Servomotor is a rotary actuator or linear actuator that allows for precise control of angular or linear position, velocity and acceleration. It consists of a suitable motor coupled to a sensor for position feedback.
It also requires a relatively sophisticated controller, often a dedicated module designed specifically for use with servomotors.Servos are controlled by sending an electrical pulse of variable width, or pulse width modulation, through the control wire.
The input to its control is a signal (either analogue or digital) representing the position commanded for the output shaft.In this animation you get the functioning of a servo motor and how the components of a servo drive system work together. From the content:
The motor is paired with some type of position encoder to provide position and speed feedback. In the simplest case, only the position is measured. The measured position of the output is compared to the command position, the external input to the controller.