Inverted Stewart Platform from three Makelangelos

inverted stewart platform, side view

I’ve been trying the last few days to rebuild my old Stewart/Gough platform. I was stuck with the problem of interfacing parts – attaching two parts that don’t normally want go together. Three days ago I was having a brainstorming session with new VHS member Freddie and he mentioned that they’d been built upside down with cables. It was like lightning striking – I suddenly remembered RoboCrane and I almost screamed “Why didn’t I think of that earlier?!”

The model I’ve come up with is a 3-3 platform. That means the strings at the base meet at three points and the strings at the end effector meet at three points. There are also 3-6 and 6-6 platforms.

inverted stewart platform end effector

To build this I used a few pieces of laser-cut acrylic and three Makelangelo kits.

inverted stewart platform motor mounts, alternate view

This is very similar to the method Antonio used to mount his Makelangelo – keep all the motors in one place and run extra long strings.

inverted stewart platform motor mounts

The rest is software, which I’m writing at this very moment. If I had an extra RAMPS board I could run this machine far more efficiently. As it is I’m maxing out the USB connections on my laptop.

inverted stewart platform connections

When I release the code the laser cutting templates will come with it so you can make your own. I love that I can add this to my store without having to stock a single extra piece of electronic equipment.

Now let’s see if I can get this thing running by Sunday for the monthly meeting of the Vancouver Robotics Club. Wish me luck!

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