Robo-Chan

Robo-Chan is a Japanese anime series based on the 1977 single written and produced by Waku Yaniko and released by Pony Canyon.

Plot
Nana Furuka (also known as Robo-Chan) is a 20-year old robot designed after a child actress who was released from her creator because he deemed her "useless". While she was flying, Nana noticed a doctor being harassed by muggers and attacked them to save him. After saving the doctor who introduced himself as Takashi Kuro, Nana decided to live with him as a daughter-figure to him while protecting him (and anyone) from danger.