jacky_90's profile - activity

Hello everyone. I started programming the ardrone using ROS (I'm a newbie to both) and i wanted to implement a basic form of odometry of the kind px = px + (vxcos(...) - vysin(...)), py = ..., using the speed information provided from the navdata. Unfortunately, in this way a lot of error is introduced. Since i've never used ROS, i wanted to know if there is a better way to do this, i mean, if ROS offers a way to keep track of the position of the drone.

Thank you in advance.

Hello everyone. I needed to pass to Ubuntu 64 bit in order not to have problems with the package ar_track_alvar. I was working with the ardrone_autonomy package, which did work fine until i was on 32 bit. Now, when i launch the node, i get the following error:

fuerte_workspace/ardrone_autonomy/bin/ardrone_driver: error while loading shared libraries: libimage_transport.so: wrong ELF class: ELFCLASS64

and the process dies. Any idea to how to fix this? Thanks in advance!

Hello everyone. I've been trying to make the ros-gazebo simulator working with 2 or more drones, with no result. Using rostopic list, the topics appear with the right name (/ardrone/takeoff and /ardrone_2/takeoff etc.) but when I send a command, only one drones is receiving them, often with unexpected outcomes (it flies away =( ))

Here is my launch file,

<?xml version="1.0"?>

<launch>

  <!-- Start Gazebo with wg world running in (max) realtime -->
  <arg name="gui" default="true"/>

  <param name="/use_sim_time" value="true" />

  <node name="gazebo" pkg="gazebo" type="gazebo" args="$(find cvg_sim_gazebo)/worlds/3boxes_room.world" respawn="false" output="screen"/>
    <!-- start gui -->
  <group if="$(arg gui)">
    <node name="gazebo_gui" pkg="gazebo" type="gui" respawn="false" output="screen" required="true"/>
  </group>

  <group ns="ardrone">
  <!-- Spawn simulated quadrotor uav -->
  <include file="$(find cvg_sim_gazebo)/launch/spawn_quadrotor_classic.launch" >
    <arg name="model" value="$(find cvg_sim_gazebo)/urdf/quadrotor_sensors.urdf.xacro"/>
    <arg name="init_pose" value="-x 0 -y 0 -z 0.5"
  </include>
  </group>

  <group ns="ardrone_2">
  <!-- Spawn simulated quadrotor uav -->
  <include file="$(find cvg_sim_gazebo)/launch/spawn_quadrotor_classic.launch" >
    <arg name="model" value="$(find cvg_sim_gazebo)/urdf/quadrotor_sensors.urdf.xacro"/>
    <arg name="init_pose" value="-x 1 -y 0 -z 0.5"
  </include>
  </group>

</launch>

while the spawn_quadrotor_classic launch file is,

 <launch>
   <arg name="model" default="$(find cvg_sim_gazebo)/urdf/quadrotor.urdf.xacro"/>
   <arg name="init_pose" />
   <!-- send the robot XML to param server -->
   <param name="robot_description" command="$(find xacro)/xacro.py '$(arg model)'" />

   <!-- push robot_description to factory and spawn robot in gazebo -->
   <node name="spawn_robot" pkg="gazebo" type="spawn_model"
   args="-param robot_description
   -urdf
   $(arg init_pose)
   -model quadrotor"
     respawn="false" output="screen"/>

   <!-- start robot state publisher -->
   <node pkg="robot_state_publisher" type="state_publisher" name="robot_state_publisher" output="screen" >
     <param name="publish_frequency" type="double" value="50.0" />
     <param name="tf_prefix" type="string" value="" />
   </node>

   <node name="ground_truth_to_tf" pkg="message_to_tf" type="message_to_tf" output="screen">
     <param name="odometry_topic" value="ground_truth/state" />
     <param name="frame_id" value="nav" />
   </node>
   <!-- node name="hector_pose_estimation" pkg="hector_pose_estimation" type="hector_pose_estimation_node" output="screen"/-->

 </launch>

Any help would be appreciated! Thank you!

I contacted the developer some time ago. He said that the simulator is structured in such a way that allows the spawning of only a single robot at each time.

Hello everyone. I'm having issues with the control of 3 ardrones, each one connected to its laptop, where one of these laptos is configured as the master.

The network is configured properly.

The first problem occured with 2 drones. When flying togheter, I kept getting the following error "Reconnecting ... Reconnecting ... Timeout when reading navdatas - resending a navdata request on port 5554"

So I firstly switched from the 200 hz of the navdata msgs sent from the drone to 15 hz, and I set the drone driver loop from 50 to 20. The two drones where then able to fly togheter. When I added the third, unfortunately, the error reappeared.

In my nodes I write on a custom topic the informations relative to each drone (I send them each 300 ms), I have 2 loops repeating at 200 and 100 ms, and on each laptop two nodes for marker detection (ar_track_alvar package)

Does anyone have an idea of how to make the system work robustly with 3 drones?

Thank you!

Hello everyone. I was looking for a good tutorial to learn how to use ar_pose. Thank you in advance!

Hello everyone. I followed the instructions at https://github.com/AutonomyLab/ardrone_autonomy/wiki/Multiple-AR-Drones for using multiple parrots. With 2 robots, the network works fine. However, when I add the third, after a while, I get the following error: Timeout when reading navdatas - resending a navdata request on port 5554 and the network is not able to recover. This happens also if I set the "codec_fps" parameter to 1. Does anyone know if it is possible to solve this issue? Thank you.

Hello everyone. I want to display a marker in rviz with the shape of a person. I found a .dae model on the web. I send the marker information trough the proper topic and I am able to visualize the mesh model in rviz. The problem is that, when I use some keyboard command to make the model rotate, it does not. It is strange because I am displaying other robots as "marker" and they receive the orientation (obviously the code I am using is the same). I've never created a .dae model and looking into the file I cannot figure out what is wrong =( Any expert? Otherwise, can someone tell me where I can find mesh models of a "person" (even a humanoid robot is ok) that can work in rviz?

Thank you.

Thank you very much!

Hello. I've got a problem with topic remapping. I have a node that publishes informations relative to a robot, and listens to the topics of the informations relative to other 3 robot of the same type. Something like:

publish on : /robot1/info listens to: /robot2/info , /robot3/info, /robot4/info.

Now I want all the 4 robots to share the same code.

So, I want, for example, robot2 to publish on /robot2/info and to listen to /robot1/info (and to the other 2 robots of course)

In the launch file a used a classic remap in this way: from="/robot1/info" to="/robot2/info" and from="/robot2/info" to="/robot1/info"

but the result is that nothing changes and I think is due to some kind of circular remapping.

Any idea of how to address the problem? Thank you in advance.