Issues with modeling a tensegrity-membrane structure in MuJoCo #2666
Replies: 2 comments 7 replies
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To simplify the model, can you replace the cloth with a rigid box? If that is stable then we know the issue is indeed with the cloth |
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I will give it a try, really really thanks for your reply! |
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It will still fall, but what's different is it will not compeletely fall to the ground,it will bounce a several times before it's stable, maintaining a low pose close to the ground, but I think it's much better. 2025-06-05.201959.mp4 |
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Can you post this model |
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` ` |
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this one is after I replaced the membrane with the box, i managed to change the length of the tendons that link those bars, it seems bigger value of length could support the whole structure's balance, but i still don't know why it can not support itself when it is membrane on the top |
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Do you have an image of the real thing your are trying to model (if it exists)? It's difficult to understand what you are trying to achieve. Some comments just from looking at the XML:
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We are still in progress of building this structure in reality,but there is a small model in reality, I will show it below: actuation.2.mp4I used the red color to mark the pillars, the reasons why they have ball joints is because they have to move with the tendons to make the whole structure at a specified pose like above, as you can see the pillars still can not be stick tight to the box(which should be membrane) with the movement but it's much better, but I still want to change the box back to membrane if I'm able to, and I'm glad you could help setting the model,thanks. latest XML:
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Why can't the tendons be connected to the world? I don't think you need the pillars at all. I mean you need them in reality, but not in the model. |
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Intro
Hi!
I am a collage student who is using MuJoCo on modeling a tensegrity-membrane structure .
My setup
3.2.0
My question
Recently I‘ve been working on modeling a tensegrity-membrane structure in MuJoCo, the structure itself is able to balance in the reality. However, we want to add motion control to the structure, in that case, we need to build a model of it in MuJoCo for further research and analysis. the structure is composed of four bars and four tendons and a membrane on the top, the image of the structure is shown below:
As I said earlier, this structure has been proven to maintain static equilibrium in reality.The problem is that, after I build the structure with XML language in MuJoCo, it can not maintain static equilibrium,it will crash to the ground real quick, I don't know what has caused this situation, the parameters of the membrane is set in the plugin,the problem is shown as below:
Phenomenon.mp4
I used connect element in equality to bind the four corners of the membrane with the bars and tendons,I will share the file in the end and here is my guess to this problem:
The membrane does not seem to be stretched tight, so it does not provide the required tension to the bars，probably some of the setting is wrong in my file and I will be happy if you could point them out and give me some advice,thanks!
Minimal model and/or code that explain my question
If you encountered the issue in a complex model, please simplify it as much as possible (while still reproducing the issue).
Model:
minimal XML
Confirmations
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