[Question] How to control position mode actuactor in isaac-lab2.0?

[Diligent06]

I use RoboVerse framework and select Isaac-lab simulator. I construct a franka arm in simulator and I want to finish mobile manipulation tasks in a scene. All joints in franka are controlled by position mode. But I found that when I grasp an object in hand and going to move to another position, gripper of franka will be released and drop out object in hand. I found that this may be because the simulator simulates centrifugal force. I attempted to adjust P and D parameters of each actuactor but It is no effect.
Is there anyone who suffer the same situation with me or someone who can help me solve this problem?
Sincere thanks!

[RandomOakForest]

Thank you for posting this. The object is slipping because the gripper’s position-controlled PD drive is saturating or being “soft” under inertial loads, not because of a special “centrifugal force” model, and increasing only P/D on the arm joints won’t fix gripper holding force. The fix is to give the gripper sufficient holding force (effort limits), proper impedance, contact/friction, and solver fidelity; if needed, switch the gripper to velocity/effort control with force limits or a joint impedance controller that includes gravity/inertial compensation.¹²

I'll move this post to our Discussions section for follow up by the team and others.

Footnotes

1. https://isaac-sim.github.io/IsaacLab/main/source/api/lab/isaaclab.actuators.html ↩

2. https://isaac-sim.github.io/IsaacLab/main/source/overview/core-concepts/motion_generators.html ↩