MEMS Sensing and Control research lab


MEMS Sensing and Control research lab



Micro-Electro-Mechanical Systems (MEMS) have been gaining a lot of interest in the reacent years due to their cheap manufacturing costs, mass-producability, low weight and power cosumption, and their very high accuracy.

Our lab is set to study Micro-oscillator-type MEMS devices and use their unique features to create new, more reliable sensors.

Micro-oscillators have been used to create high precision mass sensors, gyroscopes and accelerometers (that are very commonly found in cars' airbag deployment system and cellphones). This is because of the unique vibration properties MEMS devices exhibit as a result of their nonlinear vibration.

Our lab is located in PKI 117B. It is equipped with a stat-of-the-art holographic MEMS analyzer to study the static and dynamic respsonse of our MEMS devices. The MEMS analyzer is also equipped with a stroboscope to offer a borad range of oscillation frequencies and input voltage 

The MEMS analyzer, shown in the figure aside, measures the oscillation of a micro-beam, either in a horizontal or a vertical plane. To achieve higher oscillation magnitude, the microbeam is enclosed in a vacuum chamber.

http://engineering.unl.edu/images/uploads/DHM%202.jpg

Current Projects

MEMS Humidity sensor

In this project we propose the use of an electrostatic MEMS (Microelectromechanical system) oscillator exposed to air to measure relative humidity. As water content in air changes, this should change the MEMS air viscosity and its air’s dielectric constant. Because those changes are so small, we propose amplifying the sensor’s response by dynamically driving the sensor at its subharmonic regime (actuation at twice the natural frequency). At this regime, the output of the sensor makes a big jump at a particular input frequency. This frequency is related to the air’s squeeze film damping (which is a function of the air humidity). 

 Our novel idea eliminates the need of the polymer layers typically used in current MEMS humidity sensors. Those layers are known to degrade with time, which limits the sensor’s life span and its accuracy.MEMS Oscillators are found to have a life of the magnitude 10^7 Hours. Moreover, because of their microscale sizes and the use of capacitive sensing, Electrostatic MEMS devices require very little energy to run (in the mW range) and can be powered with a single battery for a very long time. It can also be powered using energy harvesting, which is one of our future projects.