Carrying a cup of coffee while walking doesn't seem that hard. People do it every day. But it's actually more complicated than it looks -- the coffee sloshes around and it's hot enough to hurt you if it splashes out. So engineers want to know more about just how we do it. 

Researchers from Arizona State University have published a paper in the science journal Physical Review Applied that delves into coffee-carrying strategies -- and it might help them develop smart robots.

"A complex object is a system with internal degrees of freedom, such as a cup of hot coffee handheld by a human in walking," researchers write. "In spite of the natural ability of humans to handle complex objects, an understanding of how this is accomplished is lacking, yet the issue is fundamental to applied fields such as soft robotics."

Using a moving bowl with a mechanical ball inside instead of a coffee cup, researchers learned that humans use two separate strategies to handle what they call a complex object, like the cup full of coffee. But the research is less about those strategies and more about the transition between the two, how humans instinctively know how to switch methods and not end up splashed with decaf. 

Robots don't have this instinct, duh, but studying how we humans do it can help engineers design smart robots that eventually may need to handle complex objects and shift strategies on the go.

"The findings from this study can be used to implement these human skills into soft robots with applications in other fields, such as rehabilitation and brain-machine interface," study co-author Ying-Cheng Lai said in a statement.

Making smarter robots may still seem like something the Terminator movies tried to warn us against, but innovative robots could actually help keep us healthy.