from the rock-and-roll dept.
The coffee, a thermally agitated fluid contained in a cup, has internal degrees of freedom that interact with the cup which, in turn, interacts with the human carrier.
"While humans possess a natural, or gifted, ability to interact with complex objects, our understanding of those interactions -- especially at a quantitative level, is next to zero," said ASU Professor Ying-Cheng Lai, an Arizona State University electrical engineering professor. "We have no conscious ability to analyze the influences of external factors, like noise or climate, on our interactions."
Yet, understanding these external factors is a fundamental issue in applied fields such as soft robotics.
"For example, in design of smart prosthetics, it is becoming increasingly important to build in natural modes of flexibility that mimic the natural motion of human limbs," said Brent Wallace, a former undergraduate student of Lai's and now a doctoral student in ASU's Ira A. Fulton Schools of Engineering. "Such improvements make the prosthetic feel more comfortable and natural to the user."
According to Lai, it is conceivable that, in the not-too-distant future, robots will be deployed in various applications of complex object handing or control which require the kind of coordination and movement control that humans do quite well.
If a robot is designed to walk with a relatively short stride length, then relatively large variations in the frequency of walking are allowed. However, if a longer stride is desired, then the walking frequency should be selected carefully.
A new paper published in Physical Review Applied, "Synchronous Transition in Complex Object Control," originated with Wallace as part of his senior design project in electrical engineering, supervised by Lai. Wallace has received an NSF Graduate Fellowship and now is a doctoral student in ASU's School of Electrical, Computer and Energy Engineering.
The ASU team's research expands on a ground-breaking, virtual experimental study recently conducted by researchers at Northeastern University, using the coffee-cup-holding paradigm and adding a rolling ball, to examine how humans manipulate a complex object. Participants deliberately rotated the cup in a rhythmic manner with the ability to vary force and frequency to ensure the ball stayed contained.
The Northeastern study showed that the participants tend to select either a low-frequency or a high-frequency strategy -- rhythmic motion of the cup -- to handle a complex object.
A remarkable finding was that when a low-frequency strategy was used, the oscillations exhibit in-phase synchronization, but antiphase synchronization arises when a high-frequency strategy was employed.
Brent Wallace, Ling-Wei Kong, Armando Rodriguez, et al. Synchronous Transition in Complex Object Control, Physical Review Applied (DOI: 10.1103/PhysRevApplied.16.034012)