Servo Motor

A servomotor is a rotary actuator or linear actuator that allows for high-response, high-precision control of angular or linear position, velocity and acceleration. As a motor capable of the accurate rotation angle and speed control, it can be used for a variety of equipment. They are used in applications such as robotics, CNC machinery or automated manufacturing and are generally used as a high-performance alternative to the stepper motor.

Servo systems combine a high-performance servo motor with a servo amplifier (drive) to achieve the extremely accurate position, velocity, or torque control. Servos have integrated gears and a shaft that can be precisely controlled. The servo circuitry is built right inside the motor unit and has a positionable shaft, which usually is fitted with a gear. The motor is controlled with an electric signal which determines the amount of movement of the shaft.

In a closed loop control, a rotation detector (encoder) is mounted on the motor and feeds the rotation position/speed of the motor shaft back to the driver. The driver calculates the error of the pulse signal or analog voltage (position command / speed command) from the controller and the feedback signal (current position/speed) and controls the motor rotation so the error becomes zero. The closed loop control method is achieved with a driver, motor and encoder, so the motor can carry out highly accurate positioning operations. In a position control system, a controller inputs the pulse signal, the speed and stop position is then controlled according to the pulse number.