Recently, there has been an increased demand in innovative power generation solutions for electronics with low-energy consumption. Portable and miniature equipment attracts wide attention due to its potential in wireless and remote sensing, mobile electronics, wearable health devices, independent assistive technology, space, and military applications. Energy harvesters can harness wasted mechanical and thermal energies and use it to operate various modern electronic devices when conventional power sources are unavailable or impractical. The wasted energy can be due to a vibratory motion, heat flux, difference of temperature, etc.  Common energy harvesting techniques employ piezoelectric, electromagnetic, triboelectric, photovoltaic, thermoelectric, and electrostatic conversion principles depending on the application .Consequently, the development of microelectromechanical (MEMS) and nanoelectromechanical (NEMS) systems has allowed for the integration of mechanical and electronic systems which enhance the capabilities of so many devices we interact with every day, such as cellphones, pacemakers, drug delivery systems and inertial sensors.

Past inadequacies in modeling of gyroscope inertial sensor systems have presented issues of reliability for micro- and nano-scale gyroscopes. In this work, a homogenization approach is considered for a multiphase micromechanical model of an electrostatically actuated gyroscope, consisting of a partially-covered piezoelectric cantilever beam with fixed tip mass, and developed to determine the effective material properties for the different material structure architecture. In order to design efficient MEMS/NEMS gyroscopes, size dependent coupled stress and surface elasticity effects are incorporated into a classical Euler-Bernoulli beam model to investigate their influences. When designing and manufacturing energy harvesters at the nano-scale, the size dependency effects including the nonlocal effects, surface elasticity, and surface integrity of the structure have to be implemented in order to accurately model the continuum mechanics characteristics of the system. Then, the Differential Quadrature Method will be employed in order to discretize the governing nonlinear equations of motion and associated boundary conditions. The model is then used to investigate how size dependent effects influence the static pull-in instability, the natural frequencies, and the performance of the gyroscope when the size is decreased from micro to nano scale. In this study, a focus is also paid on using piezoelectric materials and their usefulness from energy harvesting point of view. This includes integrating a piezoelectric patch in place of a sensing electrode in the gyroscope system. Doing this will allow for the piezoelectric patch to perform two tasks simultaneously, sensing changes in angular velocity for guidance and harvesting energy through the piezoelectric effect, thus removing the requirement to replace batteries or running wires to charge the device.

 


Novel Design of Piezoelectric Sensing and Energy Harvesting Mems/nems Gyroscopes

Division / Sponsors: 
Design Engineering Division and Computers & Information In Engineering Division


Paper Proceedings: https://asmedigitalcollection.asme.org/IDETC-CIE/IDETC-CIE2020/volume/83907

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