Franka Emika Panda stability for ik with Bullet 2.83

[mert]

Hello,

I am using Franka Emika Panda model available in Coppelia 4.0 (courtesy of Oliva, Cognetti and Gaz from Inria). I needed to use it in inverse kinematics mode, so I turned joints from torque/force mode to inverse kinematics with hybrid operation option. While the model was running in Bullet 2.78 engine, it seemed to be working. But for some other reason I needed to switch to Bullet 2.83 pyhsics engine, and now the robot is shaking.

I tried to change target precision for ik, and changing the weight of the last link which is the only one dynamically enabled.

I do not know why this shaking is caused by. If anybody with a solution or idea on a similar issue that would be great.

Best

[coppelia]

Hello,

if the shaking appeared after switching to another engine, then you have the reason for it. Try to check if the chaking also happens with some of the other engines. But it is most probably linked to some parameters/values that need to be adjusted:

Try to adjust individual joint's maximum torque, and/or the PID parameters. Also, try to adjust the inertia (and maybe also mass) of the various robot links (e.g. increasing the inertia sometimes works wonders. Read more about this in design considerations 7-8.

Cheers

[mert]

Dear Coppelia,

It was shaking with all available engines except bullet 2.78. But as you suggested, increasing the inertia of all respondable links to double helped! Thank you!