6 DOF Cube

[schraubedrin]

Somebody told me about a special form of movement platform that's a spin on the traditional Stewart platform:
Instead of positioning the actuators in a flat triangle, they are mounted in pairs on the surfaces of a cube.

As there are still six actuators, it's still able to move and rotate in any direction:

 

The actuators aren't mounted in universal joints to simplify the construction and make it more compact.
To get the necessary two degrees of freedom to rotation, the actuator can pivot in one direction and rotate around the actuator axis:

The most time went into finding good positioning for the connection points so that there is enough movement range without internal collisions.
This proved to be the hardest part because their positions are quite closely connected, so there isn't as much freedom in construction as you'd expect.

In the end i found a nice balance of movement range and not too many collisions.
Not making it a cube would have improved the movement a lot, but i liked this design much more

I made one face of each the actuator side and the moved side as see-through as possible.

 

 

Edited November 16, 2024 by schraubedrin

[Maaboo the Witch]

Weeeeeeeiiird.

[tseary]

Thank you for sharing this. I had never heard of this mechanism before! It really looks like sci-fi tech; Borg or something...

I wonder how this compares to the Stewart platform in force and range of motion. I'm guessing the Stewart platform has some kind of advantage considering how common it is. Although I can imagine this cube being applied in a modular robot.

[schraubedrin]

1 hour ago, Maaboo the Witch said:

Weeeeeeeiiird

Exactly my thoughts on hearing of this concept for the first time
That's why i had to build it.

1 hour ago, tseary said:

Thank you for sharing this. I had never heard of this mechanism before!

My pleasure, i'm glad other people find this as fascinating as me

1 hour ago, tseary said:

how this compares to the Stewart platform 

This version has the advantage of a similar range of motion in every direction.
I'd guess the traditional platform is stiffer, depending on the design.
And i'm pretty sure the reverse kinematics are more complicated if the joints are not on a plane