Media-free and non-contact multi-coordinate positioning system using ultrasonic levitation and magnetic guides

• Applicants: Professor Dr.-Ing. Berend Denkena; Professor Dr.-Ing. Jörg Wallaschek
• Subject Area: Metal-Cutting and Abrasive Manufacturing Engineering
• Term: since 2021
• Project identifier: Deutsche Forschungsgemeinschaft (DFG) - Project number 456453238

In the previous DFG project investigated the suitability of the technology combination of ultrasonic levitation and magnetic guidance for use as a guiding system in tool machines. The relatively high stiffness of the guide achieved with this technology combination is of particular interest for precision manufacturing. In addition, the technologies mentioned above allow active intervention in the form of positioning movements, for example for path correction in the micrometer range and for active structural and process damping. In addition, the guide works without any contact and media. Adaptive machine structures based on these technologies have considerable potential for increasing the performance of precision machines. The already researched ultrasonic levitation actuators (ULA) are, among other things, strongly limited in terms of positioning accuracy by thermally induced expansion of the actuators. The overall objective of the project therefore is the research of methods for temperature compensation and load increase in order to enable the successful application of this technology combination in cutting machine tools for precision machining. Both technologies allow active intervention in the form of positioning movements, for example for path correction in the micrometer range, as well as for active structural and process damping with the aim of increasing productivity. In addition, the technology combination works without a wrap-around and media-free. Adaptive machine structures based on these technologies have considerable potential for increasing the performance of precision machines.To achieve this objective, a model for the design of novel ULA is being developed. The model serves to describe the interaction between actuator concept, control strategy, time variance and thermal influences on the dynamic system behavior of the ULA. In addition to the increase in load-bearing capacity, the reduction of the power dissipation of the ULA and its thermal expansion is decisive for the actuator design.A trial carrier assembly for a six-dof micropositioning system is constructed and put into operation with the novel ULA. The experimental setup is used to compare and evaluate different actuator concepts and to test new control strategies. The magnetic actuators as well as the ULA are used as final control element, among other things to influence the compliance of the bearings and to dampen unavoidable system oscillations. For energy-efficient and robust control of the ULA, the developed control strategies are implemented in a new, fast hardware.

• DFG Programme: Research Grants