Session: MNS-02-02 Dynamics of M/NEMS

Paper Number: 74804

Start Time: August 18, 03:20 PM

74804 - Elegant Mems Electrostatic Actuators and Triboelectric Transducers to Enable High Performance Sensors 

The number of wireless devices is predicted to be more than three times humans by 2023 according to Cisco. This growth demands innovative microelectromechanical systems (MEMS) sensors and actuators, which enable new possibilities and functionalities in micro-scale. One of the most common methods of sensing and actuation in MEMS is the electrostatic (capacitive) mechanism consisting of two parallel-plate electrodes, which suffer from limited motion and instabilities.  Designers can open us the design space to consider alternative electrode arrangements that can overcome instabilities and achieve desired performances. We have investigated the electrostatic levitation as a superior actuation mechanism that allows large stroke, large signal-to-noise ratio and pull-in (instability) free capabilities. The levitation configuration consists of two symmetrical side electrodes surrounding the parallel-plate electrodes. This arrangement enables downward and upward forces that creates motion towards and away from the substrate that was not possible with traditional parallel-plate devices. We have created large-stroke accelerometers, microphones and filters that allowed linearity and tunability by combining levitation and parallel-plate electrodes.  This merger led to creation of switches that are initially pulled-in and can open from the voltage applied on the side electrodes, making them more resilient to mechanical shock and wear. The alternative electrode arrangement can be connected to other transducers such as triboelectric mechanisms that convert mechanical motion to electricity. Triboelectric generators have attracted many researchers in the field of energy harvesting, but they suffer from high voltage, small current, and high impedance making the power extraction cumbersome. But the high voltage produced by the triboelectric generators is an excellent source for our levitation actuators that require high voltage to operate. Connecting the triboelectric transducers to levitation switches, we presented a self-powered switch sensor that operates from mechanical shock and opens from an initially pulled-in position. The proposed system can be used to create an alarm when the mechanical shock exceeds certain limit. The synergy between the two transducers creates an autonomous system that unlike the traditional shock sensing systems does not require signal processing, therefore it simplifies the system significantly. The invited talk provides a perspective on novel combination of these transducers to overcome the limitation of traditional designs and discover high performance micro-actuators and sensors.

Presenting Author: Shahrzad (Sherry) Towfighian Binghamton Univ

Authors:

Shahrzad (Sherry) Towfighian Binghamton Univ