Spherical joint moves like spring

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Isaac Sim Version

[V] 4.5.0
4.2.0
4.1.0
4.0.0
4.5.0
2023.1.1
2023.1.0-hotfix.1
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[V] Ubuntu 22.04
Ubuntu 20.04
Windows 11
Windows 10
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GPU Information

  • Model: RTX4070ti super
  • Driver Version: 550.144.03

Topic Description

Detailed Description

I made a wire for simulate anti-sway crane and control it reingforcement learning.
So, I using SphericalJoint and capsule to make wire, but the joint moves like spring when box moving fast

image
image1022×401 128 KB

I connect capsule and spherical joint like that to make soft wire. I set like that.
capsule mass => 0.01
Cube => 1
joint damping and stiffness => 1000

but like video joint act like spring. How can I solve it?

Additional Information

What I’ve Tried

I try change joint damping and stiffness but they act like same.

How can i simulate rope for antisway crane simulation
3

Hi @herryjang, thank you for your question and very interesting setup. Can you please check out this example I put up for making revolute joints with passive stiffness/damping? Wire and Rope's simulation in Isaac Sim4.5 or 4.2 - #5 by michalin Let me know if that is what you are looking for. Basically, it is better to use a D6 joint rather than a spherical joint as Drive is only supported on D6.

Michael

4

To answer a question on accuracy of the simulated rope from here: How can i simulate rope for antisway crane simulation
You have multiple knobs you can tune here:

  1. Number of rope segments
  2. Segment weight or inertia
  3. Joint damping

It may be a matter of tuning those to get to the most realistic representation in your case.

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