Atalante – Active piezoelectric bearing with rotating actuators

• Applicant: Professor Dr.-Ing. Stephan Rinderknecht
• Subject Area: Automation, Mechatronics, Control Systems, Intelligent Technical Systems, Robotics ; Engineering Design, Machine Elements, Product Development
• Term: since 2022
• Project identifier: Deutsche Forschungsgemeinschaft (DFG) - Project number 516722405

Rotating machines form the backbone of the technical world. They can be found in almost all areas such as pumps, jet engines and electric motors. However, rotating components are always subject to unbalance which causes a harmonic force excitation during operation and can thereby cause noise and damage. To counteract this, rotors are balanced by adding or removing mass. If the achievable balancing quality is not sufficient or the unbalance changes during operation, active measures can be used for online balancing during operation. The latest active balancing device in this research area is an active bearing with rotating piezo actuators. Its functionality has already been demonstrated in laboratory tests, with a 99% reduction in power consumption compared to conventional piezo bearings. However, unexplained side effects occur in the experiments, such as strong third-order vibrations and static displacements of the rotor during an active operation, which are caused by the three rotating actuators. The research project presented in this proposal investigates the fundamentals of an active bearing with rotating piezo actuators within the load path. The aim of the project is to explain and describe the rotor dynamic effects that occur and to investigate the potential of the bearing for other applications, such as energy harvesting and active vibration control of gearboxes. For this purpose, the active bearing, including non-linear effects such as electrical and mechanical hysteresis, has to be modelled which is accompanied by experiments on a test bench for validation. The model will then be used to simulate the side effects and transfer the insights to an active bearing with more actuators and different used piezo material. The prototype will be first used for active balancing. A model-free control has to be implemented and validated for this task. Furthermore, it will be investigated how much energy can be generated from the deformation of the actuators caused by constant loads, for example due to the gravitational force, and which dynamic side effects occur during the process. In addition, a semi-active control by means of charge inversion will be investigated in order to generate alternating forces, which can potentially be used for active vibration reduction. Finally, all results will be gathered in order to analyse and evaluate the potential of an active bearing with rotating piezo actuators in terms of active balancing, active vibration reduction, health monitoring and energy harvesting.

• DFG Programme: Research Grants