Nonlinear shaping and adjusting of parametric resonances for enhancing characteristics in resonant microsensors

• Applicant: Professor Dr.-Ing. Thomas Sattel
• Subject Area: Mechanics
• Term: since 2025
• Project identifier: Deutsche Forschungsgemeinschaft (DFG) - Project number 556709080

Microelectromechanical system resonators (MEMS resonators) have now gained considerable importance as sensors in many precision engineering applications, including use in automotive gyroscopes for yaw rate measurement, in gas sensors for detecting minute amounts of gas, in communications technology as constant frequency sources and timers, or for atomic force microscopy. From a vibration engineering viewpoint, these applications share a least two important performance characteristics: sensitivity and settling time. Closely related to the settling time is the measurement speed. Solutions based on linear systems and forced vibrations can however improve only either sensitivity or settling time. The proposed project seeks to investigate open scientific questions to find technologically viable solutions that overcome the trade-off problem between sensitivity and settling time. To achieve this, the proposal work investigates mechanisms and nonlinear concepts of resonant MEMS-sensors to find novel operation modes, which can simultaneously improve both sensitivity and settling time. The suggested approach combines parametric resonances together with shapable and adjustable nonlinearities. Parametric excitation is already known for improved sensitivity measures compared to classical forced excitation. New operation schemes will directly be applied to resonant MEMS-sensors used in dynamic Atomic Force Microscopy. The MEMS sensors are first characterized experimentally and then represented as a beam model with integrated electro-thermomechanical behaviour. Analyses include modal discretization, model simulations and comparison of theoretical findings with experimental results. The main part of the project uses standard methods and procedures from nonlinear dynamic system theory to investigate various parametric resonances and nonlinearities with respect to the projects aim. This includes local and global parametric ranges and performance of steady-state and transient analyses. Considerations include time simulations, stability analyses, Floquet analyses, continuation methods, and basin-of-attraction analysis. Most potentially suitable nonlinearities will be implemented in an experimental setup, with which a systematic and comprehensive system analysis is then conducted. Following the idea of freely shaping and adjusting nonlinearities, a feedback loop between the sensor and actuator of the MEMS-sensors are developed. Due to the demand on short computation time, this will be realised using an FPGA within a control loop. In the final step the achievable improvements of the novel approaches compared to the classical linear operation mode with forced excitation, will be investigated experimentally.

• DFG Programme: Research Grants