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2015-03-30 03:19:48 -0500 asked a question [2D Navigation (3D Outdoor, Hills etc...) ] What package to use?

Hi,

I would like to know about the best ways to navigate with 2D in a 3D Environment (Outdoor) (GPS, IMU, Odometry).

Is nav2D still state of the art or is using something else more recommended?

Is there a way to navigate a robot with MoveIt? Examples?

Thanks!

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2015-03-13 12:58:28 -0500 commented answer How to calibrate libgazebo imu or any other imu for slam?

Hmm, I also thought about using that one, I will try ...

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2015-03-13 05:13:34 -0500 asked a question How to calibrate libgazebo imu or any other imu for slam?

Hi, I found the service from the imu (/default/imu) which is a std_srv/empty service. Is it just calling and turning the robot or what do I have to do?

I already searched and did not find any nice tutorial on google about how to do imu calibration in ROS. I also can't find the github libgazebo_plugins repo on google somehow (I think this is really weired, but I know it is there so I can find it) So I guess I might be missing something about the imu too. Can you give me a hint what to do and how? Because the simulated Gyro is somewhat off and slam is working only when driving forward and backward, but looks totally ugly when turning.

Actually the world is containing just a standard cube from Gazebo. That's what it looks when I drive around it.

The IMU is placed in the center between the wheels on the axis. (Diff drive) I am also using robot_localization ukf to fuse the IMU and the Odometry.

image description

Thanks in advance.

2015-03-12 09:12:08 -0500 commented answer Catkin Problems on sourcing workspaces

Ah yes I found that out now too, I need to source the one first which was built first. Because the second one depends on the first one when it was sourced on build time. I just adjusted my build script for that and now it seems to work.

2015-03-12 08:12:56 -0500 asked a question Catkin Problems on sourcing workspaces

Hi,

I am currently trying to source multiple catikin workspaces but I mostly get only one to work, which is the last one I include.

What is the problem there?

It was working most of the time but, right now it does not anymore. When it was working I always had to include one workspace after another one. If I reverted the order only one of them was found.

But now I am always getting only one workspace to work.

Any idea what's the reason for that?

Thanks!

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2015-03-11 13:59:17 -0500 answered a question Robot model in rviz is not following base link

After looking in the turtlebot navigation rviz view I found my mistake. I was using Robot State Plugin instead of Robot Model. When using the Robot Model plugin it just works fine.

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2015-03-09 06:43:48 -0500 commented answer Gazebo and Real world Contact Sensors.

Hmm, think so too...

2015-03-09 04:13:03 -0500 commented answer Can I define a xacro with params by another xacro?

Me too, I just wanted to ask and see if I am right.

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2015-03-06 10:58:03 -0500 commented question Robot model in rviz is not following base link

Can you confirm the behaviour or is there a problem with my model or something else?

2015-03-06 09:09:03 -0500 answered a question Spawning multiples robots with 1 URDF/XACRO file

I just tried it myself with my robot. One thing you need are groups in launchfiles.

http://wiki.ros.org/roslaunch/XML/group

BTW. If you use robot namespace tags in your model plugins, remove them!

Otherwise your topics like for example cmd_vel will overlap.

You also need another parameter with a different name for the other robot because I found out they are named like the param in gazebo.

Put the same launch tags (except the parameter for the spawn and spawn position) for your robots in two tags,

For example:

<node name="spawn_test_bot" pkg="gazebo_ros" type="spawn_model" args="-z 0.1 -urdf -param robot_description -model robot_description" respawn="false" />

 <node name="spawn_test_bot" pkg="gazebo_ros" type="spawn_model" args="-z 0.1 -x 1 -urdf -param robot_description2 -model robot_description2" respawn="false" />

That seems to work for me, but currently I just need one robot.

2015-03-06 03:45:43 -0500 asked a question Can I define a xacro with params by another xacro?

Hi I am trying to define a xacro macro with another macro. But I am getting an error about one of the internal params from the macro. Is there an escape sequence or something for that?

Currently I get the error:

raise XacroException("Property wasn't defined: %s" % str(ex)) xacro.XacroException: Property wasn't defined: u'name'

<xacro:macro name="rr_mat_gaz_color_def" params="color material">
    <xacro:macro name="rr_mat_gaz_${color}" params="name material">
       <gazebo reference="${name}_link">
        <material value="${material}" />
       </gazebo>
    </xacro:macro>
</xacro:macro>

Thanks!

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2015-03-03 07:22:53 -0500 asked a question Gazebo and Real world Contact Sensors.

Hi,

I want to simulate a Service robot which features bumpers and also I want to build a real one. Now the question is, what topics to use? The Bumper plugin for Gazebo outputs a lot of information on the contact, but I only want to know if it is pressed or not. Also when it is in the Gazebo package, I guess it should be used for simulation only, right?

What topic shall I use for real sensors?

Bool?

And how to interface Gazebo? Do I have to write my own node to get the pressed state from the topic? Or is there somehing ready to use?

How do I interface this to already available ROS planing systems? Is there a common way to do this? Or do I have to add Obstacles to the costmap myself somehow, when a bumper is being pressed?

Thanks!

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2015-02-26 13:52:19 -0500 asked a question Why is my simulated bumper not working?

I have checked out multiple sources for simulated bumpers in Gazebo and I tried a lot of them. I tried to copy stuff from a lot of models into mine and tried to hook it up but it won't work and gazebo is crashing most of the time or it does not post any topic.

Could somebody please tell me what is wrong with this piece of code? (URDF model)

Thanks!

 <link name="bumper0">
    <visual>
        <geometry>
            <box size="0.1 0.1 0.1" />
        </geometry>
    </visual>
    <collision name="bumper0_collision">
        <geometry>
            <box size="0.1 0.1 0.1" />
        </geometry>
    </collision>
</link>

<joint name="chassis_bumper_joint" type="fixed">
    <parent link="chassis" />
    <child link="bumper0" />
    <origin xyz="1 0 0" rpy="0 0 0" />
</joint>    


<gazebo reference="bumper0">
  <sensor name="bumper0_contact_sensor" type="contact">
    <always_on>true</always_on>
    <update_rate>30.0</update_rate>
    <contact>
      <collision>bumper0_collision</collision><!-- What should go here? The name of the collision? Or some special syntax???-->
    </contact>
    <plugin name="gripper_bumper" filename="libgazebo_ros_bumper.so">
      <bumperTopicName>bumper0_topic</bumperTopicName><!-- Topic name -->
      <frameName>bumper0_frame</frameName><!-- Frame id-->
    </plugin>
  </sensor>
</gazebo>

What I get:

[INFO] [WallTime: 1424980069.535978] [0.043000] Calling service /gazebo/spawn_urdf_model * Internal Program Error - assertion (this->customContactPublishers.count(name) > 0) failed in std::string gazebo::physics::ContactManager::CreateFilter(const string&, const std::vector<std::basic_string<char> >&): /tmp/buildd/gazebo2-2.2.3/gazebo/physics/ContactManager.cc(329): Failed to create a custom filter Aborted (core dumped) Service call failed: transport error completing service call: unable to receive data from sender, check sender's logs for details

2015-02-26 10:04:06 -0500 commented question Robot model in rviz is not following base link

The current one from the repository for Ubuntu 14.04 64 Bits.

[ INFO] [1424966599.084140166]: rviz version 1.11.4
[ INFO] [1424966599.084295977]: compiled against OGRE version 1.8.1 (Byatis)
[ INFO] [1424966600.923199210]: Stereo is NOT SUPPORTED
[ INFO] [1424966600.923288004]: OpenGl version: 4.4
2015-02-25 08:46:05 -0500 asked a question Robot model in rviz is not following base link

Hi,

I am using Gazebo with a simulated model with GPS, IMU and Odometry from the diff drive including the navsat and the ukf node, the estimation is not correct yet, but I wonder about something else:

My robot model does not move in rviz.

In rviz I have set up the fixed frame to map. The tfs are generated and I see them in Rviz, the tf links are moving around and the wheel tfs also rotate when doing so, but the rendered robot model keeps staying at the initial position. It is like that now, but before I could uncheck and check the checkbox of the robot state and the robot moved to the base_link to stick in that position till I do that unchecking and checking again. But that also does not work anymore.

Somehow it is just at the right place when setting fixed frame to base link, so the robot model is always following the fixed frame. But shouldn't it follow the "Robot Root Link"? (set to base_link)

Has anybody an idea what I am doing wrong?

Thanks in advance, for any help.