IMEKO Event Proceedings Search

   

Page 470 of 977 Results 4691 - 4700 of 9762

Robert Schmitt, Philipp Jatzkowski, Markus Janssen, Guido Hüttemann
FLEXIBLE INSPECTION SYSTEM FOR SMALL SERIES PRODUCTION BASED ON IMAGE FUSION

In their pursuit for quality, companies in the production sector are confronted with the trend of ‘first time right on time’, thus requiring flexible production infrastructure for small series production. Regarding inspection tasksflexible metrology and highly flexible machine control structures are necessary. The primary goal of the presented project was the improvement, acceleration, and simplification of a machine vision inspection process of transparent free-form parts, such as automotive headlights. These parts have to be inspected for errors such as scratches, fingerprints, and dust. The inspection task is challenging, as common machine vision techniques such as line cameras and bright field or dark field illumination require dedicated setups for each product. The individual images are insufficient for the detection of non-conformances, thus requiring a different approach. The paper presents an approach using industrial standard machine vision and illumination strategies by applying sensor fusion, utilizing a single monochrome high resolution camera at different time intervals with different illumination. The project’s secondary goal was the flexibilisation of the machine’s control system by implementing a multi agent system replacing the existing programmable logic control architecture. The use of multi agent systems offers an innovative approach by splitting the responsibility of the accomplishment of tasks whilerelying on constant interaction among the agents to fulfil the production task.

Marta Wisniewska, Sabina Zebrowska-Lucyk
THE PROBLEM OF ACCURACY IN ROUGHNESS MEASUREMENT WITH THE USE OF THE FORM MEASURING MACHINE TALYROND 365

Accuracy of roughness parameters measured with Talyrond 365 was examined with comparison to the results received with the Form Talysurf PGI 830. The research has shown that there are several limitations of measurement method and software as well, while measuring with the Talyrond 365. Also, there are significant differences between results acquired with machines under comparison. The reasons for observed dissimilarities were discussed.

Siegfried Schmalzried, Holger Schmitz, Marcel Zimmermann
A FLEXIBLE AND, ROBUST 3D COORDINATE MEASUREMENT SYSTEM BASED ON WHITE LIGHT INTERFEROMETRY FOR CALIBRATIONOF INDUSTRIAL SYSTEMS

The demand on the precision of machine tools is steadily increasing. In this context, the intrinsic accuracy of the machine tools is no longer sufficient. Nowadays volumetric compensation is applied to minimize the errors of the tool center point.
This paper presents a new, flexible, high precision coordinate measurement system which also offers a great automation potential. Its principle is based on white-light interferometry. The system measures the distance between an emitter and minimum three reflectors. The position of the emitter with respect to the reflectors is determined via multilateration. Therefore, environmental conditions need to be measured and effects like thermal expansion needto be compensated by software. The mathematical and physical models for this compensation have been developed and applied to the system.
Measurements were done under workshop conditions and the results show that the precision of µ-GPS sy stem is comparable to nowadays measurement systems which are used for machine calibrations. Additionally the µ-G PS system allows a high precision 3-dimensional determination of the position. The calibration process can be done fully automated which is completely new in this kind of applications.

Xi Zhang, Laiwei Li, Junyi Yang
VISION BASED 3D MEASUREMENT AND GUIDING SYSTEM FOR REMOTELY OPERATED UNDERWATER VEHICLE

Remotely operated underwater vehicles (ROV) equipped with manipulator have been used for underwater operation increasingly. The ROV is usually operated manually with the aid of underwater camera to approach and grasp a target by its manipulator. Due to the low quality of underwater imaging, it is quite difficult for the human operator to determine the accurate distance and orientation between the ROV and the target interested. This paper presents an idea of developing an automatic 3D measurement and guiding system for ROV in an effort to facilitate this process. Based on structure-light triangulation principle, dual laser line and a camera are utilized to calculate the position and orientation of a cylindrical target. The measurement model considering refraction compensation and system calibration method is proposed. A prototype measurement system is designed and tested in a simulated underwater environment by a glass water tank. The experiments showthat the proposed system is feasible to determine the position and orientation of the target automatically on an accurate and efficient manner.

Leonid Sokolov
A HIGH-STABLE PRESSURE SENSOR BASED ON A SOI HETEROSTRUCTURE AND MEMS TECHNOLOGY FOR AN INTELLIGENT INSTRUMENTS

The time stability of pressure transducers is a necessary condition which provides the measurement and computation of ? flight data by an aircraft computer with required accuracy.
As compared with Weston Aerospace up-to-date highstable electromechanical pressure transducers, which use a resonance effect in a vibrating cylinder, semiconductor microelectromechanical sensors (SMEMS) have advantages in possible integration with a signal microprocessor circuit and in group manufacturing based on advanced MEMS technologies.
Honeywell is known to be conducting efforts in replacing electromechanical sensors with microelectromechanical ones in an aircraft flight data system.
Electrical p-n junctions in conventional silicon sensors are prerequisites for the time instability of sensors and an aircraft flight data measurement system as a whole. Conventional micromechanical piezoresistive sensors, which contain electric p-n junctions, have a limited operational temperature range due to the exponential dependence of reverse current from the p-n junction temperature as known in the semiconductor physics I0 ~ ni² ~ exp[-Δ EF/(k T)].
The capabilities of measurement error correction using microprocessor techniques for transfer characteristic linearization, temperature compensation and other parameters become significantly complicated due to the instability of the transfer characteristic of conventional SMEMS.
The developed concept, which eliminates the usage of p-n junctions in SMEMS, forms the basis for the proposed solutions and the principles of developing integral high-stable SOI-based membrane-type pressure sensors with a monolithic tensoframe.

Damian 3mierzchalski, Michal Wieczorowski
SIMPLE SCRATCH METHOD FOR INDUSTRY AND FOR TEACHING

It’s requested for many products to make a good aesthetic impression. This feeling cannot be permanent of course, but manufacturer takes care of a scratch-resistance coating, as surface appearance is one big part of this impression. The paper discusses new method for the scratch test, as an answer to the industry need for the technique that is quick, reliable and economically acceptable. Hence, new test stand was designed to improve existing methods for economical aspect especially. Construction of this instrument is described. Discussion of strong points is presented but also a list of weaknesses and all factors that were neglected is given.
To prove reliability of this test stand some experiments were carried out. All results were verified using a measurement system to inspect surface roughness and contour. Every scratch was evaluated with this system before the load application on the specimen (pre-scan). Then all scratches were measured at several cross-sections – one cross-section for each load.
New method was compared to the one described in ISO 19252 standard for determining the scratch properties of plastics under defined conditions. Also the instrument itself was compared to the advance scratch tester CETR-UMT. In the last section all planned modifications of this tester are described, considering adjustment to industry needs and flexibility for didactic use at technical schools and universities.

Orest Serediuk, Vitaliy Malisevych, Zygmunt Warsza
INVESTIGATION OF THE METROLOGICAL CHARACTERISTICS OF THE NATURAL GAS FLOW RATE STANDARD BASED ON VARIABLE PRESSURE DROP FLOWMETER

The analysis of existing in World practice flow rate measurement standards for calibration of the gas flow and volume measuring devices for operating conditions is carried. A new idea of the design the flow rate measurement standard dedicated for calibration meters and flow meters of natural gas is considered. It apply the variable pressure drop method for measuring the flow rate and volume of gas using the diaphragm as the constriction device. Design features of standard and its calibration with use of the standard flow rate measuring bell-type device are given.
The numerical modelling of coefficients, which determine the metrological parameters of flow rate measurement standard during its calibration and work, is conducted. The zones of the improved stability of standards flow rate coefficient values are established. The extended uncertainties of flow rate measurement standard during calibration and working are estimated.

Mitul Tailor, Punnu Phairatt, Jon Petzing, Michael Jackson, Rob Parkin
REAL-TIME SURFACE DEFECT DETECTION AND TRACEABLE MEASUREMENT OF DEFECT IN 3D

In recent years, there has been an increased emphasis for quality control in the manufacturing sector. Many manufacturing processes have become fully automated resulting in high production volumes. However, this is not necessarily the case for inspection of aerospace surface defects. Volume measurement of defects is one of the key elements in quality assurance in order to determine the pass or failure of certain manufactured parts within this industrial sector. Existing human visual analysis of surface defects is qualitative and subject to varying interpretation. Noncontact 3D measurement should provide a robust and systematic quantitative approach for surface defect analysis. Instrument native software processing of 3D data is often subject to issues of repeatability and may be non-traceable in nature, leading to significant uncertainty about data quantisation and representation. This is compounded by a lack of traceable surface defect standards and softgauges with which to test the instruments and software respectively.
This research is concerned with the development of novel traceable sub-millimetric surface defects produced using a Rockwell hardness test instrument on flat, single curvature (SC), and double curvature (DC) metal plates, and the development of a novel robust, repeatable, mathematical solution for automatic defect detection and characterization. This is then extended to a surface defect on an aerofoil that is measured in real-time and characterized using the novel algorithm. The results show that the new surface defect detection and quantification is more robust, efficient, and repeatable than existing solutions.

Franc Cus, Uros Zuperl
ADAPTIVE NETWORK BASED INFERENCE SYSTEM FOR ESTIMATION OF SURFACE ROUGHNESS IN END-MILLING

This paper presents a new approach for surface roughness (Ra) prediction during milling by using dynamometer to measure cutting forces signals and cutting conditions. End milling machining process of hardened die steel with carbide end mill, was modeled in this paper using the adaptive neuro fuzzy inference system (ANFIS) to predict the effect of machining variables (spindle speed, feed rate and axial/radial depth of cut) on surface roughness. In this contribution we also discussed the construction of a ANFIS system that seeks to provide a linguistic model for the estimation of surface roughness from the knowledge embedded in the neural network. The predicted surface roughness values determined by ANFIS were compared with experimental measurements. The comparison indicates that the performance of this method turned out to be satisfactory for evaluating Ra, within a 6% mean percentage error and 96% accuracy rate.

Wojciech Plowucha
SIMPLIFIED ALGORITHM OF COORDINATE MEASUREMENTS UNCERTAINTY EVALUATION

Long-lasting works on the ISO 15530 series can be a proof for complexity of uncertainty evaluation of coordinate measurements for different characteristics defined according to the rules of geometrical product specification (GPS). There are two most acknowledged and commonly accepted methods. First is described in the document ISO 15530-3:2011 which provides in detail the procedure of uncertainty evaluation with the use of calibrated workpiece or measurement standard. Second procedure is based on the use of computer simulation that is known from many imeko_proceedings and mentioned in ISO/TS 15530-4:2008.
The author is one of the elaborator of the methodology and the software (EMU-CMMUncertaintyTM) which makes possible evaluation of the measurement uncertainty for bridge and horizontal arm CMMs. Some details concerning the software operation have been published. The software is developed with assumptions some of which are similar as in the method using the computer simulation. The most important assumption is that the uncertainty of measurement for particular characteristic (size, dimension, form, orientation, location and run-out) is calculated with the formula describing the characteristic as a function of differences of coordinates of characteristic pointsof the workpiece (the generality condition).
For easier understanding of the methodology a simplified version was developed which includes in the uncertainty budget just the MPEE instead of the geometrical errors and probing head errors of the CMM. Of course, this assumption gives overestimated uncertainty values but enables the sensitivity analysis. The paper includes some interesting cases of the sensitivity analysis.

Page 470 of 977 Results 4691 - 4700 of 9762