Eventos Anais de eventos
COBEM 2017
24th ABCM International Congress of Mechanical Engineering
Robust design and uncertainty analysis of an energy harvesting resonant device
Submission Author:
Paulo Martins , SP
Co-Authors:
Marcelo A. Trindade, Paulo Martins
Presenter: Paulo Martins
doi://10.26678/ABCM.COBEM2017.COB17-0881
Abstract
The use of electrical energy increases continuously and very rapidly and, thus, the search for alternative energy sources attracts important research effort. Recently, several studies were directed to energy harvesting from ambient sources, such as mechanical vibrations from machines and structures. One popular energy harvesting device consists on a cantilever beam with tip mass, designed to resonate at the operating frequency of the machine to which it is attached. The beam bending vibration is then converted into electrical energy through a bonded piezoelectric material that should be connected to a proper harvesting circuit. To ensure greater amounts of harvested energy, it is important to optimize the harvesting device as well as properly tune resonance and operating frequencies. Besides, even optimized devices performance may be affected by uncertainties and variabilities due to environmental changes and/or manufacturing tolerances. Therefore, robust design techniques may be required in order to reduce device's performance sensitivity to expected uncertainties. There exists some well-known robust design optimization techniques, but there is not much research applying them to dynamics and vibrations since it may be computationally expensive. This work aims at applying a less expensive robust design technique, known as Taguchi method, to design a piezoelectric energy harvesting device when subjected to uncertainties in harvesting circuit impedance, device-machine attachment effectiveness, and overall damping. This is done using an electromechanical coupled finite element model for the cantilever beam with tip mass and base excitation. Deterministic Sequential Quadratic Programming optimization is performed to guarantee proper tuning of nominal harvesting devices. Then, using Taguchi method, a search for devices and circuit impedance that provide satisfactory trade-off between nominal performance and robustness is performed. Results show that with little deviation from nominal designs, robustness can be increased without much loss in mean performance.
Keywords
energy harvesting, Uncertainties, Vibration, robust design, Piezoelectric materials
