Contact Sensor seems to be not working correctly

[Icon45]

Hi everyone,

i'm currently trying to implement a contact sensor for a robot, however when i run gz topic -e -t i don't get a response, when the robot must cleary have contact with another object:

this is my implementation of the sensors:

     <!-- ========================================================= -->
      <!--           GAZEBO-KONTAKT-SENSOR für base_link             -->
      <!-- ========================================================= -->
      <gazebo reference="base_link">
        <sensor name="base_link_contact_sensor" type="contact">
          <always_on>1</always_on>
          <update_rate>50</update_rate>
          <visualize>true</visualize>
          <contact>
            <collision>collision</collision>
          </contact>
          <topic>/contacts/base_link</topic>
        </sensor>
      </gazebo>
      <gazebo reference="link_1_s">
        <sensor name="link_1_s_contact_sensor" type="contact">
          <always_on>1</always_on>
          <update_rate>50</update_rate>
          <contact>
            <collision>collision</collision>
          </contact>
          <topic>/contacts/link_1_s</topic>
        </sensor>
      </gazebo>
      <gazebo reference="link_2_l">
        <sensor name="link_2_l_contact_sensor" type="contact">
          <always_on>1</always_on>
          <update_rate>50</update_rate>
          <contact>
            <collision>collision</collision>
          </contact>
          <topic>/contacts/link_2_l</topic>
        </sensor>
      </gazebo>
      <gazebo reference="link_3_u">
        <sensor name="link_3_u_contact_sensor" type="contact">
          <always_on>1</always_on>
          <update_rate>50</update_rate>
          <contact>
            <collision>collision</collision>
          </contact>
          <topic>/contacts/link_3_u</topic>
        </sensor>
      </gazebo>
      <gazebo reference="link_4_r">
        <sensor name="link_4_r_contact_sensor" type="contact">
          <always_on>1</always_on>
          <update_rate>50</update_rate>
          <contact>
            <collision>collision</collision>
          </contact>
          <topic>/contacts/link_4_r</topic>
        </sensor>
      </gazebo>
      <gazebo reference="link_5_b">
        <sensor name="link_5_b_contact_sensor" type="contact">
          <always_on>1</always_on>
          <update_rate>50</update_rate>
          <contact>
            <collision>collision</collision>
          </contact>
          <topic>/contacts/link_5_b</topic>
        </sensor>
      </gazebo>
      <gazebo reference="link_6_t">
        <sensor name="link_6_t_contact_sensor" type="contact">
          <always_on>1</always_on>
          <update_rate>50</update_rate>
          <contact>
            <collision>collision</collision>
          </contact>
          <topic>/contacts/link_6_t</topic>
        </sensor>
      </gazebo>
      <gazebo reference="link_7_m">
        <sensor name="link_7_m_contact_sensor" type="contact">
          <always_on>1</always_on>
          <update_rate>50</update_rate>
          <contact>
            <collision>collision</collision>
          </contact>
          <topic>/contacts/link_7_m</topic>
        </sensor>
      </gazebo>
      <gazebo reference="tool0">
        <sensor name="tool0_contact_sensor" type="contact">
          <always_on>1</always_on>
          <update_rate>50</update_rate>
          <contact>
            <collision>collision</collision>
          </contact>
          <topic>/contacts/tool0</topic>
        </sensor>
      </gazebo>

Console output:

  parallels@ubuntu:~/Desktop/yhc10_ws$ gz topic -l | grep contact 
   /world/sortieranlage/model/yaskawa_hc10/link/base_link/sensor/base_link_contact_sensor/contact
   /world/sortieranlage/model/yaskawa_hc10/link/link_1_s/sensor/link_1_s_contact_sensor/contact
   /world/sortieranlage/model/yaskawa_hc10/link/link_2_l/sensor/link_2_l_contact_sensor/contact
   /world/sortieranlage/model/yaskawa_hc10/link/link_3_u/sensor/link_3_u_contact_sensor/contact
   /world/sortieranlage/model/yaskawa_hc10/link/link_4_r/sensor/link_4_r_contact_sensor/contact
   /world/sortieranlage/model/yaskawa_hc10/link/link_5_b/sensor/link_5_b_contact_sensor/contact
   /world/sortieranlage/model/yaskawa_hc10/link/link_6_t/sensor/link_6_t_contact_sensor/contact
   /world/sortieranlage/model/yaskawa_hc10/link/link_6_t/sensor/link_7_m_contact_sensor/contact
   /world/sortieranlage/model/yaskawa_hc10/link/link_6_t/sensor/tool0_contact_sensor/contact
   /world/sortieranlage/model/yaskawa_hc10/link/link_1/sensor/link_1_s_contact_sensor/contact
   /world/sortieranlage/model/yaskawa_hc10/link/link_2/sensor/link_2_l_contact_sensor/contact
   /world/sortieranlage/model/yaskawa_hc10/link/link_3/sensor/link_3_u_contact_sensor/contact
   /world/sortieranlage/model/yaskawa_hc10/link/link_4/sensor/link_4_r_contact_sensor/contact
   /world/sortieranlage/model/yaskawa_hc10/link/link_5/sensor/link_5_b_contact_sensor/contact
   /world/sortieranlage/model/yaskawa_hc10/link/link_6/sensor/link_6_t_contact_sensor/contact
   /world/sortieranlage/model/yaskawa_hc10/link/tool0/sensor/tool0_contact_sensor/contact
   parallels@ubuntu:~/Desktop/yhc10_ws$ gz topic -e -t /world/sortieranlage/model/yaskawa_hc10/link/tool0/sensor/tool0_contact_sensor/contact

[iche033]

you can debug by turning on contact visualization. Go to top right menu, search for Visualize Contact, set a reasonable radius (for the blue contact visuals) and enable Show Contacts. See if you are getting contacts on the robot.

If there are indeed contacts, it could be that the value of the <collision> sdf element does not point to a valid collision. This could happen if the urdf ->sdf conversion process changes the name of the collision. Try saving the generated SDF file: Go to top left menu, select Save world as, save and inspect the SDF file to see what the SDF looks like for your robot.

[DumbleDuck]

Did we solve the issue? I am currently facing the same problem.