What is a servo actuator and how does it work in flight control systems?

What is a servo actuator and how does it work in flight control systems?

• A. Converts hydraulic pressure to mechanical motion to move control surfaces.
• B. Converts electrical signals to mechanical motion to move control surfaces.
• C. Stores hydraulic fluid.
• D. Controls ignition timing.

Answer: (B)

A servo actuator is an electrical-to-mechanical converter that provides precise, controllable movement of a flight control surface. The flight control computer sends a command signal representing the desired surface position. A servo drive powers a small electric motor inside the actuator, and through gearing or direct drive that motion is converted to the needed surface movement via a pushrod. A position sensor (such as a potentiometer or encoder) feeds the actual surface position back to the control system, forming a closed loop that continually compares commanded and actual positions and adjusts the motor current to minimize error. This combination of an input signal, motor-driven motion, and real-time position feedback gives servo actuators their precision and repeatability in flight control. This is different from hydraulic actuation, which uses fluid pressure to move surfaces, and from components that merely store hydraulic fluid or that control ignition timing.

A servo actuator is an electrical-to-mechanical converter that provides precise, controllable movement of a flight control surface. The flight control computer sends a command signal representing the desired surface position. A servo drive powers a small electric motor inside the actuator, and through gearing or direct drive that motion is converted to the needed surface movement via a pushrod. A position sensor (such as a potentiometer or encoder) feeds the actual surface position back to the control system, forming a closed loop that continually compares commanded and actual positions and adjusts the motor current to minimize error. This combination of an input signal, motor-driven motion, and real-time position feedback gives servo actuators their precision and repeatability in flight control.

This is different from hydraulic actuation, which uses fluid pressure to move surfaces, and from components that merely store hydraulic fluid or that control ignition timing.