Mechanics and Construction > Mechanics and Construction

Linear Motors?

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Drab:
I was having a google search for robots using linear motors, and I only found a few examples of industrial/experimental robots. Indeed, the Wiki page on linear motors doesn't mention linear motors being used for robotics at all - only monorails and railguns.

So I thought I'd find some people who know about robotics. I thought that linear motors would be perfect for replicating human or animal motion, because it's straight out linear like a muscle, rather than converting rotary motion. Plus, if one simply pulls, then two on either side of an arm can act sequentially like how muscles work. Apparently, linear motors tend not to be powerful though, and I'm not sure why.

waltr:
Try searching for 'linear actuators'.

Drab:

--- Quote from: waltr on November 11, 2012, 11:13:46 AM ---Try searching for 'linear actuators'.

--- End quote ---

Well, a linear motor is a type of linear actuator, only it has linear motion to begin with rather than converting from rotary like other linear actuators. I'm looking for robots which use specifically what seem to be called linear motors, rather than the other types of linear actuator.

waltr:
One type of linear actuator is a motor turning a threaded shaft. A 'nut' on the threaded shaft rides in a linear guide (or housing) to push/pull. These can have considerable force.

Soeren:
Hi,

--- Quote from: Drab on November 11, 2012, 07:34:15 AM ---So I thought I'd find some people who know about robotics. I thought that linear motors would be perfect for replicating human or animal motion, because it's straight out linear like a muscle, rather than converting rotary motion. Plus, if one simply pulls, then two on either side of an arm can act sequentially like how muscles work. Apparently, linear motors tend not to be powerful though, and I'm not sure why.

--- End quote ---
Linear motors are in effect like ungeared conventional (rotational) motors - like if you cut a motor lenght-vise and ironed it flat and that's why they aren't very powerful.

The strength of linear motors is the extreme speed that can be generated, but they'd be hopeless in a robot, where torque is more important and contrary to what you may think, human muscles are very different.

If you want something that acts like human muscles, "air muscles" are the closest alternatives presently.