fer_link4 has invalid inertia

[Anas-Gouda]

the ros distro is : humble
the os distro is : ubuntu 22.04

when simulating the fer robot in gazebo using this command :

ros2 launch franka_gazebo_bringup visualize_franka_robot.launch.py arm_id:=fer

it gives this error in both gazebo and rviz:

[rviz2-3] [ERROR] [1756212154.628999872] [rviz2]: The link fer_link4 is has unrealistic inertia, so the equivalent inertia box will not be shown.

[ign gazebo-1] [Err] [UserCommands.cc:1138] Error Code 18: Msg: A link named fer_link4 has invalid inertia.

the inertial parameter for the forth link is:

link4:
  origin:
    xyz: -0.05113 0.05825 0.01698
    rpy: 0 0 0
  mass: 2.2037
  inertia:
    xx: 0.00784585566
    xy: -0.00339591957
    xz: 0.00158704074
    yy: 0.00649543136
    yz: -0.00181477884
    zz: 0.01003079917

Another thing, according to the franka emika panda robot (fer) Product Manual Franka Emika Robot_10.21_EN the total weight of the robot is about 17.8 kg, but by summing all the links in the inertia.yaml file for the fer robot it is less that the manual by 1.617 kg.

https://download.franka.de/documents/100010_Product%20Manual%20Franka%20Emika%20Robot_10.21_EN.pdf

[AndreasKuhner]

Hi @AnasGoda ,
the FER inertial values are not official values and are just 'optimized' values from the community. Aka, they work for computing dynamics but they don't match the real values.

But you can just use the fp3 or fr3 for the simulation... there are no kinematic/dynamic differences between FER and fp3/fr3. For those guys we shared valid values.

Cheers,
Andreas