An electrostatic force balance as a primary standard to measure high laser power by a multiple reflection system. - In: 36th ASPE Annual Meeting 2021, (2022), S. 11-15
Neuartige Methode zur Bestimmung der Schwerpunkhöhe von Massenormalen :
Novel method for determining the center of gravity height of mass standards. - In: Sensors and Measuring Systems, (2022), S. 204-207
The most precise vacuum mass comparators have a resolution of 0.1 μg, operating at one kilogram [1]. The resolution represents a relative difference in weight of the artifacts of 1×10^(-10). Small deviations in the height of the center of gravity of the mass artifacts lead to a systematic error of the measurement results. For example a difference in the height of the center of gravity of 1 cm in Earth's gravitational field causes a relative systematic uncertainty contribution of 3.2×10^(-9). Therefore, it is important to know the artifacts' heights of the center of gravity. This paper introduces a novel approach to measure the height of the center of gravity of high-sensitive mass artifacts. The method allows to compare the mass of artifacts of unusual shape, inhomogeneous composition or hollow mass standards with uncertain internal geometry. For the determination, the mass artifacts are placed on three load cells, arranged at an angle of 120˚. The load cells are attached to the base, which stands on a high-precision tilt table [2]. The difference in force with variation of the inclination angles allows to calculate the height of the center of gravity of the artifacts. To verify the method, various mass standards of known geometry and composition are measured as described. In the end, the comparison between theoretically determined values and the measurement results shows a good agreement of the method.
https://ieeexplore.ieee.org/document/9861899
Concept of a monolithic stiffness-compensated mechanism for high-resolution force sensors. - In: Sensors and Measuring Systems, (2022), S. 461-464
Monolithic compliant mechanisms with concentrated compliances are often used in high-resolution force sensors and precision balances. Since the measurement resolution is vastly limited by the bending stiffness of the compliant joints, the thinnest part of the joints is reduced to down to 50 µm. A further reduction encounters technological limitations and creates new side effects. Compensation for the "positive" stiffness of the mechanism can be achieved by integrating an element with "negative" stiffness that generates a counteracting force or torque when deflected. In the literature, preloaded tension springs, buckled leaf springs as well as trim masses are predominantly for that purpose. However, most existing approaches are either not monolithic, elaborate to readjust, associated with parasitic forces and torques, or only applicable in a defined orientation relative to the vector of gravity. This paper presents a new concept of monolithic stiffness-compensated mechanisms for use in high-resolution force sensors that is independent of spatial orientation. The negative stiffness is generated by a preloaded spring element of an integrated compensation mechanism. The preload force can be easily adjusted. The compensation force is generated simultaneously with the deflection and transmitted to the main mechanism by a lever and a dedicated coupling element to avoid parasitic effects as much as possible. A suitable design minimizes parasitic motions and avoids buckling of the thin joints as a result of the relatively high preloading force. Finite element simulations are performed to investigate the behavior of the mechanism and to validate the concept.
https://ieeexplore.ieee.org/document/9861932
Photonic reservoir computing with non-linear memory cells: interplay between topology, delay and delayed input. - In: Emerging Topics in Artificial Intelligence (ETAI) 2022, (2022), 1220408, S. 1220408-1-1220408-7
Photonic reservoir computing is an emerging topic due to the possibility to realize very fast devices with minimal training effort. We will discuss the reservoir computing performance of memory cells with a focus on the impact of delay lines and the interplay between coupling topology and performance for various benchmark tasks. We will further show that additional delayed input can be beneficial for reservoir computing setups in general, as it provides an easy tuning parameter, which can improve the performance of a reservoir on a range of tasks.
https://doi.org/10.1117/12.2633339
Wide field of view stereoscopic PIV measurements in a Rayleigh-Bénard cell. - In: Experimentelle Strömungsmechanik - 29. Fachtagung, 6.-8. September 2022, Ilmenau, (2022), 44
Entwicklung eines magnetohydrodynamischen Pumpsystems für die Mikrofluidik. - In: Experimentelle Strömungsmechanik - 29. Fachtagung, 6.-8. September 2022, Ilmenau, (2022), 38
Recent progress on fibre optic shape sensing for aerodynamic applications. - In: Experimentelle Strömungsmechanik - 29. Fachtagung, 6.-8. September 2022, Ilmenau, (2022), 21
Kombinierte Geschwindigkeits- und Temperaturmessungen mittels LED und einer Doppelbildkamera. - In: Experimentelle Strömungsmechanik - 29. Fachtagung, 6.-8. September 2022, Ilmenau, (2022), 3
Development of torque vectoring controller tuned with neural networks. - In: Advances in dynamics of vehicles on roads and tracks II, (2022), S. 1175-1182
The paper introduces an adaptive Torque Vectoring (TV) controller for all-wheel-drive electric vehicles. The main focus of this study lies in tuning procedures of controller gains in accordance with the manoeuvre conditions. For this purpose, a pre-trained neural network predicts the vehicle behaviour and adjusts the PID gains of the TV controller. The proposed method extends the applicability of the TV system and increases its efficiency as compared to the non-adaptive baseline control methods.
Effect of contact pressure on porcine postmortem brain tissue impedance. - In: Proceedings of International Workshop on Impedance Spectroscopy, IWIS 2022, (2022), S. 36-40
In this experimental study we demonstrate the influence of contact pressure on porcine postmortem brain tissue impedance using a movable electrode array and a load cell. We show that the variation of the contact pressure between the tissue and the measurement probe leads to a coefficient of variation in the measured impedance of under 3%. Its influence can therefore be neglected in the investigated use case. Further, we fit the measured impedances to an equivalent circuit model and compare the resistance of grey and white matter brain tissue based on the model parameters.
https://doi.org/10.1109/IWIS57888.2022.9975122