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DRCSIM: Atlas URDF glitches

asked 2013-04-10 13:51:09 -0500

cga gravatar image

1) Torque limits on leg_uhz are not the same: 110 vs 260

/usr/share/drcsim-2.3/ros/atlas_description/urdf/atlas.urdf

<joint name="l_leg_uhz" type="revolute">
    <origin xyz="0 0.089 0" rpy="0 -0 0" />
    <axis xyz="0 0 1" />
    <parent link="pelvis" />
    <child link="l_uglut" />
    <dynamics damping="0.1" friction="0" />
    <limit effort="110" velocity="12" lower="-0.32" upper="1.14" />

<joint name="r_leg_uhz" type="revolute">
    <origin xyz="0 -0.089 0" rpy="0 -0 0" />
    <axis xyz="0 0 1" />
    <parent link="pelvis" />
    <child link="r_uglut" />
    <dynamics damping="0.1" friction="0" />
    <limit effort="260" velocity="12" lower="-1.14" upper="0.32" />

2) As long as we are cleaning up the model. l_lglut:ixy and r_lglut:ixy should have opposite signs, same for lglut:iyz, uglut:ixy, uglut:iyz, lleg:ixz, hand:ixz

3) These links have no inertial fields, so the default mass and moi need to be zero.

link name="right_palm_left_camera_optical_frame"
link name="right_palm_right_camera_optical_frame"
link name="left_palm_left_camera_optical_frame"
link name="left_palm_right_camera_optical_frame"
link name="left_camera_optical_frame"
link name="right_camera_optical_frame"
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answered 2013-04-10 19:59:24 -0500

gerkey gravatar image

For questions 1 and 2, there's a pull request. Some of the moi signs had already been fixed, but a couple had not. Thanks for finding those!

For question 3, those frame just don't factor into simulation. They have no mass, inertia, or other physical properties.

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Comments

This problems have fixed in source files. But, atlas.urdf and atlas_sandia_hands.urdf in debian package (drcsim2.6.1) still remain. ex. effort_limit of r_leg_uhz is 260.

Yohei Kakiuchi gravatar imageYohei Kakiuchi ( 2013-05-19 21:43:06 -0500 )edit
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Asked: 2013-04-10 13:51:09 -0500

Seen: 335 times

Last updated: Apr 10 '13