Boston Dynamics drops the pinky on new 13-DOF Atlas hand

Boston Dynamics' new Atlas hand has four fingers, not five. It carries 13 degrees of freedom, up from seven on the previous design, and the fifth finger is gone on purpose.

"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," mechanical engineer Dylan Thrush told The Robot Report. Chief Product Officer Zachary Jackowski had teammates tape their pinky and ring finger together for a day to pressure-test the call. They concluded the robot did not need a fifth digit.

The hand uses direct actuation at the joints with a single actuator type, a backdrivable transmission for high-fidelity simulation, dense pressure tactile sensors on the fingertips and palm, and no fragile cables crossing joints. Size is roughly a large human hand. Boston Dynamics says the design is built for mass manufacturing, and that "RL in simulation is an essential component to solve dexterous manipulation," with domain randomization used during training to transfer policies to hardware.

Alberto Rodriguez, director of robot behavior, framed the tradeoff bluntly: "There's always some amount of intuition and experimentation. It boils down to a trade of different competing objectives." Earlier Atlas hands were designed to grasp a variety of objects; this one prioritizes object manipulation and autonomous operation. The target skill set is dexterous pinch grasps, tripodal grasps, and "triggered tool grasps, like drills, power torque drivers, grinders, nail guns, and welding torches."

The reporting does not publish per-task success rates, sim-to-real transfer numbers, a price, or any head-to-head against five-finger rivals. Humanoid hardware has been a recurring thread in our robotics coverage over the last quarter, and this one is less about a new benchmark than a bet on which hand design is actually buildable at volume.