IMU work to aid tracking, navigation and orientation

September 21, 2018

Computers and smart devices are quick, but sometimes dumb.

They can process calculations far faster than the human mind, and complete functions that we can only dream of. But they have struggled in some areas to mimic and supersede the range and complexity of human ability – particularly when it comes to responding to the world around us.

The human mind is adaptable, responsive and intelligent. Our gadgets, not so much.

That presents an opportunity for innovation. The more capable and autonomous we make our technologies, the more they can do for mankind, freeing us up to do other important things.

But that sort of independent function will require better enabling technologies, particularly in the area of navigation, orientation, and tracking by using information from various types of sensors.

In response to this need, Masdar Institute is working with Singapore’s Agency for Science Technology and Research (A*STAR) and the international semiconductor giant GlobalFoundries to use microelectromechanical systems (MEMS) to develop an advanced inertial measurement unit (IMU), which combines multiple types of sensors in a single platform.

An IMU is an electronic device that integrates accelerometers, gyroscopes, and magnetometers to report how fast it’s going, how much gravity is acting on it, and which way it’s pointing.

The accelerometer detects the rate of acceleration, the gyroscope detects changes in the device’s rotational orientation and the magnetometer detects three-dimensional orientation and calibrate against orientation drift.

These mini-devices come together in a single unit to facilitate self-navigating, self-focusing, self-tracking and self-piloting in a number of applications.

Uses so far include the Segway personal transportation system, spaceship navigation and motion capture technology.

Existing IMUs are relatively costly and somewhat limited. Even the best of them has limited bandwidth, sensitivity, signal-to-noise ratio, packaging, etc.

Product designers are crying out for better, smaller, cheaper IMUs that would let them make smaller, cheaper and – crucially – smarter devices.

We are working to leverage Abu Dhabi’s growing MEMS expertise to develop IMUs that are cheaper to produce and able to be integrated into far more types of technologies and industries, like sports, gaming, personal electronics and more. In particular, we are looking to leverage our optomechanical MEMS expertise to build more dynamic IMUs.

Optomechanics involve the interaction of electromagnetic radiation with mechanical systems via radiation pressure. Converting a mechanical signal into and optical one provides a robust platform against electromagnetic interference, while giving a usefully wide dynamic range, and low signal distortion.

These IMUs can transform mechanical motion of an inertial mass into an electric signal.  

Optomechanically-integrated MEMS-based IMUs perform very well at low frequencies, and are usually capped in a special gas environment to make them sensitive, stable, shock-resistant, and good at carrying a signal without too much ‘noise’.

Additionally, MEMS-based gyroscopes are small, not too power-hungry, and relatively cheap to make.

All this isn’t without challenges, though. MEMS-based gyroscopes don’t perform as well as others. We are using our diverse areas of expertise – including cutting edge microsystems, optomechanics and materials science – to address that problem and others to develop a small, accurate, low-power gyroscope.

We are confident that our work towards an IMU-based on micro/opto/nanotechnology will enable a number of power, size and resolution applications for IMU that the current cutting edge cannot meet, providing Abu Dhabi with the intellectual property and expertise for a growing and high value industry.

According to IndustryARC, the market for IMUs is expected to grow from US$2.2 billion in 2013 to US$3.2 billion by 2018. This MEMS-related research will help Abu Dhabi develop its microsystems expertise necessary for its knowledge-economy transformation, and help it become a leader in technological innovation.

Dr. Daniel Choi is an associate professor and head of the department of mechanical and materials engineering at the Masdar Institute of Science and Technology; Dr. Irfan Saadat is professor and Dr. Mahmoud Rasras is associate professor of microsystems engineering. This piece is the fourth in a series covering MEMS research at the Masdar Institute.