Going the distance: Digit’s evolution

A major step in the evolution of our bipedal robot Digit originated with its predecessor Cassie. In 2021, Cassie was the first bipedal robot to complete an outdoor 5K. The robot’s innovative mechanical design (its legs resemble those of an ostrich) provided the foundation for the machine learning algorithm that enables it to walk and run. 

Cassie completed the 5K, just over 3 miles, on the campus of Oregon State University, on a single battery charge in 53 minutes, a fairly fast pace for a robot – or a human. Cassie doesn’t have tendons or ligaments to control the release of kinetic energy when walking. Instead, Cassie has springs and actuators that act according to the same principle of storing and releasing energy, and controlling the force of impact, as Cassie’s foot hits the ground.

Walking more than three miles outdoors requires some significant technological achievements. Engineered legs that can carry a robot across variable terrain, both efficiently and with stability. A battery that can store enough energy to power a robot over that distance. And the ability of a robot to navigate an unmapped environment. This combination of advancements propelled Cassie to set a new record for bipedal robots and really go the distance.