Zeckurbo's profile - activity

Hello,

I want to add two strings together, passed as LaunchConfiguration in my launch file. I have found many answers on that regarding a boolean and to use conditions instead, but is there something simillar to work with the value of the launch description directly in the code? (e.g. use the path to read a file )

EDIT: I found IfCondition(PythonExpression(["'", LaunchConfiguration('test'), "' == 'true']))._predicate_func(LaunchContext)).perform(LaunchContext) Maybe something simmilar can be used to get the real value.

launch_ros.parameter_descriptions.ParameterValue(value, value_type=str) could also be a possible option

Thanks

Hello,

I want to simulate 2 turtlebots with their own slam and navigation together in the same Gazebo ROS2 Foxy simulation. For that, I want to separate them, so that they do not interfere with each other.

I stumbled across this post, but it is not clear to me, what is the best/right way.

As far as I understand, the tf (or tf2) library uses a global name server, to calculate transformations (But could be only in ROS1). When I have both robots publishing a frame with the name odom to /tf, I would expect, tf can no longer tell, which frame belongs to which robot.

I would expect the same behavior for /robot1/tf because of the global name server. So I thought, that the right way would be 1 tree with a frame prefix per robot.

But nav2 seems to use only the namespace, not the prefix. Also here they answered in the same way.

I also cant find any support for frame prefixes in most libraries, they only offer a namespace argument, so I am not sure how to remap their requests for frames.

Does anybody know, how it should be done? Maybe can even explain, how to use it in an example (e.g. Use namespace and remap for every node etc.)?

Thank you very much

EDIT: I think the name recognition is per tf node? So that if I have two /tf in separate name spaces, they will operate fine, right?

Hey Folks!

I've followed this ROS - Tutorial:

https://www.youtube.com/watch?v=8ckSl...

http://moorerobots.com/blog/post/1

But when I want to Launch ROS I get this Errormessage:

enovm@enovm:~/mybot_ws$ roslaunch mybot_gazebo mybot_world.launch 

... logging to /home/enovm/.ros/log/9c283bdc-3614-11eb-a7b1-7d9aeb4bd4d2/roslaunch-enovm-30870.log
Checking log directory for disk usage. This may take a while.
Done checking log file disk usage. Usage is <1GB.

RLException: Invalid <param> tag: Cannot load command parameter [robot_description]: no such command [['/opt/ros/noetic/share/xacro/xacro.py', '/home/enovm/mybot_ws/src/mybot_description/urdf/mybot.xacro']]. 
Param xml is <param name="robot_description" command="$(find xacro)/xacro.py '$(find mybot_description)/urdf/mybot.xacro'"/>
The traceback for the exception was written to the log file

I've also checked if I have installed the newest version of xacro (using sudo apt-get install ros-noetic-xacro) My setup is:

Ubuntu 20.04 on a VM

ROS noetic

Python 3

Gazebo 11

I dont have much experience in ROS, so it is very confusing to me, that even the basic tutorial doesnt work. Thank you in advance!

Hello,

I made some measurements with ros2 topic hz and ros2 topic bw.

I saw, that bw seems to keep on increasing its data source pool forn its measurements (later output has more messages as input) because it prints MB/s from 18 messages, where the number gets bigger over time.

On the other side, when I change the frequency, hz does not instantly increases its rate, but the average only goes up over time, so I was wondering, if hz also just gathers input data and uses all of it for its output, or only 1 window?

Also why is the deviation in s (not in Hz as I would expect it for a rate dev)?

TLDR Is the last output of hz the best estimation, or do I have to calculate the mean from all outputs myself? Is the standard deviation related to the rate? What does it display?

Edit:

I thought about it, and maybe min, max and std dev are for the intervals between messages. So the dev is not the one of the rate, but maybe the one of the intervals? Is there a way to get the dev of the rate directly?

Thanks

I found the code under /opt/ros/foxy/lib/python3.8/site-packages/ros2topic/verb/hz.py In the method get_hz() the calcul

What exactly does ros2 topic hz display Hello, I made some measurements with ros2 topic hz and ros2 topic bw. I saw, t

What exactly does ros2 topic hz display Hello, I made some measurements with ros2 topic hz and ros2 topic bw. I saw, t

Thanks for your answer. What I dont understand is, why is the rate in Hz (1/s) but the std dev is in s (not Hz). Does it

What exactly does ros2 topic hz display Hello, I made some measurements with ros2 topic hz and ros2 topic bw. I saw, t

What exactly does ros2 topic hz display Hello, I made some measurements with ros2 topic hz and ros2 topic bw. I saw, t

I am using this version: https://github.com/introlab/rtabmap_ros/tree/foxy-devel but so far I found nothing specific in

does rtabmap for foxy support multiple threads Hello, I want to use rtab map SLAM with multiple cores to enhance perfor

does rtabmap for foxy support multiple threads Hello, I want to use rtab map SLAM with multiple cores to enhance perfor

Thanks for the answer. I found, that it uses the maximum nr of cores of the PC, no matter how much it gets restricted. I

does rtabmap for foxy support multiple threads Hello, I want to use rtab map SLAM with multiple cores to enhance perfor

does rtabmap for foxy support multiple threads Hello, I want to use rtab map SLAM with multiple cores to enhance perfor

does rtabmap for foxy support multiple threads Hello, I want to use rtab map SLAM with multiple cores to enhance perfor