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This robot has a joint named "foo" which is not in the gazebo model.

asked 2013-11-18 01:48:07 -0500

lucasw gravatar image

I'm following http://gazebosim.org/wiki/Tutorials/1.9/ROS_Control_with_Gazebo to create my own project and getting this error:

[ERROR] [1384781890.186377319, 0.001000000]: This robot has a joint named "joint_seg_1" which is not in the gazebo model.
[FATAL] [1384781890.186620755, 0.001000000]: Could not initialize robot simulation interface

From the project I've created at https://github.com/lucasw/testbot ( current commit is 0f96ef7fcc8e31ff1bf1883dc10bc32ec440d8f1 )

I think there is something wrong with my joint or transmission, but I'm not seeing it:

<joint name="joint_seg_1" type="revolute">
    <parent link="base_link"/>
    <child link="link_1"/>
    <origin rpy="0 0 0" xyz="0.2 0 0"/>
    <axis xyz="0 0 1"/>
    <limit effort="1000.0" lower="-0.5" upper="0.5" velocity="0.5"/>
    <dynamics damping="0.5"/>
  </joint>
  <transmission name="tran_joint_seg_1">
    <type>transmission_interface/SimpleTransmission</type>
    <joint name="joint_seg_1"/>
    <actuator name="motor_seg_1">
      <hardwareInterface>EffortJointInterface</hardwareInterface>
      <mechanicalReduction>1</mechanicalReduction>
    </actuator>
  </transmission>

The only google hit was the code that outputs the error The code producing the error is https://github.com/pal-robotics/ros_control_gazebo/blob/master/ros_control_gazebo_tests/src/robot_sim_rr.cpp

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3 Answers

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6

answered 2013-11-19 02:58:33 -0500

lucasw gravatar image

I think the problem was that the joint_seg_1 was attached to a link with no physical properties, once I created an extra link below base_link (which as the root is not allowed to have physical properties) the error went away:

<link name="head">
    <visual>
        <origin xyz="0 0 0" rpy="0 0 0" />
        <geometry>
          <mesh filename="package://testbot_description/meshes/cylinder.dae" scale="${seg_length/3} ${seg_length/6} ${seg_length/3}" />
        </geometry>
    </visual>

    <collision>
      <origin xyz="0 0 0" rpy="0 0 0" />
      <geometry>
        <cylinder length="${seg_length/6}" radius="${seg_length/3}" />
      </geometry>
    </collision>

    <inertial>
        <origin xyz="0 0 0" rpy="0 0 0" />
        <mass value="1" />
        <inertia
          ixx="1.0" ixy="0.0" ixz="0.0"
          iyy="1.0" iyz="0.0"
          izz="1.0" />
    </inertial>

</link>

  <joint name="joint_base_head" type="fixed">
        <parent link="base_link" />
        <child link="head" />
        <origin xyz="0 0 0" rpy="0 0 0" />
        <axis xyz="0 0 1" />
  </joint>

<xacro:segment parent="head" postfix="1" length="${seg_length}" width="${seg_width}" height="${seg_height}" />

https://github.com/lucasw/testbot/commit/a883039bcd4d56917bb3e5da89797e48373e1685

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Comments

2

I had the same problem, but it's unclear from your terminology, and it took me a while to understand what you discovered, but incase anyone else was wondering, it's because you were missing the <inertial> tag. And just using an <inertia> tag, which is apparently very different, won't work either.

Cerin gravatar imageCerin ( 2015-05-02 13:21:58 -0500 )edit

The problem occured to me because i used "planar" as a joint type. Gazebo does apparently not support that.

Panda1638 gravatar imagePanda1638 ( 2017-08-24 08:09:04 -0500 )edit
0

answered 2013-11-27 10:52:14 -0500

JoeRomano gravatar image

same problem here, except the child had no physical properties and had to be filled in. too bad no related errror is thrown.

thanks for posting the hint

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0

answered 2015-01-13 19:42:40 -0500

DevonW gravatar image

Just ran into this error myself. Will see if implementing <inertial> <origin xyz="0 0 0" rpy="0 0 0"/> <mass value="1"/> <inertia ixx="1.0" ixy="0.0" ixz="0.0" iyy="1.0" iyz="0.0" izz="1.0"/> </inertial>

into the block fixes the error.

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Asked: 2013-11-18 01:48:07 -0500

Seen: 5,495 times

Last updated: Jan 13 '15