dutchkiwifruit

6 ms·

1.
by dutchkiwifruit 3y ago
That would be fine too but I dislike the idea for aesthetic reasons.
2.
by dutchkiwifruit 3y ago
Bobrow’s research mentions a set of equations that can be used to derive the controller gains based on a set of dynamics-related parameters of the cube (like inertia, mass), but the results were unsatisfactory, so I tuned the gains by hand.
3.
by dutchkiwifruit 3y ago
Thank you!
4.
by dutchkiwifruit 3y ago
Fusion 360 calculates things like moments of inertia and weight, and this was very helpful since the controller requires these parameters to convert control inputs to torques, for example. I still had to tune the controller gains, of course
5.
by dutchkiwifruit 3y ago
Most of the dynamics and kinematics involved are thoroughly discussed in the research work that has been published by the authors of the original Cubli! For example: https://ethz.ch/content/dam/ethz/special-in
6.
by dutchkiwifruit 3y ago
Agreed. If only to enable others to reproduce and improve on the work.
7.
by dutchkiwifruit 3y ago
I've considered various concepts for the brake design and think the way forward is to use friction brakes. The original Cubli uses bicycle brake pads, but this has its disadvantages. I'm thinking about using a (possibly bidrection
8.
by dutchkiwifruit 3y ago
My envisioned solution to this - very real! - danger is to attach some very thin round sheets of steel to the wheels such that you can’t stick your fingers in them.
9.
by dutchkiwifruit 3y ago
That would be cool. I thought about balancing one cube on top of another balancing cube, but sadly I’ve only got one.
10.
by dutchkiwifruit 3y ago
The house always wins!
11.
by dutchkiwifruit 3y ago
Thank you! The weight of each wheel is approximately 220 g, whereas the total weight of the cube including wheels is 1700 g.
12.
by dutchkiwifruit 3y ago
I’m not sure! You could probably at least double the rib length if the wheels are scaled accordingly. I can however answer the opposite “how small” question to some extent by linking to this really cool project: https://youtu.be&
13.
by dutchkiwifruit 3y ago
No worries: https://youtu.be/woCdjbsjbPg
14.
by dutchkiwifruit 3y ago
Yes, the reaction wheels normally rotate very slowly.
15.
by dutchkiwifruit 3y ago
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
16.
by dutchkiwifruit 3y ago
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.
17.
by dutchkiwifruit 3y ago
I didn’t know about this, but it’s great! It makes me wonder whether I should come up with some kind of funny enclosure for my cube now, haha.
18.
by dutchkiwifruit 3y ago
Your comment makes me smile. Thank you! :)
19.
by dutchkiwifruit 3y ago
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.
20.
by dutchkiwifruit 3y ago
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
21.
I designed a cube that balances itself on a corner(willempennings.nl)
2460 points by dutchkiwifruit 3y ago|377 comments