Question Rotary 6DOF Design Help and Project

Hello All,

After seeing the amazing work here with the SilentChill, Peacemaker, etc. builds, I have been inspired to try and build a stewart themed rotary 6dof that could serve as the basis for some racing and flight sim fun.

I have tried to consume the abundant information available here. In addition, the details elsewhere like Fabi's blog, the "6 DOF Step by Step DIY Project, and the OpenScad sketch program with math details here: https://www.xarg.org/paper/inverse-kinematics-of-a-stewart-platform/. I am not claiming to have any understanding of the math, but the small tidbits I think I grasped from playing with the node.js application and openscad model seemed like they made me smarter.

Using Fusion360, I attempted to apply and duplicate the concepts from the above. The joints and motion in Fusion360 appear to allow for about 25 degrees in the pitch, yaw, and rolling with the below measurements.

Platform
The top platform has 20" (508mm) and 8.4" (214mm) wide sides. The bolts from the platform to attach to the rod ends are 3.93" (100mm) apart. The triangle the platform is based on circumscribes a circle with a radius of 10.6" (270mm).

Base
The base outer circle has a diameter of 5'2" (1575mm).
The circle that inscribes the large triangle has a radius of 20.66" (525mm).

Motors
The AASD 80ST motors have been modeled with 100:1 planetary gears. I went all in and bought the motors, gears, and Thanos controller. Each pair of motors are 35" (889mm) spaced apart from each other. The tips of the planetary gear shafts are about 16.4" (415mm) across from the closest motor.

Rod Ends
The LH and RH rod ends with bungs and misalignment spacers were modeled as close to something like this as possible:
https://www.rockwelloffroad.com/pro...eims-bungs-jam-nuts-and-spacers-2-lh-and-2-rh
In addition the Rod Ends on the bottom near the lever are about 1.75 inches (44.5mm) from the center of the balljoint to the center of the level. The top rod end tops are about 2.5" (63.5mm) from the center of the balljoint to the 8.4" side of the top platform.

Rods
The 1.5" tube is about 20" long making the total length with the rod ends about 23.5" (597mm) from center to center on the balljoints.

Levers
The length of the levers are 8.5" (216mm) long. The spacing between the planetary shaft and bolt center to center is 6.5" (165mm)



My fear is that this might come off as information overload, but I am really wanting to learn how these measurements could be modified for improvement while additionally having a good amount of detail for anyone else that may want to traverse down this path as well.

Thank you all again for the details and inspiration. I look forward to the opportunity to learn and share

JEM

Added a video to show the range of motion that fusion360 roughly models with the joints. Is 25 degrees enough motion or is more desired for a better experience?

Maybe get some ideas from here:



Check out his channel, he has many instruction videos about it...



He is also on my Discord servers if you want to ask questions.

Thanks Thanos! I have commented on his videos. He did a very nice job.

Hey JEM, sorry to dig up an old thread but I'm just starting out the design phase of my 6DOF platform and was very impressed by your Fusion 360 model. I started trying to do the same for my platform (similar to yours but with motors on the inside of the base plate facing out, like Kaufinators) but I was really struggling with how to do the joints and the multiple motors (I'm pretty new to F360!) Is there any chance you could share the design file so I can see how you've done the modelling?

Also, did you ever end up building the platform and if so how did it turn out and is there anything you would have done differently?

Thanks!