Servo Motor Theory
There are some special types of application of electric motor where rotation of the motor is required for just a certain angle. For these applications, we require some special types of motor with some special arrangement which makes the motor to rotate a certain angle for a given electrical input (signal). For this purpose servo motor comes into picture.
The servo motor is usually a simple DC motor controlled for specific angular rotation with the help of additional servomechanism (a typical closed-loop feedback control system). Now day’s servo system has large industrial applications. Servo motor applications are also commonly seen in remote-controlled toy cars for controlling the direction of motion, and it is also very widely used as the motor which moves the tray of a CD or DVD player. Besides these, there are other hundreds of servo motor applications we see in our daily life.
The main reason behind using a servo is that it provides angular precision, i.e. it will only rotate as much we want and then stop and wait for next signal to take further action. The servo motor is unlike a standard electric motor which starts turning as when we apply power to it, and the rotation continues until we switch off the power. We cannot control the rotational progress of electrical motor, but we can only control the speed of rotation and can turn it ON and OFF. Now we come to the specific answer to the question “what is servo motor?”
Servo motor is a special type of motor which is automatically operated up to a certain limit for a given command with the help of error-sensing feedback to correct the performance.