6 DOF Motion Platform

And now for something... a little bit different. You may remember that I have a pretty extensive background in both Aerospace and Mechanical engineering. For the last year and a half I pretty much shelved those skill sets to make room for a veritable deluge of new information in the field of Software Engineering whilst earning my Masters Degree. This November though, I ran across www.xsimulator.net  during a little browse-sesh around the ever-expanding VR marketplaces of the web. This community of enthusiasts and tinkerers builds up custom Software and Hardware for DIY motion simulators that result in some pretty amazing pieces of kit. I was... inspired.

Unable to hold back on this one, I cracked open the old mechanical design tool kit as soon as winter break hit and knocked together my own design for a high-speed, high-thrust, long-throw linear actuator based on the now commoditized 1605x500mm ball-screw assemblies being put to work in DIY CNC machines all over the world. Borrowing some high level design concepts and material selections from the guys over at xsimulator.net, I designed and prototyped fully self-contained actuator I have dubbed "Aurora" in honor of my cat. A choice driven mostly by the significant number of hours she spent curled up in my lap during the design process combined with my general lack of creativity in naming.

Over the next few weeks I cut parts from Acrylic and Aluminum extrusion on my CNC router (yay toys!), assembled, tweaked, redesigned, re-cut, re-assembled, and retweaked until I was content with the overall design. I have now landed on a very clean, modular design that is meeting or beating expectations in almost every respect.

Now I've started the next phase, writing a whole bunch of software to control the system! I'm writing everything in C# and exercising the .NETMF embedded system framework for control with all signals delivered via a CAN (Controller Area Network) bus which borrows its initial design from the automotive industry, and later expansion and refinement from the robotics industry at large.

Once the software is finished (haha... finished... good joke...) I'll be cranking out five more of these things to put together into a motion platform configuration known as a "Stewart Platform", very commonly used in large scale FAA motion simulators. Should be fun!

I'm still on the fence about whether I may try to productize and sell the design... so for now the covers stay on. But if I decide its just for fun I'll put up a more detailed build log and open source the design and software. Stay tuned for either a KickStarter or a data dump...

But without further ado, here's the Aurora Xtrusion-based Linear Actuator so far:

Excellent fixturing leads to excellent parts. Don't skimp :)

Now, make a lot of dust...

...then vacuum it up. Use a cyclone separator though... that shit'll wreck a vacuum in like 10 seconds.

After unfixturing. Man do I love my CNC machine... www.axiomprecision.com btw

Cutting some Aluminum extrusion to length on the CNC. A little slow, but +- .1 mm is hard to get any other way.

Remember what I said about solid fixturing? I meant it...

But the outcomes are hard to argue with. Some sexy ass cover panels.

So here's "the kit". This may end up being the way I sell these things, but there's nothing left to do from here but 1 epoxy joint and a bunch of screws... so its not too bad.

And the finished product, the Aurora XLA, prototype 1

Specs (for the technically inclined):

Length: 800 mm
Throw: 350 mm
Speed: 350 mm/sec
Thrust: ~650 N (testing to come)
Weight: 5.5 kg (12.0 lbs)
Peak Power: 360 W
Theoretical max resolution: .0025mm
Repeatability: .125 mm positional accuracy (so far... that may get even better with some tweaking)