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tf listener does not see specified links in URDF file

asked 2020-02-10 01:24:11 -0500

stefvanlierop gravatar image

updated 2020-02-10 07:37:06 -0500

Hi, i have been working with a UR10 and need to have the position of the TCP in real time. In a previous post, people recommended me to build a TF listener and when i got that working i could indeed track the position. I still had some position errors in general and therefore i downloaded and installed the Universal_Robots_ROS_Driver. But now, the TF_2 program does not seem to see links other then those specified by the original URDF of the UR10. I can see this when i echo the tf topic. I expect to see all links attached, but i only see the links that are defined in the URDF of the UR10. I find this really strange i get no errors and RVIZ does load all the links and elements that are specified. The moveit! setup assistant also loads all links.

I simply build the tf_listner from [this tutorial] ( and switched the names of the link. The links that i am missing should be attached to tool0 ans would go to a tool_tcp. Tool is the prefix i defined in the URDF. I also miss the table links who have the prefix table_

I only changed the default parameters to the parameters that i already have defined. Like the ip adress of the robot.

        <?xml version="1.0"?>   
    <arg name="debug" default="false" doc="Debug flag that will get passed on to ur_common.launch"/>  
    <arg name="robot_ip" default = "" doc="IP address by which the robot can be reached."/>   
    <arg name="reverse_port" default="50001" doc="Port that will be opened by the driver to allow direct communication between the driver and the robot controller."/>   
    <arg name="script_sender_port" default="50002" doc="The driver will offer an interface to receive the program's URScript on this port. If the robot cannot connect to this port, `External Control` will stop immediately."/>  
    <arg name="tf_prefix" default="" doc="tf_prefix used for the robot."/>   
    <arg name="controllers" default="joint_state_controller scaled_pos_traj_controller speed_scaling_state_controller force_torque_sensor_controller" doc="Controllers that are activated by default."/>  
    <arg name="stopped_controllers" default="pos_traj_controller" doc="Controllers that are initally loaded, but not started."/>  
    <arg name="controller_config_file" default="$(find ur_robot_driver)/config/ur10_controllers.yaml" doc="Config file used for defining the ROS-Control controllers."/>   
    <arg name="robot_description_file" default="$(find ur_description)/launch/ur10_upload.launch" doc="Robot description launch file."/>   
    <arg name="kinematics_config" default="$(find ur_description)/config/ur10_default.yaml" doc="Kinematics config file used for calibration correction. This will be used to verify the robot's calibration is matching the robot_description."/>  
    <arg name="limited" default="false" doc="Use the description in limited mode (Every axis rotates from -PI to PI)"/>   <arg name="headless_mode" default="false" doc="Automatically send URScript to robot to execute. On e-Series this does require the robot to be in 'remote-control' mode. With this, the URCap is not needed on the robot."/>   

    <include file="$(find ur_robot_driver)/launch/ur_common.launch">
        <arg ...
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the TF does not seem to see links other then those specified by the original URDF of the UR10

this is a little vague. "the TF" does not really exist.

Please post a rqt_tf_tree screenshot, a concrete example of some code that used to work but no longer does and show us how you start things (ie: which .launch files, etc).

Update your original question text with this information. Use the edit button/link to do that.

gvdhoorn gravatar image gvdhoorn  ( 2020-02-10 02:01:22 -0500 )edit

Could you check the formatting of your question? Some of the copy-pastes have turned out a bit jumbled.

General workflow:

  1. paste a verbatim copy of the text you want to include
  2. select it
  3. press ctrl+k or click the Preformatted Text button (101010)

Do not just select the first line for step 2. Make sure to select all text you want to format.

I simply build the tf_listner from this tutorial and switched the names of the links.

Yes, but which links. Names are important here.

I made some slight modifications to the bringup file

please mention which changes.

And also please tell us what doesn't work. What sort of errors do you see?

I can see this when i echo the tf topic

what do you see? What do you expect to see? Which transforms are missing?

gvdhoorn gravatar image gvdhoorn  ( 2020-02-10 03:24:51 -0500 )edit

We'll probably need to see how you added your EEF and "table links" to the URDF/Xacro.

ur_robot_driver uses a specific version of ur_description (and related packages) and it could be your modifications are no longer being loaded after you switched.

gvdhoorn gravatar image gvdhoorn  ( 2020-02-12 03:35:18 -0500 )edit

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answered 2020-02-26 08:57:01 -0500

stefvanlierop gravatar image

updated 2020-02-26 08:57:26 -0500

The reason why the other links did not show up in the rqt_tf_tree was because i was only using the robot description of the ur10 and not the description of the entire robot. so this question can be closed as there is no issue.

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Asked: 2020-02-10 01:24:11 -0500

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Last updated: Feb 26