The terms like servo or servo-mechanism apply to those response control system which contains:
- Mechanical position, or
- Time derivatives e.g. velocity and acceleration.
These are the following characteristics of a feedback control system:
- excellent accuracy;
ii Able to response fast;
iii. Can be operated by remote;
Following are the necessities of a feedback control system:
- An error detecting device-
It is important because it checks the quantity which is unlike from the reference amount and directs the error signal to the amplifier.
- An amplifier–
It accepts the error signal,gives power to the error-correcting device, which converts the fixed quantity to maintain a link with the reference input.
A servo-motor should need the following characteristics:
- An output torque of the motor which should be proportionate to the voltage present i.e. the amplifier generates control voltage as a response to an error signal.
- Torque direction is influenced by the control voltage instantaneous polarity.