Units of configuration vector, and order of legs in quadruped example

[JuJuManCheng]

I would like to ask if the unit you used in quadruped example is meters, quaternion and rediant.
For example, the state
q1 = np.array( [0.0, 0.0, 0.235, 0.0, 0.0, 0.0, 1.0, 0.8, -1.6, 0.8, -1.6, -0.8, 1.6, -0.8, 1.6])
Also, I would like to check the order of the legs. Is it consistent with the order of joints in URDF file?
Thanks for yout time.

[stephane-caron]

I would like to ask if the unit you used in quadruped example is meters, quaternion and rediant.

The floating base joint will be in meters + quaternion, while joint angles are indeed in radians (some notes here in case it helps).

Also, I would like to check the order of the legs. Is it consistent with the order of joints in URDF file?

You can check the order of joints to make sure. I believe the quadruped example you are referring to is anymal-simulation.py, in which case the model would be an ANYmal B description. You can check joints by printing out the model:

$ python -i load_in_pinocchio.py anymal_b
Robot successfully loaded as <pinocchio.robot_wrapper.RobotWrapper object at 0x7f792c7dca10>
>>> robot.model
Nb joints = 13 (nq=12,nv=12)
  Joint 0 universe: parent=0
  Joint 1 LF_HAA: parent=0
  Joint 2 LF_HFE: parent=1
  Joint 3 LF_KFE: parent=2
  Joint 4 LH_HAA: parent=0
  Joint 5 LH_HFE: parent=4
  Joint 6 LH_KFE: parent=5
  Joint 7 RF_HAA: parent=0
  Joint 8 RF_HFE: parent=7
  Joint 9 RF_KFE: parent=8
  Joint 10 RH_HAA: parent=0
  Joint 11 RH_HFE: parent=10
  Joint 12 RH_KFE: parent=11

Here I used load_in_pinocchio.py from robot_descriptions.py but you should get the same in the example.

Hoping this helps!

[JuJuManCheng]

Thanks for your reply! I helps a lot! Stéphane Caron ***@***.***> 於 2024年8月14日 週三 下午1:59寫道：

…

I would like to ask if the unit you used in quadruped example is meters, quaternion and rediant. The floating base joint will be in meters + quaternion, while joint angles are indeed in radians (I have some notes here <https://stephane-caron.github.io/pink/introduction.html#pink.configuration.Configuration.get_frame_jacobian> in case it helps). Also, I would like to check the order of the legs. Is it consistent with the order of joints in URDF file? You can check the order of joints to make sure. I believe the quadruped example you are referring to is anymal-simulation.py, in which case the model would be an ANYmal B description. You can check joints by printing out the model: $ python -i load_in_pinocchio.py anymal_bRobot successfully loaded as <pinocchio.robot_wrapper.RobotWrapper object at 0x7f792c7dca10>>>> robot.modelNb joints = 13 (nq=12,nv=12) Joint 0 universe: parent=0 Joint 1 LF_HAA: parent=0 Joint 2 LF_HFE: parent=1 Joint 3 LF_KFE: parent=2 Joint 4 LH_HAA: parent=0 Joint 5 LH_HFE: parent=4 Joint 6 LH_KFE: parent=5 Joint 7 RF_HAA: parent=0 Joint 8 RF_HFE: parent=7 Joint 9 RF_KFE: parent=8 Joint 10 RH_HAA: parent=0 Joint 11 RH_HFE: parent=10 Joint 12 RH_KFE: parent=11 Here I used load_in_pinocchio.py <https://github.com/robot-descriptions/robot_descriptions.py/blob/df5c76e61ffcf87167c4c9ed371b9661c5a9be70/examples/load_in_pinocchio.py> from robot_descriptions.py <https://github.com/robot-descriptions/robot_descriptions.py> but you should get the same in the example. Hoping this helps! — Reply to this email directly, view it on GitHub <#2373 (comment)>, or unsubscribe <https://github.com/notifications/unsubscribe-auth/BFZNCLZT5ZB647VUI6I3U4TZROLJTAVCNFSM6AAAAABMQZMV22VHI2DSMVQWIX3LMV43OSLTON2WKQ3PNVWWK3TUHMZDEOBZGQ4DMNBSGI> . You are receiving this because you authored the thread.Message ID: ***@***.***>