As per Isaac Asimov's First Law of Robotics, "A robot may not injure a human being, or, through inaction, allow a human being to come to harm."
However a robot in central Europe is tasked with hitting people over and over in a bid to induce anything from mild to unbearable pain. Professor Borut Povse is the man behind this mission. He says that by teaching a robot where the human threshold for pain is, we can teach the robot when to stop punching.
He convinced six male colleagues to let the robot that they created punch them in the arm to determine the human robot pain thresholds. He foresees humans and robots working together in the near future and feels that it is important for the robots to know when they hurt the humans. The robot, which was borrowed from Japanese technology firm Epson, was redesigned for the purpose of the research.