When selecting an actuator for your product prototype or other application, there are a number of things to take into consideration. Force, stroke, speed, leverage, cost, volumes, availability and a manufacturer’s reputation, just to name a few. In this article, we’re going to walk you through these considerations and help you understand how to make sense of the actuator selection process.
What is an electric linear actuator?
An electric linear actuator is a device that drives motion in a straight line using either a rod that extends from the device, or a sliding block that travels along a track. They are powered by an external source and depending on model, can be commanded from a variety of inputs, including DC voltages (forward or reverse polarity), PWM signals, 4-20mA current loops, RC servo control interfaces, and stepper motor drive signals and more.
Electric linear actuators are used across dozens of industries and thousands of products that you use everyday. Aerospace, medical, robotics, automotive and culinary just to name a few. They’re in nearly every product you use that requires a motion element. With more and more products requiring some level of automation, they continue to increase in popularity. Keep reading to learn more about how to choose a linear actuator for your application.
Step 1: Determine the travel distance required
How far does the actuator need to move? This is the first thing to consider when choosing an actuator. No matter what other variables you’re considering, the actuator you bring in for your project needs to have enough travel to get the job done.
The distance that an actuator travels is called stroke length. The stroke length listed for a given product is the maximum distance that it can travel. For example, we offer actuators with stroke lengths as low as 10mm and as high as 300mm. By searching through our large selection of actuators, you’ll likely find one that meets your needs.
Step 2: Determine the force required
What is the weight of the object to be moved at the lifting point. This information will help you determine which actuator will be best suited for the job. If needed, you can increase force by adding more actuators. If you need a level of force that is not offered in the device that you want to use, you can mount more that one actuator to the project to achieve the required pushing force.
Remember to take into account the mounting angle. For example, if you’re lifting a hatch that is hinged on one side, you will likely not be lifting it from the outer edge. If the weight of the hatch is 10lbs at the outer edge, and you’re lifting it 6” in from that, the force required will be greater and you will need to determine the force required to lift from that specific point.
Step 3: Determine required speed
How fast does the actuator need to move to achieve your desired end result? We chose to make this the 3rd step as speed is typically a secondary consideration behind force and stroke. Additionally, force and speed are a tradeoff. When you increase one, the other decreases. The speed at which an electric actuator travels is subject to change based on the load.
We offer three numbers for speed on our datasheets: unloaded travel speed, peak efficiency point and peak power point.
There are a number of ways that you can increase the speed of your actuators including using pulleys, levers or multiple actuators.
Can actuator speed be adjusted?
Yes, it is possible to adust the speed of linear actuators. While that’s beyond the scope of this article, we have produced some past content about how to adjust linear actuator speed.
Step 4: Choose an actuator model
Now that you’ve worked out the specifications of your project, you’re ready to choose an actuator. While rod actuators are common in many applications, you might want to consider a track actuator for projects that require the movement of heavy loads or where a side-load is present.
You will need to consider how much physical space you have to mount the actuator. We have a number is smaller models available to accommodate tighter mounting spaces including the PQ12 and P8 lines.
Once you choose an actuator, you’re going to need to sort out how to control it. Depending on the product you’ve chosen, you may have several different input options. Our L12 line has the largest number of input options. That said, all of our DC actuators come in a -P series, allowing them to be used with our linear actuator control (LAC) board which gives you more control options including USB, RC Servo control, 1 kHz PWM, 0-3.3V and 4-10mA.
As you can see, when you choose Actuonix to drive the linear motion aspect of your product, you’re giving yourself access to the widest range of micro linear motion products available. Head over to our store to check out our full line of micro actuators.