Electromagnetic Actuator Mimics Muscle

Most electromagnetic actuators are rotating motors, or some variation on the theme, like servos. However, it’s possible to do linear actuation with electomagnetics, too. [Adrian Perez] demonstrates this with Linette, his design of a linear actuator that he was inspired to build by the structure of our own muscles.

The design uses a coil of copper wire in a 3D-printed plastic housing, surrounded by a claw full of strong magnets. When the coil is activated, the magnets are pulled towards the coil. When the coil is not energized, the magnets fall away. [Adrian] demonstrates the actuator under the control of an Arduino, which switches power to the coil to move it up and down.

He also notes that the design is similar solenoids and voice coil style actuators, though unlike most his uses discrete magnets rather than a single monolithic magnet. It’s possible to get more capacity out of the Linette design through stacking. You can parallelize the actuators to get more pulling force, with neighboring coils sharing the same magnets. Alternatively, you can stack them in series to get longer stroke lengths.

[Adrian] hasn’t put the design to a practical application yet, but we could see multiple uses for robotics or small machines. We’ve seen some other neat DIY magnetic actuators before, too. Video after the break.

Flexure PCB Actuators Made Before Your Very Eyes

When we see something from [Carl Bugeja], we expect to see flexible PCBs and magnets being pushed to do unexpected things. His latest video in which he designs a set of PCB actuators using flexure joints certainly doesn’t fail to please.

His intent is to create a simple actuator in which a magnet is placed over a coil, and moves upward within the confines of he flexure which surrounds it. And rather than try individual designs one after the other he’s created a huge all-in-one test array of different flexure actuators, each having a slightly different design and construction to whichever one is next to it. There are plenty of magnet flips as he tests them, and using this approach he’s quickly able to eliminate the designs which work less well.

To give an idea how these actuators might be best used, he tried them in a few applications. Their lifting force is relatively tiny, but he found them possibly suitable for a haptic feedback device. Of particular interest is that as the structure is a PCB it’s relatively straightforward to run a line to the magnet and turn it into a touch sensor. The idea of an all in one sensor and haptic feedback component is rather appealing, we think.

If you’ve not seen Carl’s work before, we’ve encountered him many times over the years.

Continue reading “Flexure PCB Actuators Made Before Your Very Eyes”

DIY Magnetic Actuator, Illustrated And Demonstrated

Electromagnetic actuators exert small amounts of force, but are simple and definitely have their niche. [SeanHodgins] took a design that’s common in flip-dot displays as well as the lightweight RC aircraft world and decided to make his own version. He does a good job of explaining and demonstrating the basic principles behind how one of these actuators works, although the “robotic” application claimed is less clear.

It’s a small, 3D printed lever with an embedded magnet that flips one way or another depending on the direction of current flowing through a nearby coil. Actuators of this design are capable of fast response and have no moving parts beyond the lever itself, meaning that they can be made very small. He has details on an imgur gallery as well as a video, embedded below.

Continue reading “DIY Magnetic Actuator, Illustrated And Demonstrated”