I spent quite some time (almost) perfectly aligning my reaction wheels. Vibrations at multiple thousands of RPMs are no joke. Then again, such speeds are typically unnecessary once the cube has settled into its equilibrium position. ReM-RC on YouTube has built a similar cube which uses 3D-printed wheels with steel bolts in the circumference [1].
My wheels are oversized when you just consider the balancing application, but I want to add jump-up functionality later, and the wheels need significant inertia (and also need to run at significant speeds) to accomplish that.
Cool. The 3d printed wheels presumably would have some dampening properties vs. the steel ones. You can also attempt to balance them at speed (moving/adding/removing the weights) to try and minimize vibrations like you do with motorcycle or car wheels (I guess there's multiple modes though).
This is definitely something I’m thinking about doing! I would ideally like to keep the reaction wheels visible though. Putting LEDs inside the wheels for a persistence of vision effect might be cool.
That’s an interesting idea. I have no good answer to your question, but something like a dodecahedron comes to mind, as a ‘trade-off’ between a cube and a sphere.
If the edges were all made as small arcs with extra actuators to rotate them either flat along the surface or outwards to form something that can roll. Might need to do the same for diagonals to get it to roll smoothly?
I like the actuated edges idea. I'm imagining it using an edge to hook the top of a step, pull itself half way up with edge actuation, and then building up momentum and slamming a brake to kick itself onto the stair.
Some things certainly can be modelled, but for others it is easier to simply try. For example, will applying a positive current to the motor make it spin in the clockwise or counterclockwise direction? It really depends on the behaviour and configuration of the motor controller, and in this case it was easier for me to just try.
The trick is to do these tests at a sufficiently low level, because that’s usually where these issues are, in my experience.
