Spare Parts (2015) - http://www.imdb.com/title/tt3233418/
Also, I'm reluctant to call it an underdog story. It's more a "coming of age" story, which is a different thing. There are many, many emotional aspects to the film (family dynamics - multiple generations in a home, absent father or a deported mother) which serve to enhance the overall themes of what happened.
Lastly, it's one of the few films I've seen recently that doesn't rely on CGI to show off important parts of the story. As the credits indicated, there were teams of robotics professionals who built the units used in the film.
I recommend the film and will buy it to have in my house to put on in the background when the mood strikes me. Others that fit that bill for me are Rush, Shawshank Redemption, The Crow, and The Big Lebowski. YMMV.