In plain words
A robot is a machine that does physical work on its own. Britannica's definition is broad: any automatically operated machine that replaces human effort. It does not have to look like a person. Many are arms bolted to factory floors.
Every robot runs the same loop. It senses the world through cameras, touch sensors or wheels that count turns. It decides what to do. Then it acts, using motors to move. Then it senses again to see what changed.
Robotics is the field that designs and builds these machines, mixing mechanical engineering, electronics and software.
Not every robot uses AI. A classic welding arm repeats the same programmed motion all day. AI comes in when a robot must cope with a messy, changing world, like recognising a dropped sock or walking round a cat. That newer side is often called physical AI.
Everyday example
A robot vacuum cleaner
A robot vacuum leaves its dock. A bumper and distance sensors tell it there is a sofa ahead. Its small computer decides to turn left. Its wheel motors turn it. A moment later it senses again: clear floor, so it moves forward. Sense, decide, act, repeat, many times a second, until the room is done and it heads home to charge.
Where the example breaks: A vacuum only has to avoid things and cover the floor. Robots that pick up objects, work beside people or walk on two legs face far harder choices, where one wrong move can break something or hurt someone.
How it actually works
Robotics courses describe a robot as a sense, think, act loop repeated until the task is done.
Sense
Sensors connect the real world to the robot's internal picture of it: cameras, depth sensors, microphones, touch and force sensors, and encoders that measure how far each joint or wheel has turned.
Think
Software works out where the robot is, what is around it and how to reach the goal. Here AI can help: computer vision spots objects, and planning software chooses a path that avoids them.
Act
Motors and other actuators (parts that create movement) carry out the plan. Control software keeps checking and correcting, so an arm stops at the right spot instead of overshooting.
Programmed or learned
Traditional industrial robots follow exact programmed paths in fenced-off cells. Newer robots increasingly learn skills from data, demonstrations and simulation using machine learning, so they can handle objects and places they were not explicitly programmed for.
- The word robot
- From Czech "robota" (forced labour), used in Karel Čapek's 1920 play R.U.R.
- The word robotics
- Coined by Isaac Asimov in his story "Liar!" (1941)
- First industrial robot
- Unimate, 1961, at a General Motors plant in New Jersey, lifting hot metal parts from a casting machine
- Factory robots today
- About 5 million in operation worldwide in 2025, per the International Federation of Robotics. China installed about 59% of new ones; India ranked sixth
Questions people ask
What is the difference between robotics and AI?
Robotics is about machines that act in the physical world. AI is about software that does tasks that seem to need intelligence. A chatbot is AI with no body. A simple factory arm is a robot with no AI. Robots that see, learn and adapt combine the two.
Are all robots AI?
No. Many robots, including most traditional factory arms, follow fixed programs with no learning at all. They are precise and fast but cannot cope with surprises. AI is added when a robot needs to recognise things, handle variety or learn new tasks.
Where does the word robot come from?
From the Czech word "robota", meaning forced labour. Karel Čapek used it in his 1920 play R.U.R., about manufactured humans who revolt. The word "robotics" came later, coined by the science fiction writer Isaac Asimov in a 1941 story.
How many robots are there in the world?
For factory robots, the International Federation of Robotics counted a record 5 million in operation worldwide in 2025, with more than 600,000 installed that year. Counts of home robots, like vacuum cleaners, are kept separately and vary by source.