Final answer:
A servomotor requires an encoder to provide feedback about the position of the machine's axis to the control, enabling precise position and speed adjustments.
Step-by-step explanation:
A device that requires an encoder to provide feedback about the position of the machine's axis to the control is known as a servomotor. Unlike stepper motors, servomotors are not inherently aware of their position. Servomotors rely on external sensors, often called encoders, to provide position and speed feedback to the drive controller. With this feedback, the controller can make precise adjustments to the motor's position, ensuring that the output shaft is at the desired location and moving at the correct speed.
A lead nut and a lead screw are mechanical components part of a linear motion system but do not inherently require feedback for position control. A stepper motor, on the other hand, operates on open-loop control and does not typically require an encoder for regular functioning but can be combined with one for enhanced positioning accuracy.