A servomechanism may be broadly defined as a closed-loop control system in which a small power input controls a much larger power output in a strictly proportionate manner. In applying such a mechanism to the automatic control of an aircraft, the system must be capable of continuous operation and have the ability to:-
- detect the difference between an input and an output (error detection);
- amplify the error signals; and
- control the closing of the servo loop by providing the feedback.
- position control and
- speed control;
both classes may be independently applied to automatic flight control systems depending respectively on whether they are of the displacement type or the rate sensing type. In some control systems they may also be used in conjunction with each other.
