Tuesday, December 7, 2010

Mini aircraft navigation sensors could give athletes new data

A technology developed for fly fishing is expanding to baseball and other sports.

Noel Perkins was a novice fly fisherman frustrated that he couldn't perfect his cast. He talked with experts. He hired instructors. He practiced. And when nothing worked well enough, rather than hang up his fishing rod, the mechanical engineering professor scaled down some spacecraft navigation sensors and installed them on his equipment.

Finally, armed with graphs from his mini angular rate gyros, Perkins was able to make real progress.

His widget, the Fly Casting Analyzer, could measure and chart the motion of his fly rod through the air. It could show him exactly what he was doing as he cast it, and, perhaps more importantly, why the experts were doing better. It allowed him to, for example, quantify what instructors meant when they told him his cast wasn't "smooth" enough. He could tell what portion of his stroke was causing his problems, and when he should be holding the fly rod still. 

Almost a decade later, the technology has gotten smaller and more sophisticated. Now it incorporates mini accelerometers, another type of sensor used in aircraft.

With two patents and licensing agreements with a cadre of companies, Perkins and his students are working to adapt and commercialize the technology for golf, bowling, basketball, softball and baseball, among other possible applications. It’s designed to give athletes and coaches new information that other instruments and high speed cameras can't provide: It immediately quantifies linear and angular motion about three axes, the professor says.

Perkins and grad students Ryan McGinnis and Stephen Cain tested the baseball version of the device a few weeks ago with a net and a tee in the shadow of the Walgreen Drama Center. They were able to, in a sense, zoom in on the underlying physics of their swings.

The device clocked McGinnis’s grip speed at 15 mph, and his barrel speed at 75 mph---about five times greater. While it's known that grip speed and bat rotational speed combine to produce the bat's barrel speed, Perkins says no one's ever been able to quantify or measure it. Now, he knows exactly how important the rotational speed is in transferring speed (and power) from the grip to the barrel. Watch more swing videos with graphs.

Monday, November 29, 2010

Meet Stephen ColBot: Special communications relay robot

New video footage from the MAGIC robotics competition in Australia has revealed the winning University of Michigan team's secret weapon.

Stephen ColBot served as the "special communications relay" robot, which essentially told all the other robots what to do as they navigated and mapped the brutal Brisbane terrain, neutralizing mock bombs, explains team adviser Edwin Olson.

The U-M team is now back from Brisbane, where they took the $750,000 first prize out of more than 20 teams in the international competition sponsored by the U.S. Department of Defense and its Australian counterpart. The goal of the contest was to produce new smart, unmanned technologies that could one day be used in urban combat zones. Read more about the contest.

Thursday, November 4, 2010

Gamma-ray vision could improve nuclear materials detection

Special nuclear materials---the plutonium and uranium that are the main ingredients in nuclear weapons---aren't easy to detect and then find. But a new tool created by engineering professor Zhong He could give an inspector gamma-ray vision, allowing him to see the precise location of any dangerous nuclear materials.

Gamma rays are high energy photons that special nuclear materials emit. The gamma ray detectors used today can only tell you that there's more radiation in a particular area. They can't tell you where it's coming from.

He's new detector, called Polaris, is the first to give a real-time image of gamma ray emissions, so it could lead an inspector directly to any special nuclear materials giving off high concentrations. The research has received millions in government funding. It's being tested right now by the Department of Defense.

Polaris has, for the first time, allowed humans to actually see the Earth's natural background radiation, He says: "We can see radiation from building concrete wall, which is higher intensity than gamma rays emitted in the air, for example."

Another nice thing about it is that it works at room temperature. Today's typical gamma ray detectors have to be cooled to a frosty -200 degrees Celsius to work. That makes them kind of cumbersome to use in the field.

He is a professor in the University of Michigan Department of Nuclear Engineering and Radiological Sciences. He is working on this technology with Ph.D. students Chris Wahl and Weiyi Wang. Here's the whole press release.

Tuesday, October 12, 2010

Architecture research in the virtual reality cave

Architecture associate professor Moji Navvab, who helped plan the Big House renovation so that more noise stays inside the stadium, is doing some interesting work in the North Campus virtual reality cave.

Navvab studies sound and light and how it reaches the eyes and ears under different conditions. In the cave, he's trying to answer questions such as: Why does an interior designer favor one wall color over another? How does blue-tinged LED light affect the eyes of someone reading under it? How would a painting created in natural light look in a gallery at night?

He is quantifying color preferences and measuring how color affects pupil size. In this video, he explains the work and gives a tour of his dummy-head sensor complete with replicas of a human ear.

Wednesday, September 15, 2010

Human joysticks and autonomous quadcopters

Aerospace engineering sophomore Duncan Miller spent his summer playing with mini quadcopters (helicopters with four rotors) at NASA Langley Research Center. In this video, he demonstrates the "sense-and-avoid" programming he and his fellow interns wrote and tested. That's Miller with the helmet on.

"In the video," Miller says, "I am acting like a human joystick. The quadrotor is matching my helmet's orientation and altitude. When I look left, the quadrotor yaws to the left. When I look to the right, it follows suit. If I get on my knees, it will lower itself to my eye level again."

How does it do this? Tracking cameras around the room have been programmed to recognize certain reflector dots as objects. In the first part of the video, the students had placed the reflector dots on another quadcopter. In the second part, they're on the helmet. The cameras send a signal to a computer, which sends a signal to the quadcopter about what it needs to avoid.

This was actually quite serious work. In addition to his stint in the helmet, Miller focused on hardware and loop simulations and testing decision algorithms. He and his colleagues set up a functioning autonomous vehicle laboratory. Researchers can now use it to study things like swarming autonomous vehicles and aircraft sense-and-avoid issues, says NASA systems engineer Garry Qualls.

The quadcopters the students used are prototype models of the Parrot AR.Drone "flying video game" that hit the market in early September. (The drones don't come with this autonomous mode, though.)

Wednesday, September 1, 2010

Chasing dust storms and measuring their electrical charges

Understanding how bouncing grains of sand and dust become electrified has applications in climate prediction, electronics manufacturing and Mars exploration.

"You can see clouds forming on the updraft from several miles away and as the gust front moves closer, the world seems to shrink. The horizon gets a little fuzzy. The light dims. And the whole sky turns a very dramatic red.

"In the midst of it, it's essentially a blizzard, except getting sandblasted hurts a whole lot more. Your eyes burn. It's hard to breathe. And you can barely stand against the wind. It's dark enough that if you're driving you'll need to turn your headlights on. After 15 or 20 minutes, the rain starts and the dust falls out of the sky like the drop of a curtain."
That’s atmospheric science Ph.D. student Harvey Elliott’s description of a Haboob---an intense sand storm that kicks up in arid places like the African Sahel. Elliott spent a month in Niamey, Niger this summer---one of two field trips to study the electrostatics of airborne dust and sand. The other trip was to Boulder City, Nevada, where he studied dust devils, ran into their vortices with a video camera and then spent a day cleaning their remains out of his rented Chevy Malibu.

The video above has some of Elliott's footage, plus some from other students who have worked on this project with Professor Nilton Renno over the past five years.

With his colleagues in 2008, Renno demonstrated that dust and sand grains get electrified as they bounce along a surface. They also developed a unique electric field sensor to measure this. Now Elliott is working with Renno to use this sensor to better understand the phenomenon. The research has practical applications on Earth and on Mars.

Understanding the physics of dust- and sand-lifting could help scientists come up with more precise climate change models, as these aerosol particles and their effects on global warming are still uncertain.

And in the semiconductor and electronics industries, unpredictable electrostatic “shock” discharges (exacerbated by dust and human handling of parts) cause billions of dollars in damage per year, Renno says. Right now, there’s no reliable way to measure electric fields and charged particles in manufacturing plants on an ongoing basis. Renno’s sensor can do this. It would allow mitigating measures to go into action before a shock discharge occurred, preventing damage.

Electrostatics in Martian dust storms could affect our instruments on landers there, and could also have major implications for future human explorers.

The sensor is being commercialized through the U-M spin-out company EngXT. Renno is giving a keynote talk about it Oct. 5, 2010 in Reno, Nevada, at the Electrostatic Discharge Association's Annual Meeting.

Friday, August 13, 2010

Watching concrete crack: A new strength record

A small slab of a special concrete laced with short, twisted wires set a tensile strength record a few weeks ago in the civil engineering Structures Lab, the researchers involved say. Tensile strength is essentially resistance to stretching.

This stuff has about 100 times the stretchiness of conventional concrete. It can withstand 5,000 pounds per square inch after it starts cracking. It's the combination of strength and stretchiness that makes the material unique, the researchers say.

Postdoctoral researcher Kay Wille and professor emeritus Antoine Naaman invited me to watch one of their tests. They put a specimen of their concrete in a machine that pulls it apart until it fractures. I videotaped it. I was expecting something dramatic.

Turns out the drama was in what didn't happen. The material didn't break in half. It slowly cracked in scratches so tiny we could barely see them without a microscope. Wille first knew they were happening because he heard them.

There's more detail in the video. Naaman even offers to test anyone else's plate-like specimen purported to be stronger than theirs. (That buzz in the background is the natural din of the lab.)

Wille and Naaman are working on this new "ultra-high performance fiber reinforced material" with associate professor Gustavo Parra-Montesinos and professor Sherif Al Tawil.

Wednesday, August 4, 2010

A real-world test for a "fishy" clean energy technology

A device that works like a fish to harness clean, renewable energy from slow water currents was recently tested in the St. Clair River. This was the first real-world trial for VIVACE, which stands for Vortex Induced Vibrations for Aquatic Clean Energy. Here's some underwater video courtesy of Vortex Hydro Energy, the University of Michigan spin-out company that's commercializing it.

This is some seriously clever technology. Its shape and placement in the water set off "vortex induced vibration," a phenomenon that fish use to help them swim faster in a school. These are the same vibrations that, in wind, toppled the Tacoma Narrows bridge in 1940. Here's more detail on how it works and why it improves upon other hydrokinetic energy technologies.

On Aug. 2, researchers lowered a 10x11x15-foot, two-cylinder array 16 feet deep and 60 feet from shore at Port Huron. The converters ran for two hours.

“We’re very optimistic because it performed well," said Gus Simiao, CEO of Vortex Hydro Energy. "We did have one glitch with one of the subsystems, but it’s something that we can repair. We just have to spend some time redesigning it and testing it in the lab before we go back to the river.”

The team expects to be back at the river in May or June of 2011, when they plan to leave it there for prolonged testing over a couple of months.

Bernitsas is a professor in the Department of Naval Architecture and Marine Engineering.