Nav: Home

Small, precise and affordable gyroscope for navigating without GPS

March 23, 2020

ANN ARBOR--A small, inexpensive and highly accurate gyroscope, developed at the University of Michigan, could help drones and autonomous cars stay on track without a GPS signal.

"Our gyroscope is 10,000 times more accurate but only 10 times more expensive than gyroscopes used in your typical cell phones. This gyroscope is 1,000 times less expensive than much larger gyroscopes with similar performance," said Khalil Najafi, the Schlumberger Professor of Engineering at U-M and a professor of electrical engineering and computer science.

Most smartphones contain gyroscopes to detect the orientation of the screen and help figure out which way we're facing, but their accuracy is poor. They're the reason why phones often incorrectly indicate which direction a user is facing during navigation.

It doesn't matter much to a human on the street or behind the wheel, but a driverless car could get lost quickly with a loss of GPS signal. Inside their backup navigation systems, autonomous vehicles currently use high-performance gyroscopes that are larger and much more expensive.

"High-performance gyroscopes are a bottleneck, and they have been for a long time. This gyroscope can remove this bottleneck by enabling the use of high-precision and low-cost inertial navigation in most autonomous vehicles," said Jae Yoong Cho, an assistant research scientist in electrical engineering and computer science.

Better backup navigation equipment could also help soldiers find their way in areas where GPS signals have been jammed. Or in a more mundane scenario, accurate indoor navigation could speed up warehouse robots.

The device that enables navigation without a consistent orienting signal is called an inertial measurement unit. It is made up of three accelerometers and three gyroscopes, one for each axis in space. But getting a good read on which way you're going with existing IMUs is so pricey that it has been out of range, even for equipment as expensive as autonomous vehicles.

The key to making this affordable, small gyroscope is a nearly symmetrical mechanical resonator. It looks like a Bundt pan crossed with a wine glass, made one centimeter wide. As with wine glasses, the duration of the ringing tone produced when the glass is struck depends on the quality of the glass--but instead of being an aesthetic feature, the ring is crucial to the gyroscope's function. The complete device uses electrodes placed around the glass resonator to push and pull on the glass, making it ring and keeping it going.

"Basically, the glass resonator vibrates in a certain pattern. If you suddenly rotate it, the vibrating pattern wants to stay in its original orientation. So, by monitoring the vibration pattern it is possible to directly measure rotation rate and angle," said Sajal Singh, a doctoral student in electrical and computer engineering who helped develop the manufacturing process.

The way that the vibrating motion moves through the glass reveals when, how fast and by how much the gyroscope spins in space.

To make their resonators as perfect as possible, Najafi's team starts with a nearly perfect sheet of pure glass, known as fused-silica, about a quarter of a millimeter thick. They use a blowtorch to heat the glass and then mold it into a Bundt-like shape--known as a "birdbath" resonator since it also resembles an upside-down birdbath.

Then, they add a metallic coating to the shell and place electrodes around it that initiate and measure vibrations in the glass. The whole thing is encased in a vacuum package, about the footprint of a postage stamp and half a centimeter tall, which prevents air from quickly damping out the vibrations.
-end-
The paper, "0.00016 deg/?hr angle random walk (ARW) and 0.0014 deg/hr bias instability (BI) from a 5.2M-Q and 1-cm precision shell integrating (PSI) gyroscope," is scheduled to be presented at the (now virtual) 7th IEEE international Symposium on Inertial Sensors & Systems March 25.

Image: https://docs.google.com/document/d/1oH_iFeZ78PbcUlQy07AUREyCYn1Cnekaq7BoTYP2paM/edit

The research was supported by the Defense Advanced Research Projects Agency.

Cho and Najafi are co-founders of a startup company, Enertia Microsystems, based on the technology licensed from U-M.

The process for making the gyroscope was developed in the Lurie Nanofabrication Facility.

Khalil Najafi

University of Michigan

Related Engineering Articles:

Re-engineering antibodies for COVID-19
Catholic University of America researcher uses 'in silico' analysis to fast-track passive immunity
Next frontier in bacterial engineering
A new technique overcomes a serious hurdle in the field of bacterial design and engineering.
COVID-19 and the role of tissue engineering
Tissue engineering has a unique set of tools and technologies for developing preventive strategies, diagnostics, and treatments that can play an important role during the ongoing COVID-19 pandemic.
Engineering the meniscus
Damage to the meniscus is common, but there remains an unmet need for improved restorative therapies that can overcome poor healing in the avascular regions.
Artificially engineering the intestine
Short bowel syndrome is a debilitating condition with few treatment options, and these treatments have limited efficacy.
Reverse engineering the fireworks of life
An interdisciplinary team of Princeton researchers has successfully reverse engineered the components and sequence of events that lead to microtubule branching.
New method for engineering metabolic pathways
Two approaches provide a faster way to create enzymes and analyze their reactions, leading to the design of more complex molecules.
Engineering for high-speed devices
A research team from the University of Delaware has developed cutting-edge technology for photonics devices that could enable faster communications between phones and computers.
Breakthrough in blood vessel engineering
Growing functional blood vessel networks is no easy task. Previously, other groups have made networks that span millimeters in size.
Next-gen batteries possible with new engineering approach
Dramatically longer-lasting, faster-charging and safer lithium metal batteries may be possible, according to Penn State research, recently published in Nature Energy.
More Engineering News and Engineering Current Events

Trending Science News

Current Coronavirus (COVID-19) News

Top Science Podcasts

We have hand picked the top science podcasts of 2020.
Now Playing: TED Radio Hour

Listen Again: The Power Of Spaces
How do spaces shape the human experience? In what ways do our rooms, homes, and buildings give us meaning and purpose? This hour, TED speakers explore the power of the spaces we make and inhabit. Guests include architect Michael Murphy, musician David Byrne, artist Es Devlin, and architect Siamak Hariri.
Now Playing: Science for the People

#576 Science Communication in Creative Places
When you think of science communication, you might think of TED talks or museum talks or video talks, or... people giving lectures. It's a lot of people talking. But there's more to sci comm than that. This week host Bethany Brookshire talks to three people who have looked at science communication in places you might not expect it. We'll speak with Mauna Dasari, a graduate student at Notre Dame, about making mammals into a March Madness match. We'll talk with Sarah Garner, director of the Pathologists Assistant Program at Tulane University School of Medicine, who takes pathology instruction out of...
Now Playing: Radiolab

What If?
There's plenty of speculation about what Donald Trump might do in the wake of the election. Would he dispute the results if he loses? Would he simply refuse to leave office, or even try to use the military to maintain control? Last summer, Rosa Brooks got together a team of experts and political operatives from both sides of the aisle to ask a slightly different question. Rather than arguing about whether he'd do those things, they dug into what exactly would happen if he did. Part war game part choose your own adventure, Rosa's Transition Integrity Project doesn't give us any predictions, and it isn't a referendum on Trump. Instead, it's a deeply illuminating stress test on our laws, our institutions, and on the commitment to democracy written into the constitution. This episode was reported by Bethel Habte, with help from Tracie Hunte, and produced by Bethel Habte. Jeremy Bloom provided original music. Support Radiolab by becoming a member today at Radiolab.org/donate.     You can read The Transition Integrity Project's report here.