Parametric resonance as an electromechanical transduction mechanism This interdisciplinary research project will explore and exploit parametric excitation, a concept familiar to many as swings in playgrounds are driven by the rider bending and straightening to increase the amplitude of motion. When certain parameters of electrical circuits are modulated at a specific frequency by a mechanical input, such as changing the distance between two metal plates of a capacitor, energy can be transferred efficiently from mechanical to electrical domain. Using ultrasound as the mechanical drive at frequencies that are typically used for medical imaging deep in the body, and with proper design of an electrical circuit, parametric resonance is expected to result in high efficiency wireless charging of medical implants. The same concept can be used to harvest energy from vibrations in the environment in a large frequency range as well as to detect minute acoustic signals for underwater SONAR type applications. This project will thoroughly and systematically investigate the potential of this novel approach and will lead to demonstrative high-performance ultrasound based charging devices and sensors. In terms STEM education, experiments will be designed to instrument riders of swings with motion sensors to illustrate the parametric resonance concept as well as to demonstrate wireless charging of devices with ultrasound in water tanks to high school students. Video clips on experimental results of the project will also be prepared and broadcast through Georgia Tech's public video channel.
The objective of the project will be achieved by a) analyzing parametric resonances of coupled mechanical and electrical resonators, including noise in the analysis for sensing applications while evaluating novel approaches such as piezoelectric resonator based inductor implementation, b) designing and implementing proof-of-concept devices to demonstrate broadband energy harvesting from low frequency vibrations, and low noise acoustic, vibration sensors based on the modeling framework and design guidelines developed, and c) fabricating and carefully characterizing wireless ultrasonic power transfer devices for biomedical implants in the 0.5-2MHz range using MEMS fabrication techniques. The complementary expertise of the research team in analytical modeling of nonlinear complex systems with deterministic and random excitations, device design, fabrication and characterization for applications covering low frequency vibrations for energy harvesting to medical ultrasound applications in the MHz range will be leveraged to achieve the targeted outcomes. The project will formulate new analytical and numerical models and will develop a new experimental framework for designing next-generation electromechanical sensors exploiting nonlinearity and resonance in different ways which can lead to a paradigm shift in transduction which heretofore depended predominantly on linear, passive properties of capacitive and piezoelectric devices.
This award reflects NSF's statutory mission and has been deemed worthy of support through evaluation using the Foundation's intellectual merit and broader impacts review criteria.
