How to get a fine-tuned robot model?

[zichunxx]

Hi!

I am trying to get a finely tuned KUKA LBR IIWA 14 R820 model (.xml) from the urdf file.

However, due to the lack of official documentation, I have to start from scratch to get the adjusted joint damping, inertia, and other relevant dynamics parameters. I get a basic kuka model through mujoco200 complie command to convert the urdf to xml.

Currently, the problem I am experiencing is that there is a significant gap between the input joint angle (rad) and the actual joint position (rad), which is not allowed.

Here is a figure to briefly illustrate my situation:

where there is a difference of about 0.1 rad between qpos[1] and joint_a2_T (actuator).

In my XML file, the actuators are set with

  <actuator>
      <position name="joint_a1_T" ctrllimited="true" ctrlrange="-2.9668 2.9668" joint="joint_a1" kp="500"/>
      <position name="joint_a2_T" ctrllimited="true" ctrlrange="-2.0942 2.0942" joint="joint_a2" kp="500"/>
      <position name="joint_a3_T" ctrllimited="true" ctrlrange="-2.9668 2.9668" joint="joint_a3" kp="500"/>
      <position name="joint_a4_T" ctrllimited="true" ctrlrange="-2.0942 2.0942" joint="joint_a4" kp="500"/>
      <position name="joint_a5_T" ctrllimited="true" ctrlrange="-2.9668 2.9668" joint="joint_a5" kp="500"/>
      <position name="joint_a6_T" ctrllimited="true" ctrlrange="-2.0942 2.0942" joint="joint_a6" kp="500"/>
      <position name="joint_a7_T" ctrllimited="true" ctrlrange="-3.0541 3.0541" joint="joint_a7" kp="500"/>
  </actuator>

Could you give me a hint or some help on how to solve this problem and get a fine-tuned model?

Thanks in advance!

[kevinzakka]

Hi @QUIlToT, fyi we have a kuka 14 model that will be released very soon in menagerie so stay on the lookout for that!

[zichunxx]

Great, I will keep following the update of menagerie! Thanks!

[saran-t]

This is now available at https://github.com/deepmind/mujoco_menagerie/tree/main/kuka_iiwa_14

[zichunxx]

@saran-t Thanks for your sharing and work!