How AI taught Cassie the two-legged robot to run and jump

Researchers used an AI technique called reinforcement learning to help a two-legged robot nicknamed Cassie to run 400 meters, over varying terrains, and execute standing long jumps and high jumps, without being trained explicitly on each movement. Reinforcement learning works by rewarding or penalizing an AI as it tries to carry out an objective. In this case, the approach taught the robot to generalize and respond in new scenarios, instead of freezing like its predecessors may have done. "We wanted to push the limits of robot agility," says Zhongyu Li, a PhD student at University of California, Berkeley, who worked on the project, which has not yet been peer-reviewed. "The high-level goal was to teach the robot to learn how to do all kinds of dynamic motions the way a human does."