Small servo motors are small in size and high in cost - performance. They are mainly used for angle control and are commonly applied in aircraft models, intelligent vehicles, and robots. They also find applications in industries. For example, the pitch, yaw, and roll movements of missile attitude conversion are all accomplished by small servo motors working together. Servo motors have been used in many projects, not only in model airplanes, model cars, industrial equipment, service robots, and logistics for industrial control. The servo circuit is built - in the motor unit, and it has a positionable shaft, usually equipped with a gear box and a motor. There are two types of control: PWM servo signal control and serial - port command control.

What's inside a small servo motor?

A small servo motor is mainly composed of the following components: the servo motor housing, gearbox, potentiometer, small motor, control board, and servo wires. The motor drive is controlled by the width of the PWM pulse. The potentiometer will detect the angle range according to the width of the pulse and drive the motor to complete the driving stroke with a certain travel. Therefore, you can achieve any speed and angle you want for the servo motor.

How to control a small servo motor?

Servo motors are controlled by sending width - modulated signals through PWM pulses. To rotate a 180° or 90° servo motor counter - clockwise, the rotation direction has the same position as the counter - clockwise position of the servo motor or the upward rotation of the motor in the defined neutral position. The position control line is determined based on the continuous sending of pulses. The PWM is transmitted from the motor to the shaft over time; the rotor will rotate to the desired position. The rotation of the motor is determined by the pulse length of 20 milliseconds. One pulse will move the motor to the desired position at a certain interval. For example, a 1.5 - ms pulse will rotate the motor to the 90° position. A shorter pulse, such as 1.0 - ms, will move the position counter - clockwise to 0°. Any position from 0° to 90° can be achieved by moving counter - clockwise. A longer pulse, such as 2.0 - ms, will rotate the mechanism clockwise to the 180° position of the servo.

When a small servo motor is commanded to move, it will move to that position and hold it. If an external force pushes the servo mechanism while it is in position, the servo mechanism will not move from that position. The force that the servo can exert is called the torque rating of the servo. The servo will not hold its position forever; the position pulse must be repeated to indicate that the servo system is still in position.