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Generated Schunk .urdf has incorrect orientations

asked 2018-07-03 09:22:57 -0600

lammer18 gravatar image

updated 2018-07-17 15:32:17 -0600

Hello,

I am working with a Schunk LWA 3 (dof 7) arm and controlling it through MoveIt!

I use the below schunk.urdf.xacro and $rosrun xacro xacro.py schunk.urdf.xacro > lwa.urdf to generate a "high-level" urdf file. The attached file calls the lwa.urdf.xacro from Schunk Description

When I use the resulting urdf in MoveIt! setup assistant everything is fine except that the gripper is inverted and the arm is orientated along the -Z axis.

My question is where do I fix the issue? All the values seem to be positive and correct in the urdf's I am using. Where does this change in orientation come from ?

Thank you for your time.

Schunk.urdf.xacro:

<?xml version="1.0"?>
<robot xmlns:sensor="http://playerstage.sourceforge.net/gazebo/xmlschema/#sensor"
xmlns:controller="http://playerstage.sourceforge.net/gazebo/xmlschema/#controller"
xmlns:interface="http://playerstage.sourceforge.net/gazebo/xmlschema/#interface"
xmlns:xacro="http://playerstage.sourceforge.net/gazebo/xmlschema/#interface"
name="schunk" >

<!-- schunk arm -->
<include filename="$(find schunk_description)/urdf/lwa/lwa.urdf.xacro" />

<!-- schunk gripper -->
<include filename="$(find schunk_description)/urdf/pg70/pg70.urdf.xacro" />


<!-- foot for arm-->

<link name="base_link">

<inertial>

<origin xyz="0 0 0" rpy="0 0 0"/>

<mass value="10.0"/>

<inertia ixx="0.1"  ixy="0"  ixz="0" iyy="0.1" iyz="0" izz="0.1" />

</inertial>

</link>

<xacro:schunk_lwa name="arm" parent="base_link">

<origin xyz="0 0 0" rpy="0 0 0" />

</xacro:schunk_lwa>

<xacro:schunk_pg70 name="gripper" parent="arm_7_link">

<origin xyz="0 0 0" rpy="0 0 0" />

</xacro:schunk_pg70>

</robot>
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Comments

It's actually quite easy to format the code, once you know how to do it. Paste it, highlight it, then click the 101010 button (or press Ctrl-k).

jayess gravatar imagejayess ( 2018-07-17 15:31:15 -0600 )edit

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answered 2018-07-17 15:28:48 -0600

lammer18 gravatar image

I fixed this issue by cloning the older groovy-dev branch of schunk_robots, then used the lwa.urdf.xacro in schunk_hardware_config to create the new URDF

This fixes the issue of the arm orientation, next edit the "rpy" values of the grippers orientation in the lwa.urdf.xacro to solve the grippers orientation issues. Rerun the commands to make another "fixed" URDF.

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Asked: 2018-07-03 09:22:57 -0600

Seen: 97 times

Last updated: Jul 17 '18