At the height of this conflict, Robotnik died during a final confrontation with Sonic, but was later replaced by another Robotnik from a parallel world, becoming the same Dr. Eggman from the video games.
That was the name of the character, but when the game got localized and ported into the Sonic the Hedgehog that we know in the West, they decided to, without confirming with the development team, change his name to Ivo Robotnik or just Robotnik.
The "SatAM" Sonic the Hedgehog series' portrayal of Dr. Ivo Robotnik (Eggman in the various video games) was a radical change from the incompetent and comical baddie from the "Adventures of Sonic the Hedgehog" program and provided a much more elaborate design than his gaming counterpart.