The ROS Transform System (TF) | Getting Ready to Build Robots with ROS #6

These are excellent. Running Humble on Ubuntu 22.04 Jammy and everything has gone quite well. But I’ve had trouble installing xacro and the joint-state-publisher-gui. Can anyone offer advice on how to do that?

Attempting to run robot_state_publisher I get :
[ERROR] [1705783960.545567604] [rcl]: Failed to parse global arguments
<robot name="robot">
<!-- This is an example of a URDF. -->
<!-- As we move through the file, new things to note will be pointed out. -->
<!-- It's not meant an example of GOOD design, but an example of some of the various features of URDF/xacro. -->
<!-- This file is not a rob, at ./src/rcl/arguments.c:343
[ros2run]: Aborted

I also ran xacro src/urdf_example/description/example_robot.urdf.xacro which printed the xml file to the screen and I don't see anything wrong with it.


I couldn't install foxy so I am using iron.
help.

It works for me so super thank you bro!

Thank you!

If I have a map, and robot inside a map. If I want to get poses of the robot in the map frame, what do I need to write:

1. tf_echo map base_link
2. tf_echo base_link map

These things confuses me, can someone explain to me please?

Awesome! Also- I think Caja is pronounced like “caha”

Everyone finding errors while using this command
ros2 run robot_state_publisher robot_state_publisher --ros-args -p robot_description:="$( xacro ~/example_robot.urdf.xacro )"

Solution
Download file from the github link available in the description.
Extract the file in home directory because we are asking our terminal to look in home directory.

Solved, thanks.

Witch ROS to use

Great tutorials, keep it up!

great video, thanks!

i tried to install ros-foxy-xarco but it kept telling "E:unable to locate packages" i already updated repository and followed intstructions in document before installing packages but not working .Is there any problem? Could you please help ?

ros2 run robot_state_publisher robot_state_publisher --ros-args -p robot_description:="$(xacro path/to/my/xacro/file.urdf.xacro)"



this does not work in my ros i am using ros2 humble how do i run this????

By the way folks, if you watching this on 23/07/23. Which is using Humble ROS. Here some typos updated that might come in handy.

# sudo apt intall ros-humble-xacro ros-humble-joint-state-publisher-gui
# sudo apt intall ros-humble-joint-state-publisher-gui

Also here it is the command to run the URDF file, I had a typo and struggled a bit.
I put the file in the home/user/ folder as it promts its not found in terminal and then enter the command..
# ros2 run robot_state_publisher robot_state_publisher --ros-args -p robot_description:="$( xacro ~/example_robot.urdf.xacro )"

Thank you for the video

Hi , amazing video.
You mentioned that it's painful to type commands for state_publisher and you gave a launch file for that. How do I use it? Should the launch file be put inside the launch folder , then edit the package.xml and colcon build after that?

😁👍

I can’t start dynamic transforms cause I get „no such file or directory: ‚/home/…/example_robot.urdf.xacro‘

Amazing work! Thank u so much for the content! I have one question about robot_state_publisher command. How should i write this with noetic? If i try: rosrun robot_state_publisher robot_state_publisher --ros-args -p robot_description:="$( xacro ~/example_robot.urdf.xarco )" i get the following error: Valid characters are a-z, A-Z, / and in some cases ~. Aborted

Great Series!! , if you can create more content about setting up and exporting URDF from various 3D CAD SW , will be amazing the web is very unclear about that.

Hi, I have a question. I have a Robot with an existing urdf file. Now i want the last axis system to rotate 360 degree. Around the TCP like a screw driver. The last joint can turn about 320 deg in total. So the other Joints need to help. Is there a simple way to fix the axis through the TCP and let the robot rotate around it?

Thanks a thousand for these great ROS videos. Helps me a lot to get back into robotics after having used ros1 back in the days :p

Thank you 👍

I wished I've seen this video 2 years ago when I started learning ROS, it would had saved me a lot of trouble

this ROS2 series is infinitely better than a ROS2 course i paid for on Udemy. wish i found this one first!

I came across your channel and this is by far the best ROS channel. Keep up the good work! Your style is very concise, get to the point and unique. Very potential in the future. I hope that you will have 200-300K subs in the near future.

Do you have any suggestions for how to build a telescopic boom in URDF(typically seen on lifts or cranes)?

So far, this has been the best guide to ROS/ROS2 I have followed. I am looking forward to whatever project lies ahead.

I really believe this is the best explanation out there. Also, love that you are using ROS2. Thanks a lot.

Thank you , This is really informative

Articulated Robotics makes the best ROS2 tutorials in the internet. Thank you very much and I am looking forward for more videos in ROS2. Keep the awesome work!

These videos are pure gold! Thanks for your work

Hi, I find this tutorial really helpful for me, but currently I need to run my program in ros noetic, and I have trouble running robot_state_publisher, is there command for ros1?
Also may I know that if the urdf.xacro works same on both ros1 and ros2 environment?

this is too good! thanks for your work : )

Great tutorial!

Is Xacro necessary to pass as an input to robot_state_publisher parameters? Can't we pass the URDF Directly, if it's already available? I was trying to run the node directly in CLI without using launch file but was unable to do. Then I added the "xacro xmlns ..." line manually in the URDF, treated it like a xacro and it worked. But this seems roundabout. I believe this has to do with the point that the node expects not the path, but rather the entire content.

Hello, so I tried following along with you for the dynamic transforms using robot_state_publisher and the URDF file but I keep getting errors:
"module 'xml' has no attribute 'parsers' and
'ros2: error: unrecognized arguments: --ros-args -p

Edit: Nvm I had a typo. Thanks for the video!

Hi. Why in the tf tree the broadcaster shows "default authority?". I am using foxy and it shows the same too

Your videos are very informative. Keep up the amazing work!

Great video! best explanation ever found.

Thank you so much!

Humble tester :) One of the best ros tranform videos available. Good job sticking the overall goal of transform which is knowing how diffent bodies relate to eachother in space. In some learning resources, It is too eash to get caugh up in the cool math or how cleverly TF works and lose the point of transforms.

Hello actually I'm trying to control my robotic arm using rosserial, I'm using Arduino UNO and PCA 8695 but when I publish joint angles something happens and 0 joint angles are sent in between goal . can u pls help me

A very good, to the point tutorial... kudos!

You're the best at explaining ros.thank you

Informative and well designed vid!

Great video. Great explanation.
Helps a lot with getting into ros.