Boston Dynamics Unveils New Four-Fingered Atlas Humanoid Hand

Boston Dynamics has unveiled the newest hand for its Atlas humanoid, featuring four fingers, 13 degrees of freedom (DOF), direct actuation, and a design optimized for mass manufacturing.

Previous versions of the Atlas hand featured seven degrees of freedom and were built to grasp a wide variety of objects. With the latest design, the company is shifting its focus toward manipulating those objects.

"We considered many, many designs, and there were many questions like: Do we want the hand to have one thumb or two thumbs? Do we really want the hand to have a pinky or not? And most of these don't have straight answers," said Alberto Rodriguez, director of robot behavior for Atlas. "There's always some amount of intuition and experimentation. It boils down to a trade of different competing objectives."

The four-fingered hand, which omits a pinky finger, is built for high-fidelity simulation to enable sim-to-real reinforcement learning (RL). The company maintained transparent direct actuation at the joints using a single actuator type, with actuators fully encapsulated and no fragile cables crossing joints.

"There's no pinky because the team determined that the additional dexterity and tasks you'd be able to accomplish is not worth the extra complexity of three additional degrees of freedom, the size, the power consumption, all of the things that come with adding additional actuators," said Dylan Thrush, a mechanical engineer on the Atlas team.

The hand is capable of sliding the thumb fingertip along the length and width of all other fingers, dexterous pinch and tripodal grasps, and triggered tool grasps for drills, power torque drivers, grinders, nail guns, and welding torches. It also supports in-hand reorientation, recovery from slipping grasps, and tool handling while pressing triggers.

Atlas' new hand is similar in size to a large human hand, with a thumb featuring four DOFs and the other three fingers each featuring three DOFs. Dense pressure tactile sensors cover the fingertips and palm, complementing proprioception for agile dexterous behaviors.