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of a petrol engine to work a quarter-turn oscillating vane actuator. Such windscreen wipers worked adequately when the engine was running under light load, but they were notorious that when working hard at top speed or climbing a hill, the manifold vacuum was reduced and the wipers slowed to a crawl.
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that identifies the position of the output shaft and an inbuilt control system. The input control signal to the servo indicates the desired output position. Any difference between the position commanded and the position of the encoder gives rise to an error signal that causes the motor and geartrain
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Stepper motors are a form of electric motor that has the ability to move in discrete steps of a fixed size. This can be used either to produce continuous rotation at a controlled speed or to move by a controlled angular amount. If the stepper is combined with either a
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Both hydraulic and pneumatic power may be used to drive an actuator, usually the larger and more powerful types. As their internal construction is generally similar (in principle, if not in size) they are often considered together as
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Rotary actuators are used in a vast range of applications. These require actuators of all sizes, power and operating speed. These can range from zero power actuators that are only used as display devices, such as
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is a packaged of several components: a motor (usually electric, although fluid power motors may also be used), a gear train to reduce the many rotations of the motor to a higher torque rotation, a
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The simplest actuator is purely mechanical, where linear motion in one direction gives rise to rotation. The most common actuators are electrically powered; others may be powered
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is available, but not pneumatic power, rotary actuators have even been made to work from vacuum power. The only common instance of these was for early automatic
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or at least a single datum sensor at the zero position, it is possible to move the motor to any angular position and so to act as a rotary actuator.
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actuators. Fluid power actuators are of two common forms: those where a linear piston and cylinder mechanism is geared to produce rotation (
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Zero power actuators are those, such as display gauges, that do not deliver a tangible output torque
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The motion produced by an actuator may be either continuous rotation, as for an
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to rotate until the encoder reflects a position matching that commanded.
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A recent, and novel, form of ultra-lightweight actuator uses
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331:"What is a Rotary Actuator and how are they Used"
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253:that operate pipeline and process valves in the
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289:"Nanomuscle rotary actuator"
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313:"Rotary actuator designs"
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92:Actuator power sources
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191:Fluid power actuators
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296:SparkFun Electronics
223:Where a supply of
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167:A simple low-cost
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97:Electric actuators
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23:Electric rotary
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36:rotary actuator
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86:torque motor
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333:. Firgelli.
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209:fluid power
185:memory wire
179:Other types
132:Servomotors
78:servomotors
261:References
157:servomotor
151:servomotor
65:stored in
46:motion or
350:Actuators
61:, or use
344:Category
40:actuator
16:AE motor
67:springs
225:vacuum
63:energy
48:torque
44:rotary
38:is an
292:(PDF)
169:servo
144:servo
80:and
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