A robot is a machine that can sense what is around it, decide what to do, and then do it. Even so, experts do not all agree on exactly what counts as a robot. A NASA robotics engineer describes a robot as a smart, reprogrammable mechanism. It is able to interact with its environment. A robot is not only a machine that can do something physical. It also contains a computer that can control and adapt how it works. A person may control it remotely. Or it may respond to its surroundings by itself.
A robot uses sensors, such as cameras and touch sensors, to find out about the world around it. Robots move and do jobs with parts called effectors. Arms and grippers handle things. Wheels, tracks and legs let the robot move. Robots need a power source, such as motors or hydraulics. They also need a way to send information, such as a wireless connection. A remote-control toy airplane is not a robot, because it has no sensors and a person has to control every move. A drone can be flown by a person with a remote. It can also fly by itself on a programmed course.
Is a drone a robot? One that flies a programmed course, avoids obstacles and lands by itself counts as a robot. In the United States, drone pilots must follow rules and safety tips, because drone safety is the law. Is a microwave oven a robot? It has motors, sensors and a computer. Still, most people would not call it a robot. A Roomba is a robot vacuum. It has infrared sensors pointing down. They help it tell where stairs and steep drops are, so it does not fall down them. It uses onboard sensors the way people use their five senses.
The Roomba went on sale in 2002. Its company sold one million Roombas in just over two years. When its job is done or its battery is low, a Roomba goes back to its charging station by itself. What about robots in hospitals? A surgical robot has three main parts. They are robot arms that hold tiny instruments, a camera, and a console where the surgeon controls the instruments and the camera. The benefits of robotic surgery can include less pain, less bleeding, a shorter hospital stay and smaller scars. Robotic surgery does not replace the surgeon. The surgeon controls the robot arm.
Factory robots do jobs such as moving materials, assembling parts, welding, loading machines and painting. OSHA describes an industrial robot as a programmable, multifunctional mechanical device. It is built to move material, parts, tools or special devices through programmed motions. The inventor George Devol filed a patent in 1954 for a general-purpose arm to do repetitive tasks. A worker who steps inside a factory robot's working envelope can be hurt if the robot makes an unintended move. Robots protect people from injury by doing dangerous jobs in their place. That is one of the most important jobs robots do.
What about robots in space? The Canadarm is a remote manipulator arm that was used on NASA's space shuttle. It is an example of a well-known robot. Canadarm2 can grab spaceships. These ships bring food, spare parts and science experiments to the space station. As of November 2026, NASA has sent five robot rovers to Mars. They are Sojourner, Spirit, Opportunity, Curiosity and Perseverance. Sojourner traveled about 330 feet over 83 days on Mars in 1997. Mars is the only planet we know of that is home to robots and no people. Real robots are made mainly to help people, not to be movie monsters.
Words to know
- effectors: movers and handlers
- hydraulics: liquid power parts
- drone: flying machine
- envelope: robot work zone
- manipulator: robot arm
