Complete list of publications

Tiltmeters with nanorad resolution in a large measurement range of ±9 mrad (±0.5˚) and a very good linearity have been developed at the Technische Universität Ilmenau in the recent years. The working principle bases on the measurement of tilt-dependent lateral forces, which act on a hanging force-compensated weigh cell (precision balance). The disadvantage is the relatively complex design of the weigh cell mechanics, the large dead weight and the high manufacturing costs. - For that reason a simplified tiltmeter was developed. It only consists of two components: a monolithic pendulum mechanics and an optical position sensor. State of the art pendulum tiltmeters contain several components that are linked by screwed, clamped or glued connections. This can limit the long-term-, temperature- or humidity stability of the tiltmeter. - The position sensor achieves a standard deviation of ˜50 pm at a measuring frequency of 10 Hz. The length of the pendulum amounts to 0.1 m, its mass is ˜62 g. With this combination, the theoretical standard deviation of the tilt measurement should result to ˜0.6 nrad at 10 Hz measuring frequency and was approved by measurements. The measurement range of the new monolithic tiltmeter amounts ˜±2 mrad.

The aspects of design and operation of information measuring subsystem of Cyber-Physical System of coke and chemical plant are considered. This subsystem of mass parameters definition, based on industrial internet, provides coded remote access aiming at the execution of both weighing and verification metrological operations by using an embedded multivalued mass measure. To ensure the quality and reproducibility of Cyber-Physical System a remote access on the basis of TCP/IP protocol to balances was studied and developed. Installation was equipped with the standard built-in mass measure that enabled to perform in-place operations of metrological checking, verification, calibration etc. not interrupting the production cycle.

Optical profilers are mature instruments used in research and industry to study surface topography features. Although the corresponding standards are based on simple step height measurements, in practical applications these instruments are often used to study the fidelity of surface topography. In this context it is well-known that in certain situations a surface profile obtained by an optical profiler will differ from the real profile. With respect to practical applications such deviations often occur in the vicinity of steep walls and in cases of high aspect ratio. In this contribution we compare the transfer characteristics of different 3D optical profiler principles, namely white-light interferometry, focus sensing, and confocal microscopy. Experimental results demonstrate that the transfer characteristics do not only depend on the parameters of the optical measurement system (e. g. wavelength and coherence of light, numerical aperture, evaluated signal feature, polarization) but also on the properties of the measuring object such as step height, aspect ratio, material properties and homogeneity, rounding and steepness of the edges, surface roughness. As a result, typical artefacts such as batwings occur for certain parameter combinations, particularly at certain height-to-wavelength ratio (HWR) values. Understanding of the mechanisms behind these phenomena enables to reduce them by an appropriate parameter adaption. However, it is not only the edge artefacts, but also the position of an edge that may be changed due to the properties of the measuring object. In order to investigate the relevant effects theoretically, several models are introduced. These are based on either an extension of Richards-Wolf modeling or rigorous coupled wave analysis (RCWA). Although these models explain the experimental effects quite well they suffer from different limitations, so that a quantitative correspondence of theoretical modeling and experimental results is hard to achieve. Nevertheless, these models are used to study the characteristics of the measured signals occurring at edges of different step height compared to signals occurring at plateaus. Moreover, a special calibration sample with continuous step height variation was developed to reduce the impact of unknown sample properties. We analyzed the signals in both, the spatial and the spatial frequency domain, and found systematic signal changes that will be discussed. As a consequence, these simulations will help to interpret measurement results appropriately and to improve them by proper parameter settings and calibration and finally to increase the edge detection accuracy.

Eine praktische Durchführung, realisiert mit kommerzieller Software, zur Ermittlung der Unsicherheit einer numerischen thermischen Simulation mit FEM wird in diesem Beitrag vorgestellt. Hintergrund davon ist die Prognosefähigkeit dieses FEM-Modells anhand seiner Validierung mit Messungen unter Berücksichtigung ihrer Reproduzierbarkeiten zu Berechnen und daraus die Güte oder Wahrscheinlichkeit der Übereinstimmung von Mess- und Simulationsergebnissen unter Berücksichtigung ihrer Unsicherheiten in drei unterschiedlichen Szenarien zu finden, mit unbekannten Messergebnissen, mit bekannten Messergebnissen und nicht vollständig bekannten Randbedingungen und mit bekannte sowohl Messergebnissen als auch Randbedingungen. Der Vergleich der Ergebnisse wird mit einer Erweiterung der Area-Metrik Methode gemacht.