Boston Dynamics has detailed a new hand for its Atlas humanoid, moving from seven directly actuated degrees of freedom to thirteen. It has four fingers and an opposable thumb, with no pinky, a choice the company says it settled on after testing suggested the fifth finger did not justify the added complexity. Dense pressure tactile sensors cover the fingertips and palm.
Boston Dynamics describes the hand as similar in size to a large human hand, slightly larger and stronger than average, and says it can carry a loaded minifridge of more than 100lb. The grasps it lists include pinch and tripodal grips and triggered tool grasps for drills, power torque drivers, grinders, nail guns and welding torches.
The less visible engineering choice is the more interesting one. Direct actuation with a backdrivable transmission gives the hand proprioceptive feedback, and the company says the design was picked partly because it simulates with high fidelity, which is what makes sim-to-real reinforcement learning practical.
Why it matters: hands have been the bottleneck in humanoid robotics for years. Balance and locomotion are largely solved; working in a cluttered, unforgiving space is not. A hand built so that policies can be learned in simulation, rather than programmed grip by grip, is the consequential half of this.