Thursday, June 13, 2024

The closed loop stepper motor VS servo motor

There are significant differences between closed-loop stepper motors and servo motors in terms of control methods, accuracy, speed response performance, overload capability, operating performance and price.

1.control method:

Closed-loop stepper motors usually use an open-loop control system to control the rotation angle by controlling the number of pulses. Each pulse corresponds to a fixed step angle. This control method makes the movement of the stepper motor discrete and can accurately control the position of each step.

Servo motor

The servo motor uses a closed-loop control system to control the rotation of the motor through real-time position feedback. The encoder monitors the actual position of the motor rotor and feeds this information back to the controller. The controller compares the input position command and adjusts the motor based on the difference to achieve precise motion control.


The accuracy of a closed-loop stepper motor depends on the number of phases and the subdivision setting of the driver, while the accuracy of a servo motor depends on the resolution of the encoder, and generally the accuracy of a servo motor is higher than that of a stepper motor.

3.Speed ​​response performance:

It takes 200 to 400 milliseconds to start a closed-loop stepper motor, while it only takes a few milliseconds for a servo motor to start, showing the servo motor's advantage in speed response performance.

Closed-loop stepper motor

4.Overload capacity:

Closed-loop stepper motors generally do not have overload capability and are prone to losing steps when the starting frequency is too high or the load is too large. In comparison, servo motors have stronger overload capabilities.

5.Running performance:

The closed-loop stepper motor is open-loop controlled and will not lose steps or overshoot, but it is prone to low-frequency vibration at low speeds. The AC servo motor runs smoothly and does not vibrate even at low speeds. Servo systems will outperform stepper motors in many performance aspects, but will also be more complex to control.


Servo motors are more expensive than closed-loop stepper motors, but this price difference is not entirely a shortcoming of servo motors, but reflects their technical complexity and high performance.

To sum up, closed-loop stepper motors and servo motors each have their own advantages and applicable scenarios. Closed-loop stepper motors are suitable for applications that require precise control of the position of each step, while servo motors are suitable for applications that require high-precision positioning and high-speed response performance. Which motor type you choose depends on specific application needs and budget considerations.

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