rotary actuator vs positioner

rotary actuator and positioner both are nouns.

Word	Noun	Adjective	Verb	Adverb
rotary actuator	Yes	No	No	No
positioner	Yes	No	No	No

As nouns, rotary actuator and positioner are synonyms defined as:

rotary actuator and positioner: (computer science) the actuator that moves a read/write head to the proper data track

rotary actuator (noun)	positioner (noun)
(computer science) the actuator that moves a read/write head to the proper data track	(computer science) the actuator that moves a read/write head to the proper data track
	a device used to control the opening or closing of the actuator based on electric, or pneumatic signals.