High angle & Displacement 6DOF

Running simulator build projects.
Please use the image gallery for your pictures, a short tutorial can be found here.
The first image in the first post will be shown in the project gallery.

High angle & Displacement 6DOF

Postby DoctorD » Fri 29. Aug 2014, 14:41

Hi again X-Simmers :)

Well, it looks like I've gotten the bug... ...again.
Haven't even finished my first simulator and I'm on to the next. This time a 6DOF with big ambitions:
300kg rated platform capacity
+/-35 degrees pitch roll and yaw
+/- 250mm heave, surge and sway (500mm total travel in each displacement axis)
...and FAST!!!

To do this I'm gonna need BIG motors and STRONG gearboxes.
After some pretty solid research and design (massive thanks to Thanos/TronicGR), my shopping list was as follows:
6x 1.5kW induction motors (1400-1800 RPM)
6x 2kW programmable VFD's
6x 400Nm (or greater) rated gearboxes at around 1:50-70 ratio (24-30 rpm at the output)
Big torque arms from the gearbox (I'm going for 300mm lever arms)

I've also adopted a design that allows for modification to the platform geometry and load characteristics. This means I can keep it light and have some really wild motion with just a VR setup, but also load it up somewhere in the vicinity of 800-900kg at the expense of some travel and angular displacement.

Thankfully the internet has been kind and I've managed to source most of the big gear at some pretty crazy prices (I REALLY love eBay and Aliexpress!).

So far I've used Autodesk Inventor and AutoCAD for geometrical design, whilst Fly-Elise's 'Motion Platform Designer' is great to determine just how much I can get away with power & torque wise whilst sticking to the design scope.

EDIT: Current design image and photo of progress




Here's a quick pic of the preliminary design...



Be well guys,
DoctorD
Attachments
Last edited by DoctorD on Sun 15. Feb 2015, 13:23, edited 9 times in total.
DoctorD
 
Posts: 96
Joined: Sat 8. Feb 2014, 01:53
Location: Brisbane, Australia
Has thanked: 22 times
Been thanked: 43 times

Re: High angle & Displacement 6DOF

Postby Riton » Fri 29. Aug 2014, 18:04

Big !!
User avatar
Riton
X-Sim Supporter
 
Posts: 291
Images: 70
Joined: Mon 7. May 2012, 16:05
Location: France
Has thanked: 1 time
Been thanked: 15 times

Re: High angle & Displacement 6DOF

Postby DoctorD » Tue 2. Sep 2014, 10:17

Getting excited as things start to arrive in the post...

6x 2Hp 3-Phase motors - Brand new surplus stock from eBay ($80 each)
...and yes, the output shafts are very long. But nothing an angle grinder can't fix ;)


6x 1.5kW single phase -> three phase VFD's (Delta brand) ($200 each)


6x 300W braking resistors to help slow the motors down for fast oscillations ($30 each)


The gearboxes are being made in China at the moment (60:1, 450Nm, dual output shaft) ($150 each)


I am also getting some custom pieces made in China:
6x Torque arms ($40 each)
- 304 Stainless steel
- Variable length (100mm, 150mm, 200mm and 250mm connection points)
- 25mm thick, 340mm long, 75mm wide
EDIT: Torque Arm thickness and width changed slightly (24mm and 72mm respectively)


12x High misalignment inserts ($4 each)
- 303 Stainless steel
- To go inside my upper M20 rod end bearings to allow for +/-40 degree rotation (needed to give the platform pitch & roll I want)


I've also got a ton of little bits n pieces arriving (electrical gear, fasteners/joints, etc.) all thanks to aliexpress. Can't recommend enough.

The next big thing I'm excited about is my 220Amp welder (Combo MIG, TIG, ARC). Should be in tomorrow...
Can't wait to put that 3 day welding course to some good use.
Last edited by DoctorD on Thu 11. Sep 2014, 17:42, edited 1 time in total.
DoctorD
 
Posts: 96
Joined: Sat 8. Feb 2014, 01:53
Location: Brisbane, Australia
Has thanked: 22 times
Been thanked: 43 times

Re: High angle & Displacement 6DOF

Postby DoctorD » Tue 2. Sep 2014, 10:58

I might also mention this little gift from the gods...

My Oculus Rift DK2 finally arrived!!!
DoctorD
 
Posts: 96
Joined: Sat 8. Feb 2014, 01:53
Location: Brisbane, Australia
Has thanked: 22 times
Been thanked: 43 times

Re: High angle & Displacement 6DOF

Postby Stevant1 » Thu 4. Sep 2014, 12:53

Hey Doc,

This all looks great. I'm going with triple monitors myself since I already have a chair setup, but the DK2 is on my list. I had a DK1 but the resolution was not working for me. I see they have made some great strides in the tracking and the resolution. Keep me posted as I might be following you with that concept.

Looking good, keep us posted!

Stevant
Stevant1
 
Posts: 45
Joined: Sun 31. Aug 2014, 19:48
Has thanked: 8 times
Been thanked: 26 times

Re: High angle & Displacement 6DOF

Postby Riton » Thu 4. Sep 2014, 13:15

why not use simple rings for ball joint spacers?
User avatar
Riton
X-Sim Supporter
 
Posts: 291
Images: 70
Joined: Mon 7. May 2012, 16:05
Location: France
Has thanked: 1 time
Been thanked: 15 times

Re: High angle & Displacement 6DOF

Postby DoctorD » Thu 4. Sep 2014, 14:49

Thanks for the feedback Riton,

I went with the contoured misalignment spacer to maintain as much material in the piece as possible. I'm pretty much mimicking the same design as used in the car manufacturing industry (just google "high misalignment bushings" and you'll get an eyefull of what's used commonly).

At $4 a piece it's pretty crazy not to go for something as robust as this. Especially when I might be throwing hundreds of kilos on the platform with nearly 80 degrees of rotation in pitch and roll (+/-40 degrees from the horizontal). I'm imagining some pretty 'healthy' forces at play when at full speed.

The best feature of these inserts is that I am able to maximise the amount of material in the sharp edge of the piece (directly adjacent to the flat/cylindrical section). This means there is maximum ability to restrain lateral forces reative to the rod end bearing central axis, and minimal chance of shear failure in the sharp flange.

Here's a picture of them at the manufacturer to see just how fine the edge needed to be at the flange. That kind of machining is certainly beyond my abilities :)
Attachments
Last edited by DoctorD on Mon 8. Sep 2014, 03:09, edited 1 time in total.
DoctorD
 
Posts: 96
Joined: Sat 8. Feb 2014, 01:53
Location: Brisbane, Australia
Has thanked: 22 times
Been thanked: 43 times

Re: High angle & Displacement 6DOF

Postby DoctorD » Thu 4. Sep 2014, 15:07

...the beauty of having the bushes made to within 0.1 of a millimetre means that I can acheive platform angles like the one shown below (whilst still having the mechanical ability to add a significant amount of other rotations and displacements to the platform whilst maintaning the 40 degree pitch depicted in the image).

DoctorD
 
Posts: 96
Joined: Sat 8. Feb 2014, 01:53
Location: Brisbane, Australia
Has thanked: 22 times
Been thanked: 43 times

Re: High angle & Displacement 6DOF

Postby Riton » Thu 4. Sep 2014, 16:48

ok, thank you, I did not know I'll get in France if I find.
apparently it is all done.
actually it is not very expensive.
very nice project!
I like the concept.
the motors supports are adjustable?
User avatar
Riton
X-Sim Supporter
 
Posts: 291
Images: 70
Joined: Mon 7. May 2012, 16:05
Location: France
Has thanked: 1 time
Been thanked: 15 times

Re: High angle & Displacement 6DOF

Postby Stevant1 » Thu 4. Sep 2014, 18:25

Hi Doc,

Here are the one's I am using with a similar flange. I agree with your thought process in regard to the amount of material at the end of the flange for strength, yet thin enough towards the ball for clearance and maximum angle.
Attachments
Heim Joint.jpg
Heim Joint.jpg (4.45 KiB) Viewed 17315 times
Stevant1
 
Posts: 45
Joined: Sun 31. Aug 2014, 19:48
Has thanked: 8 times
Been thanked: 26 times

Next

Return to Motion simulator Projects in progress

Who is online

Users browsing this forum: No registered users and 3 guests