Characterization and alignment of the flexure mechanism for the new Kibble balance at NIST. - In: ASPE Annual Meeting 2022, (2023), S. 80-84
Design of the mechanical system for the quantum electro-mechanical metrology suite. - In: 36th ASPE Annual Meeting 2021, (2022), S. 53-56
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
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
Energy storage for powering fine adjustment systems in hermetically sealed ultra-precision devices. - In: EASS, (2022), insges. 3 S.
Ultra-precision devices are often operated in hermetically sealed chambers to avoid external disturbances and maximize their performance. The remaining disturbing effects are mitigated through compensation or corrective methods. Compensation is frequently done in form of in-situ fine mechanical adjustments of highly sensitive units. Such adjustment systems utilize electromechanical drives to transform electrical energy into an intended motion. Electric cables are used as energy and signal carriers from an external control unit. The associated disturbing effects limit the adjustability. In particular, cable connections act as mechanical coupling elements, introducing indeterminate and time-varying forces. This paper deals with the conceptual design of a fine adjustment system for ultra-precision devices with an integrated energy storage. A spring-based mechanical energy storage system controlled by an optical signal is found to be the most suitable solution for the targeted field of application. The integration of an energy storage in the adjustment system to avoid electric cables and their disturbance effects will significantly improve the quality and stability of the adjustment and further increase the performance of precision devices.
Development of a high precision balance for measuring quantity of dispensed fluid as a new calibration reference for the becquerel. - In: Proceedings of the 22nd International Conference of the European Society for Precision Engineering and Nanotechnology, (2022), S. 337-340
First prototype of a positioning device with subatomic resolution. - In: Proceedings of the 22nd International Conference of the European Society for Precision Engineering and Nanotechnology, (2022), S. 97-100
In the forthgoing work on a device that enables subatomic resolved highly reproducible positioning, a first prototype is here presented. The entire positioning system including the actuator, sensor and guiding mechanism, is realized as a micro-electro-mechanical system (MEMS) on chip level, based on silicon-on-insulator (SOI) technology. A modular printed circuit board acts as the mechanical as well as the electrical contacting interface for the silicon chip. First variants of a linear positioning system comprising axisymmetric double parallel crank structure are investigated. Pivot joints as flexure hinges with concentrated compliance are deployed. These hinges show minimal rotational axis displacement for small angles of deflection, thus ensuring smallest deviations to a straight-line path of the linear guiding mechanism. An electrostatic comb actuator transmits forces contactless to minimize over constraints. A measuring bridge in differential mode utilizes the same comb structures to measure the table position based on the capacitance change. Estimating the position resolution, limited by the resolution of the capacitive sensor, a measurable step width below 50 pm can be expected. In further steps, the device will be a platform to be equipped with a lattice-scale-based position measurement system according to achieve an even higher resolution and reproducibility.
Model-based determination of the reproducibility of kinematic couplings. - In: Proceedings of the 22nd International Conference of the European Society for Precision Engineering and Nanotechnology, (2022), S. 87-90
Investigations on a torque-compensating adjustment drive for mechanically sensitive devices. - In: Proceedings of the 22nd International Conference of the European Society for Precision Engineering and Nanotechnology, (2022), S. 81-82
Adjustable stiffness compensation for monolithic high-precision mechanisms. - In: Proceedings of the 22nd International Conference of the European Society for Precision Engineering and Nanotechnology, (2022), S. 67-68