Definition and working principle of stepper motor

A stepper motor is an open-loop control component that converts electrical pulse signals into angular or linear displacement. Its working principle is based on electromagnetic principles, precisely controlling the rotation angle and speed of the motor by controlling the frequency and quantity of pulse signals. The rotation of a stepper motor is carried out step by step at a fixed angle, which is called the "step angle". The control accuracy of a stepper motor depends on the size of the step angle, and the smaller the step angle, the higher the control accuracy. For example, a stepper motor with a step angle of 1.8 ° will rotate 1.8 ° for each pulse signal received. The characteristic of stepper motors makes them very useful in applications that require precise positioning, such as the movement of printer heads and precise control of robotic arms.

A servo motor is a type of motor in a closed-loop control system that controls its speed and position through feedback signals. A servo motor typically consists of a motor, encoder, controller, and power supply. The encoder is used to measure the position and speed of the motor, and the controller adjusts the motor's motion based on the feedback signal from the encoder. Servo motors have high control accuracy and can achieve high-speed and high-precision motion. The working principle of servo motors relies on precise feedback mechanisms. The feedback signal provided by the encoder enables the system to adjust the motor's operating status in real time to achieve the predetermined position and speed. This closed-loop control method enables servo motors to perform excellently in applications that require high precision and dynamic response, such as CNC machine tools and robotic arms.

The control methods of stepper motors and servo motors differ significantly. The open-loop control method of stepper motors gives them advantages in cost and simplicity, but there are limitations in speed control and dynamic response. In contrast, although the closed-loop control method of servo motors has increased in cost and complexity, it provides higher control accuracy and dynamic response capability. In practical applications, the choice of motor depends on the specific requirements of the application, including the required control accuracy, speed range, dynamic response, and cost budget. For example, in applications that require fast and precise positioning with low speed control requirements, stepper motors may be a cost-effective choice; In applications that require high precision and fast dynamic response, servo motors are more suitable.