MuJoCo Cable model not working

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Ita10
Posts: 3
Joined: 08 Mar 2024, 11:11

MuJoCo Cable model not working

Post by Ita10 »

Hello everyone, at the following link you can find my attempt to simulate the grasping of a deformable cable with a manipulator.

https://we.tl/t-8tnUIW4Hwf

I am using the MuJoCo engine, as suggested by coppeliasim scene. I have taken the cable model from the scene "ropeTest.ttt". I have changed only cylinders size (they are longer and with a larger diameter) in order to be easily graspable, masses are low (all cylinders are 0.0001 kg), and inertia values are high to make it more stable (1.0 along x,y and z).

I have tried different configurations (high/low masses, high/low inertia values, longer/shorter cylinders) but there's a problem when I move the robot and the object is grasped (attaching parent function has been used). When moves are short, the simulation is quite stable, but when moves are longer and along the orthogonal direction of the cable, the elements of the model begin to move fast and uncontrolled.

How can I solve it?

coppelia
Site Admin
Posts: 10375
Joined: 14 Dec 2012, 00:25

Re: MuJoCo Cable model not working

Post by coppelia »

Hello,

can you give a link to the scene file?

Cheers

Ita10
Posts: 3
Joined: 08 Mar 2024, 11:11

Re: MuJoCo Cable model not working

Post by Ita10 »

Hello,
I'm sorry, but I can't provide the scene file, since it contains custom implementation of our software.
Nevertheless, what it is inside the scene is exactly the result that you can get when you apply the previously described parameters into the cable in the scene 'ropeTest.ttt'. I have used that cable as starting implementation, but It cannot be grabbed. The best result I have obtained is the simulation in the shared video, when the cable has been attached to the gripper as parent-child association.
Has anyone one of you ever tried to grab a cable like that in CoppeliaSim?
Thank you for your reply?

coppelia
Site Admin
Posts: 10375
Joined: 14 Dec 2012, 00:25

Re: MuJoCo Cable model not working

Post by coppelia »

What happens if you use a different engine for the same scene? is it similar, worse, or better?

Cheers

Ita10
Posts: 3
Joined: 08 Mar 2024, 11:11

Re: MuJoCo Cable model not working

Post by Ita10 »

Hello,
It does not change anything. Moreover, MuJoCo engine is the one engine advised for ropes test.

Since weTransfer link is changed, I'll attach it again to this message.
https://we.tl/t-ccV4okVGFb

Thank you for your support.

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