[Question] Default stiffness and damping gains for robot arm manipulators

[elvisbreit]

Question

I want to tune the PD gains of the robot arm manipulator UR5e with an external load mounted on the flange. I have checked the values provided for the robot in the Isaac Sim Asset Browser and I am wondering on what basis the default damping and stiffness parameters were chosen. The default parameters specifically from the UR5e are shown in the following screenshot if opening the Gain Tuner window:

In general, were these values for all robot arm manipulators derived using the Gain Tuner, and if so, what steps were followed? Or were they obtained through modal analysis, and then used to calculate the stiffness and damping gains?