Czech playwright Karel Capek introduced the word "robot" to the world in his 1921 play "R.U.R.", or "Rossum's Universal Robots," according to the Literary Encyclopedia. A robot is a machine but not an ordinary one. It has an extra class of functionality to an equivalent machine, has at least some computer components and may possess functions approaching intelligence.
Robotics expert Maja J. Mataric characterizes a robot as being autonomous, or self-governing, at least to some extent. This means it is capable of making decisions. An ordinary machine, such as an electric drill, is not capable of making decisions, although in time, electric drills might be able to decide the best speed to rotate the drill bit for maximum drilling efficiency. Robots are already at this stage, according to Mataric.
Unlike an ordinary machine, a robot often has sensors, such as light sensors. These give the robot additional functionality, acting in part like human senses. This feature is even reflected in some toy robots, such as the Lego Mindstorms NXT system, which includes touch sensors, an ultrasonic sensor for motion detection and even a color sensor. NASA's Mars Rover has four engineering hazcams. These are hazard avoidance cameras, akin to eyes, to prevent it from getting lost or crashing into large boulders.
A robot can use data collected from its sensors to detect when a state has changed and then take appropriate actions. For example, if a robot had a rain detector on its head, it could activate a head umbrella when rain began to fall. The Massachusetts Institute of Technology (MIT), a world authority on the subject, believes this kind of response is artificial intelligence rather than real intelligence, yet concedes some robots are much better than humans at some things.
Robots are often humanoid, or similar to humans in appearance, such as Honda's ASIMO robot. Ordinary machines are not. All machines and robots that have ever been made on Earth are human creations. However, if you believe the prophecies of science fiction, perhaps one day, robots will be intelligent enough to build their own machines and design themselves too. Hopefully, the current peaceful relations between man and robots will continue.