Hi,

Just want to drop in and present you my 6DOF stewart platform using AC motors and VFD inverters:

http://motionsim.blogspot.com/ ... sim3-using-beta-6dof.html

I use LFS and the new 6DOF plugin for x-sim3!!


Thanks!
Thanos

well ur a bad driver

The IRC channel for LFS saw the video. It seems fairly dangerous, but that's just cause the frame looks very small. I have no doubt that it works though.

How much have you put into the materials for it?

Quote from Hahmo :

well ur a bad driver

That's not very useful or relevant to the thread.

Hi dawesdust_12,

Its not dangerous if you take some precautions. Worst case scenario is if one of the position sensors breaks down, the motor might start rotating continuously. It happened once, as the camera guy was walking by the motors and stepped on the cable of the sensor while it was working and pulled it of its connection, but did not affect anything else of break anything on the platform. The other 5 motors kept the platform in place...

The cost of materials is six times the following:
AC motor 0.75hp = $112
Gearhead 60:1 = $241
AC VFD drive 1HP = $224
Magnetic sensorless position encoder= $15
Supports, rod, arm = $55-$70

So much inexpensive to built it yourself instead of getting ready built 6DOF platforms (Ckas for example)

Best Regards,
Thanos

I find these motion platforms very interessting.

Quote from tronicgr :

Its not dangerous if you take some precautions. Worst case scenario is if one of the position sensors breaks down, the motor might start rotating continuously.

Do you have an emergency shutdown/panic switch in the cockpit? Or even better a second one outside too. That would seem useful.

Of course there is an emergency switch that kills the signals to all motors within 1/1000 of a second.

But even if everything goes wrong there is no big danger. We had a situation that because of longer arms we used for testing, the cockpit positioned itself in a angle larger that 45 degrees and the two front motor arms were locked in place as they were parallel to the rods. I would expect something catastrophic to happen but no. The motors were just kept whining trying to reach the position. Didn't overheated, didn't shutdown the inverters from overload with fault message, didn't even dropped the mains fuses...!!!

If the same happened with DC motors you would be lucky not to burn the h-bridges or the motor coil!!!

Best Regards,
Thanos