This dragon cannot be made by breeding. The Robot Dragon is a dragon which can only be achieved on the Facebook version of Dragon City. To achieve this dragon, you must reach Level 10 or higher in the Facebook game "Social Wars". Once Level 10 is reached, you must go to Dragon City, then click the hatchery,eggs and there will be a button called "Get Dragon!." The dragon can be placed in a Kindergarten, Fire Habitat or Metal Habitat.
"Have you imagined your future with a robot servant? Well, the future is already here and this Robot Dragon is the best servant you can ever get! It even has a container for cold drinks."