IHMC admitted in the video description that the video was a “lucky run” and that the robot usually doesn’t manage to hold its balance for very long.
The humanoid robot Atlas balancing on a line contact (plywood edge approx. 2cm thick). This video was recorded during a lucky run, usually the robot is not able to maintain balance for this long. The shaking is caused by poor state estimation (we only use onboard sensors). The control algorithm is developed by IHMC the robot was built by Boston Dynamics.