Gazebo | Ignition | Community
Ask Your Question

Revision history [back]

click to hide/show revision 1
initial version

Toggling contact of wheel

I have created a model by using the URDF export plugin for SolidWorks and converted it into the SDF format. In Gazebo some joints start moving. The problem appears to be a toggling contact of the wheel with the ground. Please watch the youtube video to understand what I am refering to.

3 wheel robotic platform in gazebeo

The video is x10 times the normal speed, as the movement is very small. Unfortunately I cannot upload the SDF file in lack of Karma.

so here is a sniplet of the wheel

 <link name='rad'>
  <pose>0.0724995 0 -0.435 -1.57079 0 0</pose>

  <inertial>
    <pose>0 0 0 0 -0 0</pose>
    <mass>0.54391</mass>
    <inertia>
      <ixx>0.0034711</ixx>
      <ixy>0</ixy>
      <ixz>0</ixz>
      <iyy>0.0034739</iyy>
      <iyz>0</iyz>
      <izz>0.0061305</izz>
    </inertia>
  </inertial>

  <collision name='rad_collision'>
    <pose>0 0 0 0 -0 0</pose>
    <geometry>
    <cylinder>
        <radius>0.130</radius> 
        <length>0.09</length>
    </cylinder>
      <!-- <mesh>
        <scale>1 1 1</scale>
        <uri>file://rad.dae</uri>
      </mesh> -->
    </geometry>

<surface>
      <friction>
        <ode>
          <mu>10.0</mu>
          <mu2>10.0</mu2>
          <slip1>10</slip1>
          <slip2>10</slip2>
        </ode>
    <bullet>
    <friction>10.0</friction>
    <friction2>10.0</friction2>
    <fdir1>1 1 0</fdir1>
    <rolling_friction>1.0</rolling_friction>
    </bullet>
      </friction>

  <contact>
    <ode>
        <soft_cfm>0</soft_cfm>
        <soft_erp>0.1</soft_erp>
        <kp>1e+10</kp>      
        <kd>10</kd>
        <max_vel>0.01</max_vel>
        <min_depth>1</min_depth>
    </ode>
  </contact>
  </surface>

And thats the sniplet for the corresponding joint

 <joint name='Jrad' type='revolute'>
  <child>rad</child>
  <parent>gabel</parent>
  <axis>
    <xyz>0 1 0</xyz>
    <limit>
      <lower>-1e+16</lower>
      <upper>1e+16</upper>
    </limit>
    <dynamics>
    <damping>0.8</damping>
    <friction>0.0001</friction>
    </dynamics>
  </axis>
</joint>

I have tried different values for mu, friction friction etc. with limited success. Maybe someone sees the error in my approach.


The system i am working on:

OS: Ubuntu 3.8.0-35-generic #50~precise1-Ubuntu SMP Wed Dec 4 17:25:51 UTC 2013 x86_64 x86_64 x86_64 GNU/Linux

Gazebo: version 2.1.0

ROS: Furete

BR and thanks for any help in advance!