Ghostpilots Aluminium Delta Throttle build-log

[Ghostpilot]

When one lower pivot assembly was done it wasn't so hard to finish and mount the remaining two.

[Ghostpilot]

It turned out that my idea of how to make the upper platform (Edit: Not the same as a Stewart platform, I have learned. All other instances where that name was used incorrectly has been changed to just "upper platform. Thanks Anrion for pointing that out.), was not so thought through. It's more complicated than it needs to be. I wanted the same tapering connection post for the swivel ball joints, on the upper platform as on the pivot arms. The taper chamfer is there to ensure that the rod end can swivel freely on its ball hinge without hitting the connecting point on the platform or pivot arms. When I choose to make the upper platform in a concave triangular shape, I on the same time made life difficult for me as I initially wanted the upper platform to be machined in one piece including the tapering posts. A concave triangular shape has absolutely no perpendicular flat faces for the part to rest on if I planned to clamp it down in the milling machine to machine the tapering posts directly on the platform piece. So to save me unnecessary headache I "reused" the connecting bar from the pivot arms and added two countersunk screw holes that goes through the cylinder on its radius axis.


I need to know at what diameter (measured from the center of the platform) the arm connection is at, or better yet, design it so the connection happens at a set diameter. As I was abandoning the solid piece upper platform for a simpler version with connecting bars screwed to the outer edges of the platform, I needed to make sure that the bars were parallel to the platform surface and tangential to the theoretical circle that touches the spots where the three arm connections needs to be. Therefore I used the bars unaltered with a full cylindrical shape and made a matching puzzle piece shape for it to sit in with two screws fixating it in its cradle. The holes in this picture are untapped, because I tapped those holes by letting a tap screw through the already tapped holes in the bar to make the resulting thread be continuous through both the bar and the platform. The bars were then screwed down with stainless M4 torx-headed screws and locktite.


Since I had already made one over-complicated swiveling Z-spring anchor with a thrust-bearing on the base, it was easy to make a similar one on the platform.



Now most mechanical parts are machined. A few minor adjustments left to do before I can do a final assembly. I need to add tapped holes for set screws in the torsion spring anchors on the base. I also decided to bead blast all aluminium parts to make them less reflective and shiny. As you see in the pictures most of the parts are bead blasted already. But I was foolish enough to mount the bearings in the bearing blocks before I had time to bead blast them. I don't want to get blasting sand inside the bearings, so I need to figure something out regarding that. I also need to start thinking/worrying about the electronics. I have neglected the electronic part up until now. I have the hall sensors I ordered as free samples from AMS, but I haven't made any pcb for them yet, nor any holder setting the size of the pcb. So there are much left to do before I can test fly anything with my delta throttle. I saw that I have a few duplicates or slightly damaged "spare" parts left over from this build. It would be a waste to just throw them so I might finish the abandoned actobotics sized base and make it mechanically functional even though it's not going to be that pleasing to the eye as this one.

[aniron]

Your build is looking sweeter with every update.

I do believe "Stewart platform" implies the geometry below, with six independent actuators giving 6dof as opposed to the 3-actuator-3dof of the delta platform we are using.

[Ghostpilot]

I stand corrected. A Delta Throttle does not have six independent actuators. It was a nice complicated term to use though. Lets call it upper platform from now on then.

[Cybertraxs]

Nice work Ghostpilot!!!!

I've had some life issues to deal with so my throttle has been on hold... wish I was able to mill out those parts!!! They look great!!

[Ghostpilot]

Nice work Ghostpilot!!!!
I've had some life issues to deal with so my throttle has been on hold... wish I was able to mill out those parts!!! They look great!!

I hope you can sort out those life issues. As for the parts to my Delta Throttle, I will publish all CAD files when I have verified everything works and fits as intended.
Its not a secret, nor can it be one either as it is based on the initial free plans, but I wan't to test if my changes were for the better or just complicating things for no reason before I pass them on.

[Ghostpilot]

First time full assembly. It's beautiful even though I made some mistakes here and there (I won't tell you where the flaws are). One thing I noticed is that the "home position" is not a point in space (as in theory) but a small area where the upper platform returns to at random places when released. That small area is indeed small so if that is going to have any effect on accuracy, only time will tell. Perhaps those springs I ordered from fjadrar.se is slightly weaker than those you guys use overseas. No matter, the mechanical movement seems to be working. Those IGUS.de rod ends perform well and the motion feels smooth and unhindered.


More beauty shots. Placed on the scratched workshop floor to stand out even more.


I wonder if my low profile bearing blocks restricts downward pivot movement of the pivot arms too much? How low do they really need to be able to pivot?

[aniron]

Really sweet!

Have you considered how you will route cables from the handle/upper platform down to the electronics?
I'm assuming you, like me, will want a decent amount of buttons and hats available for use on your delta throttle.

I've been gutting an old ambidextrous joystick to use as a grip for my delta once I get it working.

[Ghostpilot]

Have you considered how you will route cables from the handle/upper platform down to the electronics?

I was planning to have them bundled together and hanging "free" from a chimney shaped support. I felt that the cables would kink and break if I guided them too much, considering the upper platform moves in three axis.

I've been gutting an old ambidextrous joystick to use as a grip for my delta once I get it working.

I am still somewhat in love with the idea of something like a leather wrapped gearshift knob, but more almond shaped rather than round. But how I am planning to add buttons and thumb stick to such a handle, has gone without a single thought up until now.

[jeruw]

Looks great! I like the finish you got on your parts as well. I may end up making a small part tumbler to see how that works for me when I start making more stuff.

I'll be digging back into my builds soon. I've been busy building my own CNC for home and am just about finished with it.

What machine did you use for making your parts, and how do you go about doing the multiple setups (for machining both sides of your pivot arms? I haven't experimented with that yet as the machines I've been using are pretty basic and I'm very new to all this. I'm also curious how you did your pivot arm shafts. Was that done on a CNC lathe?