Servo motors and stepper motors each have their own unique characteristics and application scenarios in Arduino control. The following is a detailed comparison of the two and an explanation of Arduino control:
1. Servo motors
#1. Basic characteristics
* Closed-loop control system: A servo motor is a closed-loop system that uses position feedback (such as an encoder or potentiometer) to control its movement and final position, thereby achieving high-precision position control.
* Low speed and high torque: Servo motors generally have the characteristics of low speed and high torque, which are suitable for application scenarios that require precise position control and stable torque output.
* Angle limit: The rotation angle of traditional servo motors is usually limited to 180 degrees, 270 degrees, or 90 degrees, but there are also continuous rotation servo motors available.
#2. Arduino control
* Connection method: The control line of the servo motor is usually connected to the digital pin of the Arduino, and its angle is controlled by a PWM (pulse width modulation) signal.
* Control signal: The frequency of the control signal is usually 50Hz (that is, a pulse is sent every 20ms), and the pulse width determines the rotation angle of the servo motor. For example, a pulse width of 1ms may correspond to a 0-degree position, 1.5ms to a 90-degree position, and 2ms to a 180-degree position.
* Library usage: The Arduino IDE provides a Servo library that simplifies the control of servo motors. With the Servo library, it is easy to set the target angle of the servo motor and have it automatically rotate to that angle.
2. Stepper Motor
#1. Basic Features
* Open-loop control system: Stepper motors rely mainly on electrical pulse signals to control their rotation angle and speed, and do not require position feedback sensors.
* Precise control: Precise control of the position and speed of stepper motors can be achieved by precisely controlling the number and frequency of pulses.
* Subdivision technology: In order to improve the control accuracy of stepper motors, subdivision technology can be used to further subdivide the step angle.
#2. Arduino control
* Connection method: The control line of the stepper motor is usually connected to the digital pin of the Arduino, and its rotation is controlled by sending a series of pulse signals.
* Control signal: The frequency and number of the control signal determine the rotation speed and angle of the stepper motor. Usually, Arduino generates these pulse signals through a timer or interrupt service program.
* Library usage: Arduino IDE also provides stepper motor control libraries (such as AccelStepper library), which can more conveniently control the rotation of stepper motors.
3. Comparison between servo motors and stepper motors
| | Servo motor | Stepper motor |
| --- | --- | --- |
| Control system | Closed-loop control | Open-loop control |
| Position accuracy | High (guaranteed by encoder or potentiometer) | Higher (can be improved by subdivision technology) |
| Speed control | Accurate but may be limited (determined by motor performance) | Controllable (by pulse frequency adjustment) |
| Torque output | Low speed and high torque | Varies according to model and voltage |
| Application scenarios | Scenarios requiring high-precision position control and stable torque output | Scenarios requiring precise control of position and speed |
4. Arduino control recommendations
* Servo motor: For application scenarios that require high-precision position control and stable torque output, it is recommended to use a servo motor. Arduino's Servo library can simplify the control process and achieve precise angle control.
* Stepper motor: For applications that require precise control of position and speed, such as 3D printers, CNC machine tools, etc., stepper motors are a good choice. Arduino's stepper motor control library (such as the AccelStepper library) can easily implement stepper motor control.
In general, servo motors and stepper motors have their own advantages in Arduino control. Which motor to choose depends on the specific application scenario and requirements.