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Mini aircraft navigation sensors could give athletes new data


LabLog – ME Professor 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, Perkins 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.

The above story is reprinted (with editorial adaptations by the U-M Mechanical Engineering Department) from materials provided by the Michigan Engineering LabLog. Read the original story at LabLog.

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