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URDF (with ROS) explodes while SDF (only with Gazebo) works

asked 2018-04-26 12:42:35 -0500

Miriam gravatar image

Hi, I’m trying to make a simulator for a humanoid robot and I stared to construct it only with Gazebo, and with out c ontrol, the robot falls, as it was supposed to do. To start with the control in my robot, I was trying to use the platform of Ros, so, based in the SDF generated in Gazebo, I made a URDF of the robot to run it with ROS, and in ROS, the robot explodes. I have already review the other answers about similar cuestions, and tried to change the inertias (didn’t worked), review the centers of mass (all in their places), I don’t have any control yet, so it can’t be the derivative gain in the PID, and I’m out of ideas, so I was wondering if some one have any other idea of what the problem is about… I’m working with ROS Kinetic and Gazebo 7

URDF

<?xml version="1.0"?>
<!-- Revolute-Revolute Manipulator -->
<robot name="mex_rb" xmlns:xacro="http://www.ros.org/wiki/xacro">


  <!-- Links -->   
    <link name="link_0">
      <inertial>
        <origin xyz="-0.003958 0 1.00846" rpy="0 -1.5707 -1.577"/>
        <mass value="0.598008"/>
        <inertia
          ixx="0.339691"
          ixy="0.0004183"
          ixz="0.0001867"
          iyy="0.0385081"
          iyz="0.0277932"
          izz="0.356779"/>
      </inertial>
      <visual>
        <origin xyz="-0.257058 -0.0781 0.77296" rpy="1.5707 0 1.5707"/>
        <geometry>
        <mesh filename="package://mex_rb/meshes/Stl/Completepart1stl.STL" scale="0.001 0.001 0.001"/>
        </geometry>
      </visual>
      <collision>
        <origin xyz="-0.257058 -0.0781 0.77296" rpy="1.5707 0 1.5707"/>
        <geometry>
        <mesh filename="package://mex_rb/meshes/Stl/Completepart1stl.STL" scale="0.001 0.001 0.001"/>
        </geometry>
      </collision>
    </link>
    <link name="link_1">
      <inertial>
        <origin xyz="-0.003958 0 0.885161" rpy="-0 -1.5707 -1.5707"/>
        <mass value="1.01132"/>
        <inertia
          ixx="0.218719"
          ixy="0.00021"
          ixz="0.0048212"
          iyy="0.381429"
          iyz="0.004079"
          izz="0.356779"/>
      </inertial>
      <visual>
        <origin xyz="-0.257058 -0.0981 0.77296" rpy="1.5707 0 1.5707"/>
        <geometry>
          <mesh filename="package://mex_rb/meshes/Stl/Complete_UpperBodypartstl.STL" scale="0.001 0.001 0.001"/>
        </geometry>
      </visual>
      <collision>
        <origin xyz="-0.257058 -0.0981 0.77296" rpy="1.5707 0 1.5707"/>
        <geometry>
          <mesh filename="package://mex_rb/meshes/Stl/Complete_UpperBodypartstl.STL" scale="0.001 0.001 0.001"/>
        </geometry>
      </collision>
    </link>
    <link name="link_10">
      <inertial>
        <origin xyz="0.003067 0.156075 0.725202" rpy="-0.78535 -1.5707 0"/>
        <mass value="0.009682"/>
        <inertia
          ixx="4.32e-05"
          ixy="0.0"
          ixz="0.0"
          iyy="0.0002238"
          iyz="0.0"
          izz="0.0002238"/>
      </inertial>
      <visual>
        <origin xyz="0.022042 0.13549 0.854522" rpy="-0.000572 1.5707 1.57013"/>
        <geometry>
          <mesh filename="package://mex_rb/meshes/Stl/tubomotorpartstl.STL" scale="0.001 0.001 0.001"/>
        </geometry>
      </visual>
      <collision>
        <origin xyz="0.022042 0.13549 0.854522" rpy="-0.000572 1.5707 1.57013"/>
        <geometry>
          <mesh filename="package://mex_rb/meshes/Stl/tubomotorpartstl.STL" scale="0.001 0.001 0.001"/>
        </geometry ...
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Comments

1

It's fairly difficult to tell what the problem might be from a urdf this huge. You could try removing most links and then start slowly adding links back one-by-one as you see how they behave in the simulation. Once the model explodes you'll know which link caused it.

Raskkii gravatar imageRaskkii ( 2018-04-30 07:39:33 -0500 )edit

Testing all the links separately (and changing some inertias), they work as they are suposed to do, but when I put them together, the model still explodes...

Miriam gravatar imageMiriam ( 2018-05-03 13:50:04 -0500 )edit

And when I constructed it with links and joint, it looks like the joint number 5 doesn't exist and it it declared as the ones before that... here is the video https://youtu.be/7_KUc83YTgU

Miriam gravatar imageMiriam ( 2018-05-03 14:38:00 -0500 )edit

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answered 2018-05-04 12:10:13 -0500

Miriam gravatar image

I had misplaced the joints, I did'tn pass in a correct way the information of the SDF in my URDF

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Asked: 2018-04-26 12:42:35 -0500

Seen: 64 times

Last updated: May 04