What is an Actuator?

Actuators

Actuator are typically part of  devices that help achieve movement by transforming energy (usually electric, air, or hydraulic) into mechanical power. In other words, it's the part in almost any device that allows movement.

Actuator exploded view

Actuators are all around us and used in virtually every device that create motion in linear for or even rotational form,  You will find them in cars, plates boats, household appliances, industrial robots and many other things.   The nee Proposed Tesla-BOT for example is expected to use 46 Electro-Mechanical Actuators.

 

 

 

 

 

 

actuator machine     actuator

What is an Electro-Mechanical Linear Actuator?

A linear actuator is a device that transforms rotational motion into linear motion - straight lime movement basically.  These linear actuator movements can be powered by electric, hydraulic, or pneumatic energy.  Electric actuators, for example operate on the input of DC or AC voltages.  Other types include Hydraulic actuators that use  incompressible liquid to form extremely high forces, and pneumatic actuators that use air, can provide fast acting actuators at a lower force.

Commonly used I n industrial motion control systems, actuators are entirely responsible for ensuring devices like robotic arms can move when a signal input  is supplied to the robot. All vehicles use actuators in many different ways from trunk lid opening automatically to engine control system for the fuel injectors. 

How do Linear Actuators Work?

Hydraulic Linear Actuators

Hydraulic linear actuators as used in industrial application provide extremely high forces. This is why they are solely used in tractors, diggers etc.  Hudraulic Actuators provide straight line motion by using high Pressire a hydraulic pumps that supply high pressure Hudraulic fluid to a cylinder with a piston in it that slides in and out.   The pressure available to these types of actuators can be huge as the larger the cylinder diameter the higher the pressure that can be gained. Using solenoid valves the pressure can then be applied to the other side of the piston head to make the actuator slide in the opposite direction 

Hudraulic Actuators have many advantages but they are also very costly, require heavy duty pumps and a specific non compressible hydraulic liquid and can be slow.   They are however the only really choice when it comes to doing the heavy lifting of heavy machinery.

Pneumatic Linear Actuators

Pneumatic actuators work in the same way Hudraulic Actuators work, in that they also require a pump to build in air pressure and hoses to connect to each actuator. They eve work in the same way in that they push against a piston inside the Actuator body to push the piston in one direction, and through a switching valve they switch the air supply to the other side of the piston head to make the actuator shaft go in the other direction.

The main problem with Pneumatic actuators actuators is that the working medium “air” is very compressible and spongy so that means as the force of the thing thr actuators are pushing or moving the Air gets compressed and this takes time for the actual movement to occur. In Other words there is some lag and this makes positional control very hard to come by.  

Piezoelectric Actuators

Piezo is a set of solid ceramic type material that respond to the electric charge by enlarging or contracting and create very small movements. Typical movements of a Piezoelectric actuator is in the range of 10% of the length of the Piezo Actuator to begin with.  So a 100mm long Piezo Actuator will only create 1mm of movement in general. 

therr are benefits to this movement however.  Piezo Actuators are highly controllable in terms of distance they move. So if you need to move the Piezo 0.3433mm of moment you can do that by controlling the voltage that’s supplied to the Piezo Stack.  That also provide a lot of force but are delicate.  They are also very high speed which makes them the perfect choice to be used in Fuel injectors for cars, where they are used to open and close cables hundreds of times per second.  They can also be made extremely small which makes them suitable for micro applications. 

Electric Linear Actuators

As its name suggests, electric linear actuators use electric energy to allow movements in a direct line. They operate by moving a piston back and forth according to electrical signals and are used mainly for movements like pulling, pushing, blocking, lifting, ejecting, clamping, or descending.

Linear Actuator
Linear actuators work with a motor that creates high-speed rotational movement along with a gearbox that slows down its impact. Consequently, this will raise the torque, which will turn into a lead screw, which causes the linear movement of a rotating shaft or drive nut. Shifting the link's polarity from the engine to the battery could make the engine rotate in the opposite direction.

 

Electric linear actuators are available in distinct strokes, which are accomplished by increasing or reducing the shaft's length. With various gears, different rates may also be attained. Broadly, the greater the rate of the screw, the less the drive. A switch over the primary actuator shaft on top and lower finish halt the twist as it reaches the end of its stroke or movement. Since the rotating reaches its ending, the switch cuts off power to your engine.

    The Capacity of Linear Actuators

    Performance metrics are measurable outputs that enable you to assess the quality of a specific item. Actuators are considered under many performance metrics. The most common ones are torque, speed, and endurance. Lately, energy efficiency can be regarded as significant. Other aspects that could be considered include quantity, mass, working requirements, etc.

    Electric Linear Actuator Force

    There are are 2 types of forces to consider in Electric Actuators.  Dynamic force - this is how much force the actuator can actually push and pull, and then there’s static force, this is how much force the Actuator can hold in one place.   

    Speed

    The speed of an actuator is dependent on a few things.  Firstly they are directly proportional to voltage, so a 24v actuator will go twice as fast as a 12v actuator, but also the gear ratio inside the actuator dictates the speed as well as the leadscrew pitch. but one thing to remember is that speed and force trade-off against each other in Electric Linear Actuators. So as speed increases the force must decrease and visa versa 

    Actuator Energy Performance

    Linear actuators convert rotational movement in electric motors to straight or linear push/pull movements. Linear actuators are best for all sorts of applications where lifting, pulling small to large force will be needed.

    Electric linear actuators are usually the preferred solution if you want a comfortable, secure, and clean motion with accurate precision and smooth movement control.  If you are interested in using electric linear actuators for your next project, Firgelli Automations can supply you with what you need.

    As industry leaders, Firgelli Automations carries the most extensive inventory of linear actuators for every application. You will find the perfect linear motion product and accessories tailored to your project.

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