Question Is this will work 3 dof 4 actuactor???

My desain is 4 actuactor on corner, but i dont upsidedown the actuactor. Like on the picture, its will work or will get trouble?? Base of actuactor is fix welded on the base rig, on the stroke of actuactor with rod end(ball end) to the up rig..
Or i need to make it upsidedown??

Need to add some joints. When the actuators move, the angle of the upper frame will change, which will require changing the installation angles of the actuators (this requires joints at the bottom) or changing the linear dimensions of the upper frame (which is impossible in this design)

If pur botem joint the rig will falldown, because on the up already with rod end ball joint sir

Yes, you're right, but that doesn't change what I wrote.

I am considering a similar design.

I assume the top joint (not visible in the photo) is a standard heim joint (spherical rod end) with its axis oriented front-to-back.
- Roll is largely unaffected (the joint pivots freely side-to-side).
- Pitch is severely restricted to ≈ ±10–15° (exact limit depends on the specific heim model).
- Exceeding this range causes binding, accelerated wear, or catastrophic failure (spherical race cracks or rod end pulls out).

If the top joint is a ball-in-socket design (e.g., trailer-hitch style), angular limits become effectively irrelevant (±45°+ easily achievable).
- A trailer hitch ball + coupler would work mechanically but is sloppy and noisy.
- Better solution: Machine a precision socket and pair it with a PTFE (Teflon) liner sheet (2–3 mm thick, 2–3 inches diameter).

Real-world precedent: My Hobie 16 mast used exactly this—stainless ball in an aluminum receiver, with a flexible PTFE disc between ball and mast base no grease required.

Bottom line: Ditch the heim. Use a trailer ball (or machined equivalent) + custom PTFE-lined socket—cheap, durable, silent, and gives full SFX-100 motion without joint-angle worries.

EDIT: Just occurred to me that machine HDPE as the load bearing surface backed by an aluminum plate is a better solution.
.

This is not a viable design you would need to have the actuator's fixed solidly to the frame and free standing on the floor without a base
Otherwise the frame/actuator's are liable to break
you would either want 3 actuator's with a rotational stopper but ability to move up and down or 6 actuator's to make a Stewart platform with both top and bottom ball joints for each type

I already tesed, im stand alone motion, like try, roll only, or pitch only or heave only, its work normal without problem, but, when i combine like litle bit roll+pitch+heave, its will get problem like actuctor bending.

I already tesed, im stand alone motion, like try, roll only, or pitch only or heave only, its work normal without problem, but, when i combine like litle bit roll+pitch+heave, its will get problem like actuctor bending.

I follow the desine like this, the deferent is only my actuctor not upsidedown. On this picture ctuactor upsidedown sir. Its deferent efec, because my actuctor if free rotary, nothing stopper rotary for the rod sir.?? I already tesed, im stand alone motion, like try, roll only, or pitch only or heave only, its work normal without problem, but, when i combine like litle bit roll+pitch+heave, its will get problem like actuctor bending.

It's feasible it will work if tuned that way but always running a risk of actuator's working against each other the beauty of 3 or 6 axis is there is no chance of bending
any movement on any actuator at any time will be fine

So i need to make upsidedown the actuactor?? And give him free?? Like this desain?? But i dont know this actuactor have rotation stopper or no, because my actuactor without rotation stopper.

yes that design has no base mounting so rotation isnt needed as the actuators are fixed at the top
the floor side just has the flexibile joints so as not to drag on the floor

Okk, but my actuctor without stoper like sfx100, so thats means you can rotation the rod by hand manualy, when the sfx100 cannot becaus e insede the desin with stopper

the rod rotation is not the issue its the rotation of the whole seat base which would be the problem

So we no need to care about rod rotation?? Just need make it upside down right mate??

Now i test like this, but the rig like will falldown must be make fix on the tor right?

yes that will not work like that the bolts will rotate

you really really should just go with 3 actuators i promise that is the best thing much better than 4

what joint is on this? is it a rose joint? or roll pin?

Why sir?? But i like the desain 4 actuactor sir, more balance