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2019-12-13 09:10:33 -0500 commented answer how to visualize pcd file.??

thanks Felix!

2019-12-13 05:08:13 -0500 edited question cannot run octomap simple_example.cpp

cannot run octomap simple_example.cpp Hi guys, I am trying to run use the octomap library and wanted to run the simple_

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2019-12-12 11:53:34 -0500 edited question cannot run octomap simple_example.cpp

cannot run octomap simple_example.cpp Hi guys, I am trying to run use the octomap library and wanted to run the simple_

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2019-12-11 11:39:34 -0500 commented answer no timestamps when publishing for fixed joints robot_state_publisher

yes, set use_sim_time to true in your launch file when launching gazebo and it should solve your problem. <arg name=

2019-12-11 11:34:44 -0500 asked a question cannot run octomap simple_example.cpp

cannot run octomap simple_example.cpp Hi guys, I am trying to run use the octomap library and wanted to run the simple_

2019-12-11 11:30:38 -0500 asked a question cannot run octomap simple_example.cpp

cannot run octomap simple_example.cpp Hi guys, I am trying to run use the octomap library and wanted to run the simple_

2019-11-29 07:44:19 -0500 received badge  Popular Question (source)
2019-10-25 03:37:12 -0500 marked best answer no timestamps when publishing for fixed joints robot_state_publisher

Hi guys,

I have the following problem: I wrote a launch file which launches my differential drive robot with 2 lidar sensors in gazebo and rviz. The odometry for my robot comes from the differential drive plugin and the transforms for my robot come from the nodes "robot_sate_publisher" and "joint_state_publisher". I have 3 fixed joints "base_link" to "chassis" and "chassis" to each of the lidars and 2 continuous joints "chassis" to "wheel" for each wheel. Now when I look at the rqt_tree I see that the transforms for all the fixed joints, there is no time_stamp for the transforms and also I cannot choose to see the Pointcloud data in the odom frame since rviz tells me that the message was removed, because it is too old.

My question: do I have to code now a separate node which broadcasts all these transforms with a time stamp? I thought that the robot_state_publisher and joint_state_publisher nodes that I launch in the launch-file are exactly for that: to publish all the transforms (whole transform tree) of my robot. But I only get stamped messages for the chassis to wheel tranforms and odom to base_footprint transforms but not for the fixed joints. (I already tried with static_transform nodes to publish static transforms, but still no timestamp)

Launch File:

<launch>

  <!--Robot Description from URDF-->
  <param name="robot_description" command="$(find xacro)/xacro $(find sim_1)/urdf/robot.xacro"/>  

  <node name="robot_state_publisher" pkg="robot_state_publisher" type="state_publisher"/>

  <node name="joint_state_publisher" pkg="joint_state_publisher" type="joint_state_publisher"/>

  <!--node pkg="tf" type="static_transform_publisher" name="to_chassis" args="0 0 0.35 0 0 0 /base_footprint /chassis 50"/>

  <node pkg="tf" type="static_transform_publisher" name="to_laser_back" args="-0.45 -1 1.25 0 0 0 /chassis /sensor_laser_back  50"/>

  <node pkg="tf" type="static_transform_publisher" name="to_laser_front" args="0.45 1 1.25 0 0 0 /chassis /sensor_laser_front  50"/-->

  <!--RViz-->
  <node name="rviz" pkg="rviz" type="rviz" required="true"/>

  <!--Gazebo empty world launch file-->
  <include file="$(find gazebo_ros)/launch/empty_world.launch">
        <arg name="debug" value="false" />
        <arg name="gui" value="true" />
        <arg name="paused" value="false"/>
        <arg name="use_sim_time" value="false"/>
        <arg name="headless" value="false"/>
        <arg name="verbose" value="true"/>
  </include>

  <!--Gazebo Simulator-->
  <node name="spawn_model" pkg="gazebo_ros" type="spawn_model" args="-urdf -param robot_description -model robot" output="screen"/>

</launch>

Thank you very much in advance!image description

2019-10-25 03:23:34 -0500 commented answer no timestamps when publishing for fixed joints robot_state_publisher

cool, thank you!

2019-10-25 03:23:20 -0500 edited question no timestamps when publishing for fixed joints robot_state_publisher

no timestamps when publishing for fixed joints robot_state_publisher Hi guys, I have the following problem: I wrote a l

2019-10-25 03:14:50 -0500 answered a question no timestamps when publishing for fixed joints robot_state_publisher

so it seems to be normal to not get any timestamps when publishing fixed joint transforms via robot_state_publisher as c

2019-10-25 02:38:16 -0500 commented question What is the problem with my odom fixed frame

I have the exact same problem...were you able to solve it? Thank you in advance.

2019-10-21 09:06:17 -0500 asked a question no timestamps when publishing for fixed joints robot_state_publisher

no timestamps when publishing for fixed joints robot_state_publisher Hi guys, I have the following problem: I wrote a l

2019-10-17 07:10:11 -0500 commented answer joint state publisher dies, cannot attach wheels with continuous joint

thank soo much!

2019-10-17 07:08:45 -0500 received badge  Supporter (source)
2019-10-17 07:08:43 -0500 marked best answer joint state publisher dies, cannot attach wheels with continuous joint

Hi,

I am currently trying to create a simple differential drive robot model with 2 wheels and 2 caster wheels, but I cannot attach the wheels to the chassis with continuous/revolute joints and I do not get the transforms of course, but I can connect them with fixed joints and I also get the correct transforms with the fixed joints.

I am using ros melodic with Ubuntu 18.04.3 LTS on VM 6.0.12

  • /rosdistro: melodic
  • /rosversion: 1.14.3

Here is the error message I get:

Error Message

SUMMARY

PARAMETERS 
* /joint_state_publisher/use_gui: True 
* /robot_description: <?xml version="1....
* /rosdistro: melodic
* /rosversion: 1.14.3

NODES 
/ joint_state_publisher (joint_state_publisher/joint_state_publisher)
 robot_state_publisher (robot_state_publisher/state_publisher) 
 rviz (rviz/rviz)

auto-starting new master 
process[master]: started with pid [18519] 
ROS_MASTER_URI=http://localhost:11311

setting /run_id to 2a1bb272-f0b9-11e9-b0ed-080027935df5 
process[rosout-1]: started with pid [18530] 
started core service [/rosout] 
process[joint_state_publisher-2]: started with pid [18533] 
process[robot_state_publisher-3]: started with pid [18538] 
process[rviz-4]: started with pid [18539] 
Traceback (most recent call last): File "/opt/ros/melodic/lib/joint_state_publisher/joint_state_publisher", line 474, in jsp = JointStatePublisher() 
File "/opt/ros/melodic/lib/joint_state_publisher/joint_state_publisher", line 149, in init robot = xml.dom.minidom.parseString(description) 
File "/usr/lib/python2.7/xml/dom/minidom.py", line 1928, in parseString return expatbuilder.parseString(string) 
File "/usr/lib/python2.7/xml/dom/expatbuilder.py", line 940, in parseString return builder.parseString(string) 
File "/usr/lib/python2.7/xml/dom/expatbuilder.py", line 223, in parseString parser.Parse(string, True) 
UnicodeEncodeError: 'ascii' codec can't encode character u'\u202c' in position 5988: ordinal not in range(128) [joint_state_publisher-2] process has died [pid 18533, exit code 1, cmd /opt/ros/melodic/lib/joint_state_publisher/joint_state_publisher __name:=joint_state_publisher __log:=/home/user/.ros/log/2a1bb272-f0b9-11e9-b0ed-080027935df5/joint_state_publisher-2.log]. log file: /home/user/.ros/log/2a1bb272-f0b9-11e9-b0ed-080027935df5/joint_state_publisher-2*.log

URDF file

<?xml version="1.0" ?>
<robot name="mybot">

  <link name="base_footprint"/>

  <joint name="base_joint" type="fixed">
    <parent link="base_footprint"/>
    <child link="chassis" />
    <origin xyz="0 0 0.010" rpy="0 0 0"/>
  </joint>

  <link name="chassis">
    <collision name="base_collision">
      <origin rpy="0 0 0" xyz="0 0 0.35"/>
      <geometry>
        <box size="1 1.8 0.4"/>
      </geometry>
    </collision>
    <visual name="base_visual">
      <origin rpy="0 0 0" xyz="0 0 0.35"/>
      <geometry>
        <box size="1 1.8 0.4"/>
      </geometry>
    </visual>
    <collision name="l_side_collision">
      <origin rpy="0 0 0" xyz="-0.475 0 1.18"/>
      <geometry>
        <box size="0.05 1.8 2.0"/>
      </geometry>
    </collision>
    <visual name="l_side_visual">
      <origin rpy="0 0 0" xyz="-0.475 0 1.18"/>
      <geometry>
        <box size="0.05 1.8 2.0"/>
      </geometry>
    </visual>
    <collision name="r_side_long_collision">
      <origin rpy="0 0 0" xyz="0.475 0.45 1.18"/>
      <geometry>
        <box size="0.05 0.9 2.0"/>
      </geometry>
    </collision>
    <visual name="r_side_long_visual">
      <origin rpy ...
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2019-10-17 04:35:56 -0500 asked a question joint state publisher dies, cannot attach wheels with continuous joint

joint state publisher dies, cannot attach wheels with continuous joint Hi, I am currently trying to create a simple dif