A robot is a machine that can sense what is around it, decide what to do, and then do it. It has sensors to find out about the world. It has a computer to decide. It has motors, called actuators, to move. Sensors can be cameras and touch sensors. A robot vacuum has a touch sensor in its bumper to find its way around a room. The computer uses what the sensors tell it to decide what to do next. Then it drives the motors.

A robot vacuum cleaner drives itself around a home and cleans the floor. Its sensors help it avoid bumping into things and falling down stairs. Some robot vacuums build a map of the home. That way they can clean every spot. A robot vacuum can go back to its charging station by itself. Many robots carry their own energy source, such as a battery. They are not plugged into a wall.

The first factory robot arm went to work in 1961 at a General Motors car plant in New Jersey. It was named Unimate. Its job was moving finished metal castings. That was a dirty and dangerous job that people no longer had to do. About 5 million industrial robots were working in factories around the world in 2025. Factories put in more than 600,000 new ones that year, up 11% from the year before.

Robots often do jobs that are dangerous, hard or boring for people. Robot arms in car factories do jobs such as welding, painting and putting parts on cars. Robots do jobs that people would rather leave to machines. That keeps people out of danger. In robotic surgery, a doctor sits at a console and moves robot arms that hold tiny tools. Robotic surgery does not replace the surgeon. The surgeon controls the robot arm.

Many robots follow programs that tell them how to do a specific job, such as moving from one place to another. Many factory robots do the same action again and again, the same way each time. Some jobs are easy for people but hard to program into a robot. Moving around, seeing and grasping things are some of them. A robot has trouble picking up an actual chess piece. A computer can beat a chess grandmaster. A robot that walks on legs can fall over. A hard enough push can topple it.

The word robot comes from a play that was written long ago. The play is called R.U.R., which stands for Rossum's Universal Robots. The Czech word robota means forced work. Karel Čapek said that his brother Josef, an artist, came up with the word. The writer Isaac Asimov imagined Three Laws of Robotics in his science fiction stories. The laws are part of his stories. Experts do not all agree on exactly what counts as a robot.

Words to know

• sensors: parts that sense
• actuators: motors that move
• castings: finished metal pieces
• grandmaster: top chess player
• robota: forced work