BigDog was the four-legged robot developed by Boston Dynamics with MIT-related research support for military load-carrying studies in 2008.
Funded in part by the Defense Advanced Research Projects Agency, BigDog was designed to carry equipment over rough terrain where wheeled vehicles could struggle. Its legs used hydraulic actuation, and onboard sensors helped it maintain balance while walking, climbing and recovering from disturbances.
The robot became widely known through videos showing it traversing uneven ground and resisting pushes. Its engine and hydraulic systems made it powerful, but also loud and complex, limiting its suitability for some military missions.
BigDog is not the same machine as Spot, Boston Dynamics’ later commercial quadruped, or Cheetah, a faster research robot. BigDog’s distinctive role was heavy-load mobility and balance on difficult terrain.