Servomotors

Servomotors are rotary actuators designed to provide precise control of angular position, velocity, and sometimes acceleration. They operate within a closed-loop servomechanism that uses feedback to correct errors between the commanded position and the actual position.

A typical servomotor consists of three main parts: a motor (often a brushed DC motor or a brushless DC motor), a feedback device (such as an encoder, resolver, or potentiometer), and a drive or controller that amplifies the control signal and interfaces with the motor. The controller compares a desired position input with the feedback from the sensor and sends a corresponding drive signal to the motor to minimize the error. In many applications the servo drive is an external unit, while some motors include built-in controllers.

Common types include brushed DC servo motors, brushless DC (BLDC) servo motors, and AC servo motors. Feedback options range from incremental and absolute encoders to resolvers and potentiometers, with the choice affecting accuracy, speed, and robustness. Servomotors are typically used in conjunction with servo drives that manage amplification, motor protection, and performance parameters such as gain, bandwidth, and safety limits.

Applications encompass robotics, CNC machinery, automated manufacturing, and positioning systems requiring high precision and repeatability. The advantages of servomotors include high torque at low speeds, accurate velocity and position control, and rapid dynamic response. Limitations involve higher cost, more complex control electronics, and the need for proper tuning and maintenance of the feedback loop.