Konferenzbeiträge

Due to increasingly complex and automated manufacturing processes, the demands on the control parameters of these processes are also increasing. One parameter is the fill quantity of, e.g., liquids in production plants, whose precise determination is of ever-growing importance. Up to now, the exact level of determination under difficult conditions, such as high ambient temperatures, has been a particular challenge. This paper demonstrates a novel method by which an M-sequence UWB radar can determine levels of low-permittivity materials in small metal containers. For this purpose, hot melt is used as an example. Thus, the influence of large temperature differences on the long-term stability of level measurement can also be investigated. The measurements show that the level of hot melt can be measured to be long-term stable with an accuracy of better than 3 mm. Furthermore, the precise determination of the empty state is highly important for many applications. For this reason, this paper shows a method for determining the empty state without complex calibration procedures. For the empty level indication, an accuracy of up to 0.5 mm could be achieved for molten hot glue and 3% of the tank volume, independent of the shape or aggregate state of the medium.

Concentric tube continuum robots are a promising type of robot for various medical applications. Their application in neurosurgery poses challenging requirements for design and control that can be addressed by physics-informed data-based approaches. A prerequisite to data-based modeling is an informative, rich data set. However, limited access to experimental data raises interest in partially or entirely synthetic data sets. In this contribution, we study the application of generative adversarial networks (GANs) for data augmentation in a data-based design process of such robots. We propose a GAN framework suitable for curve-fitting to generate synthetic trajectories of robots along with their corresponding control parameters. Our evaluation shows that the GANs can efficiently produce meaningful synthetic trajectories and control parameter pairs that show a good agreement with simulated trajectories.

In this paper, we present a novel technique for stabilisation of widely wavelength modulated lasers (>100pm) over long time scales, where modulation depths exceed the spectral width of standard reference features, such as gas absorption lines, by over an order of magnitude. The technique operates by controlling the temporal separation between successive appearances of a gas absorption line on the up and down sweeps of a sinusoidal laser wavelength modulation waveform. The influence of the signal distortions introduced by the laser intensity modulation that are associated with laser diode injection current modulation are also addressed. The technique is applied to a range-resolved interferometric system interrogating a Mach-Zehnder interferometer operating in thermally stable conditions, using an absorption feature from a fibre-coupled gas cell as a reference. Proof-of-principle measurement results achieved using this technique are presented, demonstrating a notional fractional stability of 3.9×10−7 without further correction.

Die Einsatzmöglichkeiten von konventionellen Interferometersystemen sind oft aufgrund ihrer Baugröße eingeschränkt. Weiterhin stellen sie noch immer preisintensive, manuell gefertigte Präzisionsbaugruppen dar. Ihr Einsatz ist daher ökonomisch nur für Nischenanwendungen in der Hochtechnologie gerechtfertigt. Aus diesem Grund wird ein neues kompaktes Mikrointerferometer entwickelt, welches auf dem Michelson-Prinzip basiert. Die gesamte Baugröße dieses Mikrointerferometer beträgt 40 mm x 20 mm x 15 mm. Als Strahlteiler wird eine Strahlteilerplatte verwendet, der nicht auf beiden Seiten parallel ist, sondern einen Keilwinkel hat. Dadurch wird der Interferenzwinkel erzeugt. Außerdem sind beide Seiten mit Polarisationsbeschichtung und Entspiegelungsbeschichtung versehen. Zukünftig können die Beschichtungen auf eine große Platte vorbereitet werden und dann ist eine Massenfertigung für die Strahlteilerplatten möglich, sodass die Herstellungskosten dieser Strahlteilerplatten reduziert werden.

The use of high-strength structural steels brings great advantages in constructions regarding material requirements, weight reduction and productivity. Different steel grades within the S960 range are commercially available but not yet represented in Eurocode 3. The weldability of these steels is limited to smaller process windows to ensure the high material properties. In contrast to steels with moderate strength, there is a considerable risk of softening in the heat-affected zone causing a strength reduction of the connection. By now, the current EN 1993-1-12 only extends the design rules to cover steel grades up to S700. Therefore, the potential of these high-strength steels cannot be used to its full extent in structural engineering. This study, made within a steel application research project (FOSTA P 1507), deals with the weldability and load-carrying capacity of butt and fillet welded joints of S960QL and S960MC produced by gas-shielded metal arc welding. The influence of different bevel geometry, filler metal, and plate thicknesses was investigated. To extend the design rules up to S960, a need of an amendment was found for some combinations.