Robot Hands Evolving To Copy Human Hands

If anybody wants to guess the purpose of any given futuristic humanoid robot, they only need to look at its hands. Last week, a pair of videos released by Boston Dynamics and Figure AI provided clear examples that certain tasks simply require much more "human touch."

In the first case, Hyundai-owned Boston Dynamics showed off a new pair of "grippers" for its trimmed-down Atlas factory robot. (Readers familiar with the company may be more familiar with Atlas' older, beefier predecessor).

The claw-like, three-digit pincer features three fingers, one functioning as an extra-long thumb, a combination particularly well suited for pinching and holding objects. Though Atlas was designed to resemble a person in other ways, its hands aren’t exactly one-to-one. Instead, company engineers said, the design was optimized for sorting, packing, and handling objects—all tasks Atlas would need to perform repeatedly in a factory or warehouse setting.

"The goal is to apply as little force as possible while maintaining a stable grasp," Atlas mechanical engineer Karl Price said.

That’s in sharp contrast to the much more seemingly human-like robot hands unveiled by Figure last week. In a flashy video announcing the launch of its knitwear-wearing "Figure 03" model, the company showcases its robots performing delicate tasks like watering a plant, washing dishes, and gently handing a glass of water to their human overlords.

Similar to Tesla with its egg-fondling Optimus robot, Figure has made it clear it envisions a future for humanoid robots in the home. The company describes its latest model as a "general-purpose humanoid robot for everyday use."

But the everyday tasks listed above, as well as many others required of a functional robot butler, pose different engineering challenges than those faced by a machine designed to sort boxes all day. The hands, in other words, offer a clearer glimpse into a robot’s larger place in the world.

Hands might be one of the hardest human body parts to accurately replicate in robotic form. Each one contains more than 30 muscles and 27 joints, enabling 27 degrees of freedom. They also have over 17,000 touch receptors and nerve endings, allowing us to perform a wide variety of actions—from tapping on a keyboard and delicately writing with a pen to hoisting a heavy barbell.

And while robot hands and advanced prosthetic limbs have made significant progress in recent years, none come close to the sophistication, reliability, and innate simplicity of a human hand. That presents a major challenge for humanoid robots, which are increasingly being pitched as tools to augment, or replace, human labor.

"The majority of the hand-led motor actions in these sectors require not only precise movements but also adaptive responses to unpredictable variables such as irregular object shapes, varying textures, and dynamic environmental conditions," University of Florida Professor of Civil Engineering Eric Du told the BBC in an interview earlier this year.