Showing papers by "Paolo Chiariotti published in 2018"

Smart quality control station for non-contact measurement of cylindrical parts based on a confocal chromatic sensor

Abstract: In modern digital factories, in-line quality control on 100% of production has become a key strategy to keep production processes and products under control. The real time and early identification of deviations and trends, performed at the single process level, prevents generation of defects and their propagation to down-stream processes, enabling the entire manufacturing system to perform early detection of process deviations and self-adaptation to different conditions. This is done to approach the zero-defect target aimed for by the manufacturing sector.

High-Accuracy Dimensional Measurement of Cylindrical Components by an Automated Test Station Based on Confocal Chromatic Sensor

Abstract: This paper presents the design and characterization of a test station for high-accuracy dimensional measurement of cylindrical components; it is conceived for quality control of turned parts. The system is based on a confocal chromatic sensor and a four degree of freedom scanning system. The station is capable of smart behaviors, which allow to keep measurement uncertainty under control: in particular self-centering of the confocal sensor inside the cylindrical part under inspection, self compensation of temperature effects and self calibration check. Results show how the test station can achieve uncertainty in the range of 10 μn.

Smart measurement systems for Zero-Defect Manufacturing

Abstract: The paper introduces the system architecture developed within the GO0DMAN project integrating process and quality control for multi-stage manufacturing plants. It shows how it fits the requirements set for the development of zero defect manufacturing. Focus is put on the quality control systems, designed to exhibit smart behaviors, aiming to enhance their performance in varying conditions. Two examples of these inspection tools are presented, one for accurate measurement of internal dimensions of turned components, the other for vibration based diagnosis of a fan using Neural Network on chip.

3D Digital Image Correlation for vibration measurement on rolling tire: procedure development and comparison with Laser Doppler Vibrometer

Abstract: Noise generated from rolling tire is strictly related to vibrations caused by the impacts of tread blocks on the road surface. Performing vibration measurements on rolling tires is a quite complex task and non-contact methods should be exploited. Laser Doppler Vibrometer (LDV) is the technique that has been mainly used so far, but it has some disadvantages, among which the measurement duration represents the main issue. Digital Image Correlation (DIC) could represent an appealing alternative for this kind of measurement. Recent developments in Digital Image Correlation combined with the modern fast cameras could represent an innovative instrument for vibration measurement at high frequency (up to about 1000 Hz depending on rolling speed). This paper analyses the possibility of using 3D DIC for vibration measurement on rolling tire by a direct comparison with LDV. The advantages and disadvantages of both the techniques are highlighted along the paper by analysing data of an impact test (static case) and a rolling measurement.

Preliminary assessment of Photogrammetric Approach for detailed dimensional and colorimetric reconstruction of Corals in underwater environment

Abstract: The use of 3D scan technologies to provide 3D color models of some bio-constructor organisms without removing them from the sea represents a valuable contribution for the preservation of current marine flora and fauna. The necessity to perform accurate measurements of volume, surface area and other morphometric characteristics is to increase the knowledge about the habitat-forming species. In this way, it is possible to describe the modification they made to the seabed topography, to monitor their shape modification according to local environmental conditions and evaluate 3D structure and color of some species sensitive to climate changes. The necessity of working in an environment characterized by different light conditions and particulate concentrations, the need of having high-performance sealing and, last but not least, the portability guarantee have limited the range of possible measurement techniques among those available for 3D shape reconstruction. Within this context, the idea underlying this research activity is to adopt photogrammetric technique for underwater surveys. In particular, a comprehensive and detailed analysis of a small object in and outside-water is performed in lab-scale tests by means of two different camera lenses, to pinpoint the effectiveness and the weakness of the solution identified. Another contribution of this paper is the uses of a color correction algorithm in order to correct the scene illumination, improving the 3D reconstruction of the detected objects. It is shown the capability of the algorithm to solve the color mismatch problem in multi-view color images. Results show the 3D models with details very well reconstructed both in and outside-water. The image pre-processing step drastically improve the matching points recognition and the reconstruction of the whole object independently to environmental illumination changes.

Multi-Physical Signature Analysis of Induction Machines under Unbalanced Supply Voltage

Abstract: This paper investigates the effect of voltage-unbalance fault on current, vibration, acoustic noise and instantaneous power of an open-loop-controlled 1/3 HP and a closed-loop controlled 3 kW induction machine drive. Experimental tests are performed in the form of run-ups and the results are plotted as colormaps to visualize the effect of the unbalance in a large speed range. Based on the observation of these plots, the relevant orders are tracked to compare their evolution with speed, load and unbalance severity, emulated by an increasing resistance inserted on one phase up to the open-phase fault case. It turns out that the analysis of the computed instantaneous power and the estimated RMS current is more suited for a reliable diagnosis in all cases.

A Discrete-Continuous Method for Predicting Thermochemical Phenomena in a Cement Kiln and Supporting Indirect Monitoring

Abstract: Thermochemical phenomena involved in cement kilns are still not well understood because of their complexity, besides technical difficulties in achieving direct measurements of critical process variables. This article addresses the problem of their comprehensive numerical prediction. The presented numerical model exploits Computational Fluid Dynamics and Finite Difference Method approaches for solving the gas domain and the rotating wall, respectively. The description of the thermochemical conversion and movement of the powder particles is addressed with a Lagrangian approach. Coupling between gas, particles and the rotating wall includes momentum, heat and mass transfer. Three-dimensional numerical predictions for a full-size cement kiln are presented and they show agreement with experimental data and benchmark literature. The quality and detail of the results are believed to provide a new insight into the functioning of a cement kiln. Attention is paid to the computational burden of the model and a methodology is presented for reducing the time-to-solution and paving the way for its exploitation in quasi-real-time, indirect monitoring.

Experimental acoustic modal analysis of an automotive cabin: challenges and solutions

Abstract: In this paper, a full Acoustic Modal Analysis (AMA) procedure to improve the CAE predictions of the car interior noise level is proposed. Some of the challenges that can be experienced during such an analysis are described and new solutions to face them are proposed. Particular AMA challenges range from the arrangement of the experimental setup to the post-processing analysis. Since a large number of microphones are needed, a smart localization procedure, which automatically determines the microphone three dimensional (3-D) positions and dramatically reduces the setup time, is presented herein. Furthermore, the need for a large number of sound sources spread across the cavity to assure a homogeneous sound field makes modal parameter estimation a nontrivial task. Traditional modal parameter estimators have indeed proven not to be effective in cases where many input excitation locations have to be used. Hence, a more suitable estimator, the Maximum Likelihood Modal Model-based (ML-MM) method, will be employed for such an analysis.