in manufacturing processes that requires a manual labour intensive work. The aim was to register the measurements from a laser profile sensor mounted on a six degrees-of-freedom robot with respect to the robot base frame. The registration is based on a six degrees-of-freedom calibration, which is an essential step for several automated manufacturing processes that require high level of accuracy in tool positioning and alignment on one hand, and quality inspection systems that require flexibility and accurate measurements on the other hand. The investigation compromises of two calibration procedures namely the calibration using a sharp object and the planar constraints. The solution of the calibration procedures estimated from both iterative and optimization solvers is thoroughly discussed. By implementing a simulation platform that generates virtual data for the two procedures with additional levels of noise, the six-dimensional poses are estimated and compared to the ground truth. Finally, an experimental test using a laser profile from Acuity mounted on Mitsubishi RV-6SDL manipulator is presented to investigate the measurement accuracy with four estimated laser poses. The calibration procedure using a sharp object shows the most accurate simulation and experimental results under the effect of noise.

Light Drone-Based Application to Assess Soil Tillage Quality Parameters

The evaluation of soil tillage quality parameters, such as cloddiness and surface roughness produced by tillage tools, is based on traditional methods ranging, respectively, from manual or mechanical sieving of ground samples to handheld rulers, non-contact devices or Precision Agriculture technics, such as laser profile meters. The aim of the study was to compare traditional methods of soil roughness and cloddiness assessment (laser profile meter and manual sieving), with light drone RGB 3D imaging techniques for the evaluation of different tillage methods (ploughed, harrowed and grassed). Light drone application was able to replicate the results obtained by the traditional methods, introducing advantages in terms of time, repeatability and analysed surface while reducing the human error during the data collection on the one hand and allowing a labour-intensive field monitoring solution for digital farming on the other. Indeed, the profilometer positioning introduces errors and may lead to false reading due to limited data collection. Future work could be done in order to streamline the data processing operation and so to produce a practical application ready to use and stimulate the adoption of new evaluation indices of soil cloddiness, such as Entropy and the Angular Second Moment (ASM), which seem more suitable than the classic ones to achieved data referred to more extended surfaces.