According to NASA - JSC Learning Technologies, the characteristics that make robots different from regular machinery are:
Robots usually function by themselves.
They are sensitive to their environment.
They adapt to variations in the environment or to errors in prior performance.
They are task oriented.
They often have the ability to try different methods to accomplish a task.
A robot can be defined as a programmable, self-controlled device consisting of electronic, electrical, or mechanical units.
Current robots have advanced sensory systems that process information and appear to function as if they have brains. Their "brain" is actually a form of computerized artificial intelligence (AI). AI allows a robot to perceive conditions and decide upon a course of action based on those conditions.
A robot can include any of the following components:
effectors - "arms", "legs", "hands", "feet"
sensors - parts that act like senses and can detect objects or things like heat and light and convert the object information into symbols that computers understand
computer - the brain that contains instructions called algorithms to control the robot
equipment - this includes tools and mechanical fixtures
To learn more about robots, its types and history, visit NASA - JSC Learning Technologies.
Check out 10 Tips for Getting Started with Robotics, shared by RobotShop Blog.