A servo motor 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. Servomotors are used in applications such as robotics, CNC machinery or automated manufacturing.
Servo systems consist of four main components: a motor, a drive, a controller, and a feedback device, which is typically an encoder. The controller and drive work together to determine what the motor needs to do (the controller) and send the necessary electrical energy to the motor to make it happen (the drive).
As the “brains” of the system, the controller’s job is to take information from the feedback device and send the appropriate voltage signals to the drive. The drive acts as the “nervous system” and sends the necessary amount of current to the motor. This process of reading and responding to feedback makes the system “closed loop,” which is the defining characteristic of a servo system.