Problem with Suspension Simulation: Cable Not Showing Stretch Under Load #2273
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Hi @ValentinaGiannotti the cable cannot stretch, it's meant for situation where the tensile load is negligible compared to the other forces. If you have a cable in a tensile configuration, I would recommend using flexcomp instead. I have added an extensible 1D example last week https://github.com/google-deepmind/mujoco/blob/main/model/flex/pulley.xml (note that I haven't had the time to add bending and twist stiffness to this extensible cable yet) |
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Yes, exactly. Using the grid approach, the issue is that I cannot attach the first and last bodies of the cable to the cylinder. I tried using the weld command to link the bodies, but it doesn't seem to work as expected. Additionally, the FlexComp command does not allow me to create a site. |
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What is the issue with the weld? |
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When I use the weld to connect two bodies, I can make them move together, but not as a single well-defined entity. This happens because I can’t determine exactly where the connection between the two bodies takes place. I would like to use sites to precisely define the connection point, but this is not possible because I can’t define a site for flexcomp. As a result, I can’t accurately control the specific point where the cable and the cylinder are connected. |
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You can load and save the XML and the flexcomp will be expanded into bodies, to which you can add a site. Is this a feasible solution? |
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Thanks, it works |
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Intro
Hi!
I am a student at University of Federico II, I use MuJoCo for my research .
My setup
Mujoco 3.2.6
My question
Hi everyone,
I'm working on implementing a suspension system in MuJoCo to analyze the oscillations of an object hanging from a cable. I've modeled the cable as a composite object of type cable and added a constraint to attach the object to the cable. However, I'm encountering an issue: while the object remains suspended, suggesting that the cable stretches due to the weight, this deformation is not visually represented in the simulation.
I’ve tried tuning the equality solref parameters, but the object continues to float as if disconnected. Additionally, the heavier the object, the further it drifts away from the cable.
Minimal model and/or code that explain my question
Confirmations
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