Stepper motor with encoder for feedback which is also known as closed-loop stepper motor
Closed-loop Stepper Motor, Stepper Driver 2 or 3 phase 1.2 or 1.8 step angle and CANopen Stepper Controller, Servo Stepper Motor Solutions.
AC Servo Motor
40, 60 or 80 AC Servo Motor
Coreless or Brushless Servo?
RC Servo, Robot Servo, 12V Industrial Coreless or Brushless Servo?
The steering gear 'SERVO' is a common name for Chinese people, because the model airplane enthusiasts first used it to control the rudder and the aircraft's rudder surface. The English of the servo motor is servomotor. What about the steering gear? Some people also call it as servomotor which is short as servo. Probably the relationship between "servo motor" and "small servo". From the structure analysis, the steering gear includes a small DC motor (Latest Coreless or Brushless Motor), plus sensors, control chips, reduction gear sets, and fit into the integrated casing. The angle of rotation can be controlled by an input signal (typically a PWM signal or a digital signal). Because it is a simplified version, the three-loop control of the original servo motor is simplified into a loop, that is, only the position loop is detected. The cheap solution is a potentiometer, which is detected by a resistor. The advanced scheme uses a Hall sensor or a grating encoder. Many of the steering gears used for the model are simply plastic casings plus plastic gear sets. For example, the famous cheap steering gear SG90, commonly known as 9g steering gear (because the weight is 9g)