When a self-driving car or drone loses GPS contact, it uses inertial measurement units (IMus) to track its position in space,media reported. Now, thanks to a newly developed mini-gyroscope, such a device may soon be more accurate than ever.
Typically, IMU consists of multiple gyroscopes, accelerometers, and magnetometers. However, the performance of the gyroscope is limited because it is not very precise — more accurate gyroscopes do exist, but they are often too expensive to integrate effectively into the IMU.
Led by Professor Khalil Najafi, scientists at the University of Michigan set out to solve the problem. The micro-gyro is reported to be 10,000 times more accurate than the gyroscope used in smartphones today, but it costs “only” 10 times that of the latter – it is said to cost only one-thousandth of the size of the larger gyroscope available.
At the heart of the device is a one-centimeter-wide metal-coated glass resonator, which looks like an upside-down cake pot. It is made of pure fused quartz, about 1/4 inch thick, with a bottom edge surrounded by a circle of electrodes. The push and pull on the resonator allow it to vibrate and ring like a wine glass.
The entire unit is encased in a vacuum container about half a centimeter high. This avoids the attenuation of air-to-vibration, which is measured by the electrode that produces the vibration.
“Basically, glass resonators vibrate in some mode,” says Sajal Singh, a PhD student. If you suddenly rotate it, the vibration mode will remain in its original direction. As a result, the speed and angle can be measured directly by monitoring the vibration pattern. “
The technology is currently being commercialized by Enertia Microsystems. It will eventually be used not only in cars, drones and other vehicles, but also for military applications or self-guided warehouse robots.