News 6DOF stewart platform with linear actuators

Hi all,

I'm starting this new thread to document a new design and build of a diy 6 dof stewart platform (after several false starts over a period of nearly 25 years), hopefully I'll have the time now I am retired to get this one completed.

I'll be using linear actuators so I can get the range and power - looking at 1g with about a 150-200kg platform.
Not sure type of drive motor servo/stepper/dc , I can design for all types, just depends on cost/performance (would prefer servo - prob £300-400 a leg). Will probably be using a 2020 ballscrew to get the stiffness and speed. I did make a prototype 650mm stroke actuator using a 2020 ballscrew with a 20nm side mount 3 phase servo, this could throw a 55kg lead weight up and down full stroke as if it wasn't there !

Currently got a model in my office using small steppers and trapezoidal leadscrews (very noisy !) to model my control software.

Will be designing and building all my own hardware (I've finally got a major workshop !) will be using SimTools with Xsimulator plugins to run it (no brainer for those, at the price and performance it's not even worth thinking about making a program)

Apologies if my posting doesn't yet conform to forum rules, I'll learn as I go along and I hope someone will quietly point out anything wrong.

Follow on from last post - I've rejigged a program I wrote to calculate/visualize machine sizes, leg positions and forces for a linear stewart platform, will take several more days before I can package it a single small exe file but can post it as a zip file that has all the dependencies for now rather than using github etc if forum rules allow but it is about 24mb (forum moderators ?)

Looks like you have got everything covered and you are building a nice sim

Probably best to upload the program to github / cloud, and post a link to it.

What did you do before you retired?

Hi Gadget999,
I used to be a qualified senior electronics design engineer and computer programmer in my younger days.

Hi steveh, the actuators that you have that speed in inches second can go out and back.

Just created a github listing for my calculator - look for https://github.com/SteveH-awf/6dof-stewart-platform/tree/Calculator. Note, this is obviously a work in progress and just uses SI units for now.

Me too

Just a follow up on my build progress...

Slow progress last year due to persons/pets expiring, the cold weather this time of year doesn't help either.

Ended up using three phase 20 Nm servo drives (china) with 20 mm ballscrews and 10 mm pitch - total overkill, never even get warm. Updated my driver hardware several times, latest one uses individual custom pcbs's STM32F401 cpu's and usb hid interfaces for each leg (now very fast and smooth). Rebuilt the base and platform frames a few times but everything running pretty much ok (could do with bolting to the floor !) just have to tune the variables in simtools to get a decent flight (nasty kick in yaw). I've attached a few pics to show progress and when the weather warms up enough to stay in the workshop more than a few minutes at a time I'll post a video of it operating.