In practical usage, a robot is a mechanical device which performs automated tasks, either according to direct human supervision, a pre-defined program or, a set of general guidelines, using artificial intelligence techniques. These tasks either replace or enhance human work, such as in manufacturing, construction or manipulation of heavy or hazardous materials.
A robot may include a feedback-driven connection between sense and action, not under direct human control. The action may take the form of electro-magnetic motors or actuators that move an arm, open and close grips, or propel the robot. The step by step control and feedback is provided by a computer program run on either an external or embedded computer or a microcontroller. By this definition, a robot may include nearly all automated devices. (via Wikipedia)