When robots touch the world

Penn Engineering’s Michael Posa discusses robotics in the age of artificial intelligence, the ambulatory genius of toddlers, navigating the unfamiliar and the elegance of not learning everything.

Penn Engineering’s Michael Posa is an assistant professor in the Department of Mechanical Engineering and Applied Mechanics and the recipient of an April 2023 grant renewal from the Toyota Research Institute (TRI). His work with TRI untangles the complexities of legged locomotion—refining the still-limited ability of robots to walk and run—and streamlines manipulation, producing simulations that simplify the way robots grasp unknown contexts and objects.

Michael Posa.
Michael Posa, assistant professor in the Department of Mechanical Engineering and Applied Mechanics. (Image: Penn Engineering Today)

Posa outlines why, at this point in robotics development, it is still difficult to get a robot to walk or hold things. “Right now,” he explains, “robots are burdened by a mismatch between the complex computerized instructions we give them and the level of simplicity required to be effective. Humans have an intuition for touching the world that doesn’t mesh with the type of algorithms designed to get robots to do the same.”

“If you were to look at the physics of a problem—say, the dexterous manipulation of an object—and you were trying to simulate it on your computer, you would have some complicated geometries of the object, some complicated geometries of the hand and the interaction between these two geometries. This is where the bulk of computation would be done, and it would be inexact, energy-intensive and time-consuming. But, if you think about how a human might pick up and manipulate an object, that level of complexity seems unnecessary.”

A major difference between the ease of robotic and human motion is that humans don’t need to compute every level of complexity, Posa says. “The human hand is complex, but in practice, it doesn’t often use its full complexity. Humans have found a way of simplifying the problem of planning, control and manipulation that we haven’t found the right equivalent for in computation. Same for walking. Toddlers have intuitive understanding of getting around and balancing that outstrips what most robots can achieve.”

Why, then, is it important for engineers to develop robots that can touch the world the way humans do? Because, Posa explains, “some tasks are naturally suited to robots. It really comes down to work that is unsafe or undesirable for humans to do. In robotics, we talk about the three Ds: dirty, dangerous, and dull. These are tasks that humans do with some risk that robots could alleviate, but it’s important to also realize that robots can do more than just take over the dirty work, they can also provide and enhance a social function.”

This story is by Devorah Fischler. Read more at Penn Engineering Today.