Question 6DOF with servomotors for flight sim in VR

Thanks for your help.

I have a 3D Printer, and already one ball nut removed from the screw (a newb mistake few month ago). Do I have to remove white caps at top and bottom of my ball nut before ?

Thanks

No, you don't.

Ok thanks a lot. I just have to print a 16mm cylinder in 3d

Check @Hoddem actuator thread, he also posted the 3dprint file for the screw, I got it printed and it works like a charm.

yes but it's a 1605 nut, I have a 1610 !

OK

I had to re-assembly a 10mm pitch ball nut and I just printed a tube, it wont be 16mm OD though. That is the OD of the ball screw so you will have to subtract some amount for the ball bearings. This is the one I used, quick and dirty but it works. I removed the white dust seals in order to re-pack the ball nuts, then after I had the ball nut back on the screw I reinstalled the seals.

In order to re-assemble I got some sticky lithium grease and carefully loaded each ball in with a tweezers (36 of them I believe). I then inserted the tube into the ball nut and finally set the non threaded end of the ball screw inside the tube. from there I just rotated the ball nut onto the screw. the hardest part is getting all of the ball bearings in place and keeping them there before you install the tube.

Thanks to you, I printed this night a tool like @Hoddem and it worked !



I would like to test 3DOF before going to 6, is that kind of design stable ? do I have to block manually some DOF ?


THanks

I think you will need to block some, I'm going a similar route and I'm using different fix to the base in the back actuators than the front ones:

But I'm going to use 4 actuators.

This one is more like the one you want to build:

Hi guys,

I have finished my actuator design :




plate diameter is 160mm, ballscrew is sfu1610, SM is 750W, 2.4N.m, 3000rds/min, total stroke is 480mm.

@SeatTime @baykah @Hoddem and all others, what do you think of it ? do you have some advice for me before I keep going ? motors and ballscrew are already bought

Thanks

Just to be clear, my actuator design was for a 6DOF. The loads will be different for the 3DOF rigs shown above, requiring a different actuator design. You will require something similar to what @mariano68 shows in his photo above.

Oh, my rig will be 6 dof finally

Not a lot of help right there

here is the v2 :

'Motors and ballscrews already bought' Apart from recommending poly bushes, the design looks like my actuators, so I don't know what else to say ....

I think that is actually not a bad idea. Ball joints give you 3 angular degrees of freedom (of the 6 DOFs you need in total) in a single spot. And they are light and cheap. But they come with a very limited range of motion. Much less than a well designed U-joint! If you are concerned that the angular range of motion is going to be a limiting factor, then using (well designed!!!) U-joints on the top could potentially remove an unnecessary bottleneck from your range of motion.

None the less, I would first check in CAD if the range of motion is actually limited by the joints before going that route.

In my design I have used custom one-sided U-joints running on ball bearings on top AND bottom, but it required an additional axial bearing in the rod to reach 6DOFs. The result is a huge range of motion with absolutely zero backlash. But not everyone is going to want to go through such trouble unless there actually is a bottleneck that you need to remove.

Cheers