Asimov's Three Laws of Robotics - from Isaac Asimov's novel I, Robot.
1) A robot may not injure a human being, or, through inaction, allow a human being to come to harm;
2) A robot must obey the orders given it by human beings except where such orders conflict with the First Law; and
3) A robot must protect its own existence as long as such protection does not conflict with the First or Second Law.