The Difference Between Stepper Motor And Servo Motor

Both stepper motors and servo motors play a big role in improving the precision of mechanical equipment control loops. Because the stepper motor has no cumulative error, it is widely used in various open-loop control. And because of their high pole count and ability to generate holding torque, they consume less power at zero speed. The servo motor can convert the received electrical signal into the angular displacement or angular velocity output on the motor shaft, so it is more powerful in terms of performance. This article mainly introduces their differences in working principle, control accuracy, and cost-effective selection.

The difference in Servo Motors and Stepper Motors

Working principle

The nissan altima step motor converts the electrical pulse signal into angular displacement or linear displacement and controls the rotation angle by controlling the number of pulses, one pulse corresponds to one step angle.

The servo mainly relies on pulses to control the angle. The servo motor itself has the function of sending out pulses, so every time the servo motor rotates an angle, it will send out a corresponding number of pulses. In this way, it forms an echo with the pulse received by the servo motor or called a closed loop, so that the system will know how many pulses are sent and how many pulses are received back. Finally, it can accurately control the rotation of the motor and achieve precise positioning.

Control precision

The control precision is different. The accuracy of stepper motors is generally achieved through the precise control of the step angle. The more phases and cypresses, the higher the accuracy. The server motor depends on its own encoder. At present, most servo motors have relatively high precision.

Rotating speed

The speed response is different. It takes hundreds of milliseconds for a stepper motor to accelerate from a standstill to work, while a private motor usually only takes a few milliseconds. Stepper motors are prone to low-frequency vibrations when they run at low speeds, so when stepper motors work at low speeds, damping techniques are usually required to overcome low-frequency vibrations, such as adding a damper to the motor or using subdivision technology on the driver. The servo motor does not have this phenomenon, and its closed-loop control characteristics determine its excellent performance when running at high speed. The torque-frequency characteristics of the two are different, and the rated speed of the general servo motor is greater than that of the stepper motor.

Cost

Comparing the cost performance of the two sides, Progressive Motor has an advantage in terms of cost performance. It usually requires no feedback, uses cheaper magnets, and rarely includes a gearbox. They consume less power at zero speed due to their high number of poles and ability to generate holding torque for the same function. The advantages of high response, high speed and high precision of the servo motor determine the high price of the product. As a result, stepper motors can be an order of magnitude cheaper than comparable servo motors.