In the 1966 television series Lost in Space, the robot’s official character name was Robot. The mechanical character is often called “Robot,” although the production and later reference works identify it more specifically as Robot B-9.
Robot B-9 travels with the Robinson family after their spacecraft is diverted from its mission to colonize a planet near Alpha Centauri. The robot is programmed for protection and repeatedly helps the family survive dangerous situations on their journey through space.
The character is sometimes informally called “the Lost in Space robot,” which can lead to answers such as Robby the Robot. Robby belongs to the earlier film Forbidden Planet and is a different science-fiction character. The original Lost in Space robot was designed by Robert Kinoshita, who had also designed Robby.