Explain Servo motor working principal:
Servo motors are used to control position and speed very
precisely, but in a simple case, only position may be controlled.
Mechanical position of the shaft can be sensed by using a potentiometer,
which is coupled with the motor shaft through gears. The current
position of the shaft is converted into electrical signal by the
potentiometer, and the compared with the command input signal. In modern
servo motors, electronic encoders or sensors are used to sense the
position of the shaft.
Command input is given according to the required position of the shaft.
If the feedback signal differs from the given input, an error signal is
generated. This error signal is then amplified and applied as the input
to the motor, which causes the motor to rotate. And when the shaft
reaches to the required position, error signal becomes zero, and hence
the motor stays standstill holding the position.
The command input is given in the form of electrical pulses. As the
actual input applied to the motor is the difference between feedback
signal (current position) and applied signal (required position), speed
of the motor is proportional to the difference between the current
position and the required position. The amount of power required by the
motor is proportional to the distance it needs to travel.