No legs but a bat: the AthenaZero robot hits 82% of baseballs thrown at 13.4 m/s

The robot throws a tennis ball at 30.8 m/s and a baseball at 21.4 m/s. It catches balls arriving at up to 13.4 m/s, and at that speed it hits 82% of them with a bat.

To focus on these movements, the researchers left it without legs or wheels. AthenaZero is just a torso and arms fitted with hands: it cannot move around and can only pivot on the spot.

Its structure is rigid, but its joints give slightly under external forces. This lets the robot absorb the shock when it catches a ball, and its movements become smoother.

The researchers acknowledge some limits. The robot is less precise than conventional machines, and its wrist lacks the range of motion to reproduce human movements when it swings the bat. They say this is only a first prototype.