Cassie, a bipedal robot that's all legs, has successfully ran five kilometers without having a tether and on a single charge. The machine serves as the basis for Agility Robotics' delivery robot Digit, as TechCrunch notes, though you may also remember it for "blindly" navigating a set of stairs. Oregon State University engineers were able to train Cassie in a simulator to give it the capability to go up and down a flight of stairs without the use of cameras or LIDAR. Now, engineers from the same team were able to train Cassie to run using a deep reinforcement learning algorithm. According to the team, Cassie teaching itself using the technique gave it the capability to stay upright without a tether by shifting its balance while running.