Why does my mother want to move into a camper in my backyard?

I'm 33 with child, have my own place. I've moved several times b/c my mother keeps trying to move in with me! now I cant move b/c Im buying this place. I love my mother, but she drives me crazy and tries to undermine everything I do with my child. Please Help! Need serious advice. I dont want to hurt her but Im at my wits end! Why is she doing this?