Actuator

An actuator is a component of a machine that produces force, torque, or displacement, when an electrical, pneumatic or hydraulic input is supplied to it in a system (called an actuating system). The effect is usually produced in a controlled way.^[1] An actuator translates such an input signal into the required form of mechanical energy. It is a type of transducer.^[2] In simple terms, it is a "mover".

An actuator requires a control device (which provides control signal) and a source of energy. The control signal is relatively low in energy and may be voltage, electric current, pneumatic, or hydraulic fluid pressure, or even human power^{[clarification needed]}.^[3] In the electric, hydraulic, and pneumatic sense, it is a form of automation or automatic control.

The displacement achieved is commonly linear or rotational, as exemplified by linear motors and rotary motors, respectively. Rotary motion is more natural for small machines making large displacements. By means of a leadscrew, rotary motion can be adapted to function as a linear actuator (which produces a linear motion, but is not a linear motor).

Another broad classification of actuators separates them into two types: incremental-drive actuators and continuous-drive actuators. Stepper motors are one type of incremental-drive actuators. Examples of continuous-drive actuators include DC torque motors, induction motors, hydraulic and pneumatic motors, and piston-cylinder drives (rams).^[4]

^ Escudier, Marcel; Atkins, Tony (2019). "A Dictionary of Mechanical Engineering". Oxford Reference. doi:10.1093/acref/9780198832102.001.0001. ISBN 978-0-19-883210-2.
^ Butterfield, Andrew J.; Szymanski, John, eds. (2018). "A Dictionary of Electronics and Electrical Engineering". Oxford Reference. doi:10.1093/acref/9780198725725.001.0001. ISBN 978-0-19-872572-5.
^ Nesbitt, B. (2011). Handbook of Valves and Actuators: Valves Manual International. Elsevier Science. p. 2. ISBN 978-0-08-054928-6. Retrieved 2021-11-11.
^ Clarence W. de Silva. Mechatronics: An Integrated Approach (2005). CRC Press. p. 761.

[1] Escudier, Marcel; Atkins, Tony (2019). "A Dictionary of Mechanical Engineering". Oxford Reference. doi:10.1093/acref/9780198832102.001.0001. ISBN 978-0-19-883210-2.

[2] Butterfield, Andrew J.; Szymanski, John, eds. (2018). "A Dictionary of Electronics and Electrical Engineering". Oxford Reference. doi:10.1093/acref/9780198725725.001.0001. ISBN 978-0-19-872572-5.

[Nesbitt_2011_p._2-3] Nesbitt, B. (2011). Handbook of Valves and Actuators: Valves Manual International. Elsevier Science. p. 2. ISBN 978-0-08-054928-6. Retrieved 2021-11-11.

[4] Clarence W. de Silva. Mechatronics: An Integrated Approach (2005). CRC Press. p. 761.

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