How to improve grasping in a very simple scenario?

[HoangGiang93]

Intro

Hi!

I am a researcher at Institute for Artificial Intelligence, University of Bremen. I use MuJoCo for my research on Physics Reasoning.

My setup

MuJoCo 3.2.6
Ubuntu 20.04

My question

Hello everyone, I've encountered a recurring issue that I usually resolve with temporary fixes, but I'd like to find a more permanent solution. The challenge is enhancing the grasping ability of a robot.

Specifically, I'm using the Panda robot hand to try and open a lid by gripping its knob, as well as picking up other loosely placed objects. As demonstrated in the video, the current friction is insufficient for the hand to maintain a secure grip on the knob, despite adjustments to the gripper force and attempts to increase the friction. The pick-and-place tasks are inconsistent, sometimes successful and sometimes not.

GraspingProblem.mp4

Could anyone advise on how to properly manage this scenario?

Minimal model and/or code that explain my question

panda_with_task_board.zip

Confirmations

• I searched the latest documentation thoroughly before posting.
• I searched previous Issues and Discussions, I am certain this has not been raised before.

[yuvaltassa]

Did you read this https://mujoco.readthedocs.io/en/latest/modeling.html#preventing-slip ?

[HoangGiang93]

Thank you for your quick response. Indeed, I review the documents thoroughly each time in an effort to avoid slipping. My issue, however, is that whenever I encounter a new scenario, I need to find a specific configuration tailored to that case. This feels quite like a workaround and leads to inconsistencies. Here’s an example of my current challenge:

I’ve applied all the strategies from the documentation, they only work with the knob when I either set noslip_iterations="1" or higher, or use cone="elliptic" impratio="10". Setting noslip_iterations="1" or higher seems to degrade the physics, while cone="elliptic" impratio="10" appears to work well at the moment, though I’m unsure if it might cause other issues later on.

GraspingProblem.mp4

So my question is, is it a good practice to automatically apply all of these strategies every time I need to simulate grasping and hope for getting lucky?

Merry Christmas to You :)

[yuvaltassa]

cone="elliptic" is always better, but a bit slower.