I used to watch it as a kid. Ultraman was not a robot though, he was a human that gained superpowers through some kind of magic "wand." He could be either regular human-sized or become bigger, depending on the attacking foe. There was also a similar show called Johnny Soko and his Giant Robot. He fought the same kind of enemies, the huge Godzilla-type monsters. They used to alternate these two shows each day on the channel that I saw them on. They were both Japanese made with dubbed English.