Robot uses servo motors and servomechanisms.

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Components of Robots:

The actuators are the 'muscles' of a robot; the parts which convert stored energy into movement. By far the most popular actuators are electric motors, but there are many others, some of which are powered by electricity, while others use
chemicals, or compressed air.

• Motors: By far the vast majority of robots use electric motors, of which there are
  several kinds. DC motors, which are familiar to many people, spin rapidly when an electric
  current is passed through them. They will spin backwards if the current is made to flow in the other direction.
• Stepper Motors:
  As the name suggests, stepper motors do not spin freely like DC
  motors, they rotate in steps of a few degrees at a time, under the
  command of a controller. This makes them easier to control, as
  the controller knows exactly how far they have rotated, without having
  to use a sensor. Therefore they are used on many robots
  and CNC machining centres.

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Hello could you tell me how a robot moves