Hi, thank you. I didn't find anything about that. As I told I can run gazebo, loading only the world file, and it works. But I haven't the robot.

Hi, thank you for your answer. I add the plugin in the .world file. The plugin is working. I can see its effects on the gazebo GUI.

However I also to add these lines to the file you point out

 <gazebo>
 <plugin name="actor1_plugin" filename="libActorPlugin.so">
        <target>0 0 1.21</target>
        <target_weight>1.15</target_weight>
        <obstacle_weight>1.8</obstacle_weight>
        <animation_factor>5.1</animation_factor>
    <room_x>-5.0 5.0</room_x>
    <room_y>-5.0 5.0</room_y>
    <room_z>1.21</room_z>
        <!-- Usage: Modify the set of models that the vector field should
             ignore when moving the actor -->
        <ignore_obstacles>
          <model>ground_plane</model>
        </ignore_obstacles>
      </plugin>
  </gazebo>

But nothing changes.

It seems fine, but probably the plugin is not being loaded or you have some issue exporting the plugin. Run it iand check the log and see what plugins are loaded in gazebo. If your plugin is not listed, then it cannot find or cannot load it properly

This is what happens by adding the plugin to the .xarco file:

[INFO] [1617185974.644589, 0.189000]: ...connected.
Traceback (most recent call last):
  File "/home/alberto/ros/tiago_public_ws/src/tiago_simulation/tiago_gazebo/scripts/tuck_arm.py", line 15, in <module>
    rospy.wait_for_message("joint_states", JointState)
  File "/opt/ros/melodic/lib/python2.7/dist-packages/rospy/client.py", line 428, in wait_for_message
    raise rospy.exceptions.ROSInterruptException("rospy shutdown")
rospy.exceptions.ROSInterruptException: rospy shutdown
[gazebo-2] killing on exit
Segmentation fault (core dumped)
[hand_controller_spawner-9] escalating to SIGTERM
[bringup_controllers_spawner_imu-7] escalating to SIGTERM
[default_controllers_spawner-5] escalating to SIGTERM
[hand_controller_spawner-9] escalating to SIGKILL
[bringup_controllers_spawner_imu-7] escalating to SIGKILL
[default_controllers_spawner-5] escalating to SIGKILL
[rosout-1] killing on exit
[master] killing on exit
Shutdown errors:
 * process[bringup_controllers_spawner_imu-7, pid 30411]: required SIGKILL. May still be running.
 * process[hand_controller_spawner-9, pid 30428]: required SIGKILL. May still be running.
 * process[default_controllers_spawner-5, pid 30398]: required SIGKILL. May still be running.
shutting down processing monitor...
... shutting down processing monitor complete
done

The information log you provided is not sufficient at all, the log shows the information of the controllers alone. If there is a Segmentation fault with your plugin but not without your plugin, then something is wrong with your plugin for sure. Check your plugin for some uninitialized variables and debug the code

I guess this log line means that the plugin is correctly loaded, doesn't it?

[ INFO] [1617211835.384747793]: Finished loading Gazebo ROS API Plugin.

It could be any plugin! If this is the one printed by your plugin then yes. It is loaded but when executing your plugin there is a segmentation fault. So they are two different things.

Finally, the solution is indicated here.