The road temperature is used as an indicator for the winter maintenance service. Consequently, it should be determinated within a known measurement uncertainty. Investigations in road weather stations revealed inconsi...
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This paper presents traceable measurements of bending stiffness for standard optical SMF-28 fiber. Stiffness values were derived from force-displacement measurements, performed in a setup specifically designed for the...
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In this contribution we propose the incorporation of a diode laser stabilized to an ultrastable cavity (ORS) as a metrology laser within the interferometric length measurement system of a nanopositioning and -measurin...
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This paper presents a measurement technique which makes it possible to scan varying interference patterns by using the incremental procedure (forward-backward counting method). The essence of this procedure is that th...
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In this paper a force measurement system is discussed, among others its main application is for the flow rate measurement of conducting fluids by the method of Lorentz force velocimetry. The system is designed to meas...
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This paper describes a new metrological scanning probe microscope (SPM) for high-precision long-range measurement. For accurate measurements the position of the cantilever must be measured in addition to the torsion a...
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ISBN:
(纸本)0955308208
This paper describes a new metrological scanning probe microscope (SPM) for high-precision long-range measurement. For accurate measurements the position of the cantilever must be measured in addition to the torsion and bending. The solution realised is a combined detection system with a single laser beam. This system has been equipped with a special interferometer system and a quadrant photodiode. The scanning motion can be provided by a coordinate positioning and measuring system of the highest accuracy, such as the nanopositioning and nanomeasuring machine (NMM) [1] with a measuring range of 25 mm × 25 mm × 5 mm. With the metrological SPM it is possible to calibrate pitch, step-heights and structure width.
In order to further improve the metrological properties of weighing systems based on the principle of electromagnetic force compensation (EMFC) as well as quality assurance, it is necessary to determine the parameters...
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ISBN:
(纸本)9781618390219
In order to further improve the metrological properties of weighing systems based on the principle of electromagnetic force compensation (EMFC) as well as quality assurance, it is necessary to determine the parameters relevant for the dynamic operation, such as measurement time and controller behavior. This determination is carried out by loading the balance system and observing the indication. Typically this is done by a load changer using different metrological weights. This method is inevitable if metrological traceability is required. However, the conventional procedure of load changing also entails several disadvantages. The number of possible load changes per unit time is limited and the force characteristic during loading is usually unknown and relatively difficult to reproduce or manipulate. Furthermore the fast and sudden exchange of the weights causes mechanical vibrations and a movement of the surrounding air, both of which act as additional disturbances. In this paper we propose an alternative loading method, with which these shortcomings can be improved and compare it to a conventional system. This method is based on loading the weighing system in a defined manner using a Lorentz-force, allowing the tester to generate a known, virtually arbitrary force characteristic during loading. It is shown that the Lorentz-force generated load represents a practical alternative to classical weights, offering advantages in reproducibility, dynamics and ability to be automated. Since the proposed method applies a known Lorentz-force to the weighing system it becomes possible to exactly determine the relationship between the force acting on the weighing pan and the resulting behavior of the weighing system.
The use of high-tech plastics in the field of mechanical engineering is increasing dramatically. The time-dependent change of strain Ε(t) during constant load (viscoelasticity, creeping) is a fundamental property of ...
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ISBN:
(纸本)9781615675937
The use of high-tech plastics in the field of mechanical engineering is increasing dramatically. The time-dependent change of strain Ε(t) during constant load (viscoelasticity, creeping) is a fundamental property of plastics and exact knowledge of these properties is required for the design of plastic parts. A novel high-resolution materials testing device is presented in this paper. It offers reaction-free interferometric measurement of the viscoelastic behaviour of plastics at a constant bending load. The resolution of the deflection is 1 nm. Therefore, unlike the three point bending test described in the ISO 899-2:2003 standard [1], the device is suitable for the measurement of viscoelasticity Ε(t) at very small strain values (Εmax
In this paper a mechatronic model for an electromagnetic-force-compensated (EMC) load cell is presented. Designed in MATLAB® Simulink® the model consists of four main modules: a rigid-body model delineating ...
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ISBN:
(纸本)9781618390219
In this paper a mechatronic model for an electromagnetic-force-compensated (EMC) load cell is presented. Designed in MATLAB® Simulink® the model consists of four main modules: a rigid-body model delineating the mechanical behaviour of the load cell, an analytical model characterising the electrodynamic actuator consisting of a voice coil and a permanent magnet, a characteristic curve modelling the position detector, and a continuous or discrete model describing the operation of the controller. Optimization of the mechanical, electromagnetic and controller components can be performed using this model;furthermore experiments can be performed to determine the sensitivity of the complete system to changes of defined parameters.
This paper discusses an optical position sensor which can be used in balances based on the principle of electromagnetic force compensation (short used EFC) for example. Other applications are zero point detection as w...
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ISBN:
(纸本)9781618390219
This paper discusses an optical position sensor which can be used in balances based on the principle of electromagnetic force compensation (short used EFC) for example. Other applications are zero point detection as well as high precision positioning in the range of ± 200 μm. The position sensor consists of two infrared-LED (IR-LED) which illuminate a single photodiode via an aperture. The aperture is movable and performs a shadowing of the beams, thus shadowing changes due to the position of the aperture. The photodiode detects light from both LED. Both light sources have to be modulated and phase shifted to distinguish them in the photodiode signal. The evaluation of the position of the aperture is done by demodulating the received signal. A major advantage of this method is that the aperture's operating point is in the centre of the beams. Hence higher sensitivity is achievable and the beams can be focused onto the photodiode. Furthermore standard components are used and thus expensive differential photodiodes are no longer necessary.
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