The working principle of the servo motor is relatively simple, but its work is more efficient. The servo circuit is built into the motor unit and uses a flexible shaft that is usually equipped with gears. The electric signal controls the motor and also determines the amount of axis movement. The internal setting of the servo motor is simple: small DC motor, control circuit and potentiometer. The DC motor is connected to the control wheel through a gear. When the motor rotates, the resistance of the potentiometer changes, and the control circuit can precisely adjust the movement and direction.
When the shaft is in the correct (ideal) position, the motor stops supplying power. If the shaft does not stop at the target position, the motor runs until it enters the correct direction. The position of the target is transmitted through a signal line using an electric pulse. Therefore, the speed of the motor is proportional to the actual and ideal position. When the motor approaches the desired position, the motor starts to rotate slowly, but when the motor is turned farthest, the speed is fast. In other words, servo motors only need to complete tasks as quickly as possible, which makes them highly efficient equipment.
There are usually two types of servo motors: AC motors and DC motors. DC servo motors are ideal for small applications but cannot handle large current surges. However, AC servo motors can cope with higher current surges and are widely used in industrial machinery. When it comes to price, DC motors are cheaper than AC servos, so they are used more often. In addition, DC motors are specifically designed for continuous rotation, which makes them ideal for robot motion.
With its unique features, servo motors can be used in many different applications. In radio controlled aircraft, they are used to locate control surfaces such as robots, elevators, rudders, etc. In online manufacturing, servo motors are used in high repetition frequencies and require precise work.