Walking with coffee is a little-known feat of physics

Drinking coffee while walking is something that most of us do every day, but we don't think about how it needs to be balanced

Coffee is a kind of hot stirred liquid in the cup.

Lai Yingcheng, a professor of electrical engineering at Arizona State University, said: "Although humans are born with the ability to interact with complex objects, our understanding of these interactions-especially at the quantitative level, is almost zero

However, understanding these external factors is a basic problem in application fields such as software robots

"For example, in the design of smart prostheses, it is becoming more and more important to imitate the natural movement of human limbs and build with natural flexibility modes," said Brent Wallace, who used to be Lai Is an undergraduate student in Ira a.

According to Lai, it is conceivable that in the not-too-distant future, robots will be deployed in complex object manipulation or control applications that require coordination and motion control that humans are good at

If a robot is designed to walk with a relatively short stride, the change in walking frequency will be relatively large

A new paper published in "Physics Review Applications", "Synchronous Transition of Complex Object Control", was initiated by Wallace as part of his advanced design project in electrical engineering, directed by Lai

The Arizona State University team’s research extends a groundbreaking virtual experimental study, which was recently conducted by researchers at Northeastern University, using the paradigm of holding a coffee cup and adding a rolling ball to test how humans manipulate complex Objects

Research from Northeastern University shows that participants tend to choose low-frequency or high-frequency strategies—the rhythmic movement of the cup—to handle complex objects

A noteworthy finding is that when the low-frequency strategy is used, the oscillations appear as in-phase synchronization, and when the high-frequency strategy is used, the oscillations appear in phase synchronization

Wallace said: "Because both low frequency and high frequency are effective, it is conceivable that some participants in the virtual experiment have changed their strategies

Wallace asked: "In-phase synchronization is related to low-frequency synchronization, and anti-phase synchronization is related to high-frequency synchronization, or vice versa

Driven by Wallace’s curiosity, the research team at Arizona State University studied the transition between in-phase and anti-phase synchronization.

The researchers found that in the weak forcing state, as the external drive frequency changes, the transition is abrupt and occurs at the resonance frequency.
This can be fully understood by the linear system control theory
.

In addition, there is a transition zone between in-phase and anti-phase synchronization.
In this zone, the movement of the trolley and the pendulum are not synchronized
.
Bistability was also found in and near the transition zone on the low-frequency side
.

Overall, the research results show that humans can suddenly and effectively switch from one synchronous attractor to another synchronous attractor.
This mechanism can be used to design intelligent robots to adaptively handle complex objects in a changing environment
.

"Humans may be able to skillfully use in-phase strategies and anti-phase strategies, and unknowingly switch from one strategy to another smoothly
.
The results of this research can be used to apply these human skills to other fields.
Of soft robots, such as rehabilitation and brain-computer interfaces," Lai said
.

In addition, state-of-the-art machines still cannot perform trivial tasks such as running wires on a car body on an assembly line-humans can easily complete these tasks
.

Wallace said: "The systematic quantitative understanding of how humans dynamically interact with the environment will forever change the way we design the world, and may completely change the design of smart prostheses, opening a new era of manufacturing and automation
.
" "By imitating humans We will be able to automate processes that were previously considered impossible with dynamic beneficial behavior when dealing with complex objects
.
"

DOI

10.
1103 / PhysRevApplied.
16.
034012

Synchronous Transition in Complex Object Control