HELP......Linear actuator

[bigmig95]

I've been tasked with trying to find a linear actuator of some kind to run a piston test rig, the rig must be capable of around 20-30N force with a stroke of up to 90mm. I've been looking looking at the speeds of those available and most are coming up short to my requirement which ideally be 20m/s !!!, I would have thought these actuation speeds are unatainable, however I'm no expert hence my thread, anyone any recommendations or assistance? Max speeds available on the market might give me some ideas as to which form of actuator I need to be looking at.

 

[amptramp]

What does your expected motion profile look like, i.e., accel-decel rates, jerk, etc.

So far the technology at the link below has the fastest velocity (11 m/sec) for a mechanical system that I have found.

http://www.nasatech.com/motion/features/feat2_0210.html

Maybe an over-sized hydraulic cylinder with a servo/proportional valve in closed loop.

Obviously, the motion profile is significant as mechanical systems will "jerk" themselves apart at inappropriate accel-decel rates.

 

[itsmoked]

Use a variable speed motor and a bell-crank.

Keith Cress
kcress -

http://www.flaminsystems.com

 

[jraef]

Do you need a 20m/s (about 44 MPH) actuating speed or a 20m/s² acceleration rate? At 20m/s you are going to get to the end of your 90mm stroke in 4.5ms (give or take a few ms based on the accel rate). At that speed whatever you have that will stop the travel at the end of your 4" stroke will be getting hammered!


"If I had eight hours to chop down a tree, I'd spend six sharpening my axe." -- Abraham Lincoln
For the best use of Eng-Tips, please click here -> faq731-376

 

[jpolson]

I have never seen a linear actuator run that fast. I am assuming that you need to start from zero speed and then stop the rig at the end of the 90mm. That is pretty darn snappy...

I would look at pneumatic cylinders with a rubber/polymer bump stop on each end. If it needs to decelerate itself you can bleed air into the other side of the piston as an air brake.


Joel Olson

 

[FACS]

Pneumatics won't last long.

Use a motor and put on an eccentric.



Charlie

http://www.facsco.com

 

[motion99]

Take a look at these actuators:

http://www.intellidrives.com/thrust-series-p-60.html

They meet your stroke and force requirements, max speed
~ 6 m/sec.

For 20 m/sec speed the only choice is an air bearing actuator, from bearing stand-point, hovewer motor type should be considered as well, probably voice coil type motor