Questions tagged [topic]
The topic tag has no usage guidance.
210
questions
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21
views
Does rclpy supports intraprocess communication?
I wanted to know if rclpy supports intraprocess communication or is there a way to do intraprocess in rclpy with python based libraries?
Thanks,
- 1
0
votes
0
answers
20
views
ROS2: RQT can not get message class for a user defined message
I can build a package used to define interfaces like messages, service and actions. I think everything is fine since I can show them using the usual command
...
- 33
1
vote
3
answers
61
views
ROS2 data exchange over network
I have a question regarding ROS2 data exchange over the network.
Let’s assume, I have two hosts that are running some ros nodes over the same network, using ROS_DOMAIN_ID=0, so I broadcast all topics. ...
0
votes
1
answer
22
views
no new messages for rostopic hz /camera/aligned_depth_to_color/image_raw in ros noetic inside docker
steps to reproduce the problem
In the first terminal type: ...
- 183
0
votes
1
answer
33
views
Ros2, topics still persist after subscribers/publishers go out of scope
I have a map plugin I've made for rqt_gui that I am going to be using to visualize location information from n number of ROVs/autonomous vehicles. So far I am able to find and create subscribers to ...
0
votes
0
answers
25
views
VRX wamv position using ROS2
I need information about the instant position of the wamv (osrf/vrx).
Using ROS1 + Gazebo11 it works in general properly:
...
0
votes
0
answers
45
views
Communication problem of ros2 humble
On the ROS2 humble version, we publish messages using the topic method, and there is a probability that the node subscribing to the topic will not receive the message. This situation usually occurs ...
0
votes
0
answers
42
views
navsat_transform_node imu topic data mapping problem
I ran into the problem of mapping the /imu/data topic of the navsat_transform_node node in the robot_localization package. the node has a very strange behavior - when mapping imu data to the /...
- 1
0
votes
1
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73
views
ros2 topic list doesn't work in sudo mode
Hi all,
I'm using Ubuntu 22.04.1 LTS with Linux 5.10.0-18-rt-amd64, with ros2 humble debian release.
I try to launch ros2_control from sudo terminal, but I can't see the ros2 topics outside ( from ...
dei
0
votes
1
answer
29
views
Processing pointcloud2 using ros node with both publisher and subscriber
I am trying to process a pointcloud2 being generated by the /map topic, which I play from a rosbag file containing the topics /tf, /map, /ssl_slam/trajectory topics. By process, I mean I want to ...
hunterlineage1
0
votes
1
answer
23
views
Subscribing and publishing to the same topic (/map) in a single python ros node
My goal is to process a PointCloud2 and visualize it in RViz. I have rosbag data collected. This rosbag file includes /map, /tf, /ssl_slam/trajectory topics. The /map topic is in the form of ...
hunterlineage1
0
votes
1
answer
39
views
[ROS2 Foxy] Topics sometimes subscribed to and sometimes published to
I have two Nodes who communicate with a Float32 message topic.
The typical sequence of events are:
Node A starts
Node B starts
Node A waits to subscribe to topic T
Node B creates topic T publisher
...
Fubbis
0
votes
1
answer
3
views
ROS2 topic name validation
Is there a way to validate topic names in rclcpp? For ROS1 I was using the validate function defined here.
Is there anything that is equivalent in C++ for ROS2?
...
a.g
0
votes
1
answer
110
views
ROS2 nodes stay alive and keep publishing after shutting down
Hi,
I am currently working with ROS2 Galactic on Ubuntu 20.04.3 LTS (Focal Fossa) on a project of mine.
The problem:
After stopping my launch file and shutting down my computer, the next time I open ...
Brulf
0
votes
1
answer
24
views
ros2 topic pub from launch file
Hello everyone,
Does anyone know if it is possible in ros2 to directly start from launch file a simple node that publishes a message?
In ROS1 it was easily possible like this:
...
Raposa
0
votes
1
answer
17
views
ROS2 Resolve topic names rclcpp
In ros1 cpp I was able to resolve a string containing the topic name to the actual topic name that accounts for remappings using the following block:
...
vinny
0
votes
3
answers
30
views
How to show topics using python in ROS2
Hi, everyone.
Like the title, I want to show topics using python in ROS2.
First I thought use a ros2 topic list command through a ...
ksato-dev
0
votes
1
answer
8
views
how can i save rostopic in array?
Hi guys. I need help.
I want to make nodes that 'subscribe topic - save in array' and 'read array - publish topic'.
(in my case it is geometry_msgs::Pointstamped)
But there are no references and ...
Ray_Shim
0
votes
2
answers
11
views
trajectory_msgs/JointTrajectory Exception :AttributeError: 'str' object has no attribute 'positions'
I wrote a python script to publish a JointTrajectory message. It results in an Exception: AttributeError: 'str' object has no attribute 'positions'.
The python script:
...
GUENNI
0
votes
1
answer
9
views
Read /rosout/msg with seperate Python script
Hello!
I am currently working on a project where I navigate a TurtleBot3 to several positions in a room. The TB3 navigation is triggered by publishing messages to a specific topic (/tb3_hsc/command). ...
anonymous55390
0
votes
1
answer
1
view
Does ROS2 support keyed topic?
Hi everyone,
As stated in the title, does ROS2 have topic with keys? I have been studying ROS2 for few weeks and I have looked around but cannot find anywhere stating about keyed topic in ROS2.
Maybe ...
Sapodilla
0
votes
1
answer
2
views
How can I round /scan topic values?
Hello!
I am student and I really want to send /scan topic values to rtabmapviz. I am using ROS kinetic, /scan is topic created by RPLidarNode. Unfortunately I think that I need rounded values, because ...
tominkoooo
0
votes
2
answers
2
views
When exactly is a connect callback of a publisher called?
Hi all,
I would like to know when precisely the connect_cb is being invoked, specified in
...
CodeFinder
0
votes
1
answer
4
views
Number of TCP connections for a "bidirectional" topic?
Hi all,
I have a (possibly) simple question: assume if I have two nodes A, B that communicate over a topic "/my_topic", i.e., both nodes subscribe and publish to "/my_topic" using ...
CodeFinder
0
votes
1
answer
2
views
In publish raise ROSSerializationException(str(e))
In my package that I created, there are 3 nodes currently. I also generate a custom message which is "AnchorScan".
First node does some stuff and only publishes from ...
elcinerdogan
0
votes
1
answer
1
view
What is the proper convention for published topic names?
Hi, I'm working on a wheeled robot using rosserial and I am publishing wheel encoder counts and velocities. I was wondering if there was a proper way to write the topic names I am publishing. For ...
geistmate
0
votes
1
answer
1
view
How to subcribe both Image topic and Text topic in the same time?
Hi buddy,
I am newbie in ROS. And this is the first time i'm trying to subcribe 2 topics type, 1 for Image topic and 1 for Array of ints topic. And i have a problem on it.
This is my source code:
<...
ToanJunifer
0
votes
1
answer
6
views
How to send Array Message from Arduino to ROS Topic?
Hi Buddy,
I'm newbie in ROS and i trying to send data from arduino to Ros Topic. I have send string and integer type. But in Array type i have a small problem. This is my source code:
...
ToanJunifer
0
votes
3
answers
4
views
How to subcribe 2 image topics with 1 node in same time?
Hi buddy,
My name is Toan. I am a newbie in ROS. Now, i'm using Kinect Camera and trying to subcribe 2 image topics with 1 node. But seem like my code is wrong something. If i try to subcribe 1 node ...
ToanJunifer
0
votes
1
answer
1
view
how to calculate difference of two messages in callback function on same topic
Hi Sir,
I am actually reading my hand pose from a Leap Motion sensor and I want to calculate how much the hand moves in X direction.
My question is how to read the message in callback function(as you ...
stevensu1838
0
votes
2
answers
2
views
How to create a node to share data between different robots
I am trying to build a data structure (cloud system) able to receive and send data and instructions from/to different kind of robots (e.g. drones,turtlebots). My idea is to create a node to which ...
Simone92
0
votes
1
answer
6
views
How to wait a method until a callback finishes?
Hi all,
I'm trying to stop a method until a particular callback is executed, because this method uses data that is updated in the callback, but I don't know how to do this task. I'm using ros kinetic ...
Ivan_Sanchez
0
votes
2
answers
1
view
How many nodes can publish to a single topic?
hello every body. I'm new in Ros and I have a simple question.
How many nodes can publish to a single topic?
thank you.
Originally posted by hamed ghasemi on ROS Answers with karma: 3 on 2018-10-07
...
hamed ghasemi
0
votes
2
answers
18
views
[ROS2] Retrieving QOS settings for a topic
Hi,
since a subscriber can receive a topic message only if its QOS profile is compatible with the QOS profile of the publisher, is there a way to retrieve the DURABILITY and the RELIABILITY settings ...
- 184
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1
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5
views
Message order with multiple publishers to same latched topic
Scenario:
a node A publishes "hello" to a latched topic /x with queue size 1
then a node B publishes "world" to the same latched topic /x with queue size 1
Because of the latched ...
knxa
0
votes
1
answer
5
views
How to check size of a topic on multi device ROS Communication
Hello, experts.
I am trying to ROS communicate with multi device.
There is two PC. First one have a camera sensor, it have publish topics by 30 fps.
Second one have be connected to another by 1Gb ...
harderthan
0
votes
1
answer
4
views
Undefined reference to RosIntrospection functions
Hey guys,
I try to convert the Raw Buffer of a ShapeShifter to its original DataType Structure. But I have Problems understanding the new API. In the wiki the author used functions, which are not ...
Felix394
0
votes
1
answer
1
view
hz of our sensor's the topic was DECREASED, When I record some data with rosbag
Hello, experts.
I used rosbag to acquire our sensor data as camera, lidar.
You can reference below spec.
Camera Node : 1980x1208 (FHD, RGB), 20 hz
Lidar Node : 64 Channel, 20 hz
I recorded topics on ...
harderthan
0
votes
1
answer
5
views
How to increase frequency of /diagnostics topic published by epos_hardware node?
Dear ROS community,
I am using the epos_hardware ROS package as a hardware interface between an effort controller and a EPOS2 motor controller coupled with a Maxon EC90 motor. The set up is working ...
indraneel
0
votes
1
answer
4
views
Fanuc Robot: Get ROS to read I/O pins
More of a general question, but has anyone figured out how to get a readout of any of the digital pins I/O within ros, as some form of a publisher?
Originally posted by nquattro on ROS Answers with ...
nquattro
0
votes
2
answers
13
views
FastRTPS Topic & ROS2 Topic list
Hi, All.
When using the HelloWorld example of the C++ example in ROS2, it appears in the node list, but not in the topic list.
Of course, when node_demos_cpp is used, it appears in the Topic list.
But ...
Kei
0
votes
1
answer
1
view
Why do I get ampersand characters in my strings?
I'm trying to fix an issue that appeared on ROS Melodic, I cannot reproduce this on ROS Kinetic.
In short
I'm using QCheckBox objects and setting the text to a ROS ...
VictorLamoine
0
votes
1
answer
1
view
It was delayed to subscribe a image topic by frame rate of Images
Hello, guys.
I have used ROS Kinetic on ubuntu 16.04.
I make a two node. The one is publisher node to publish image topic.
Another is subscriber node to subscribe publisher's topic.
The transmission ...
harderthan
0
votes
1
answer
6
views
rosbag : rewrite the values of a topic
Dear all,
what can be the best way to rewrite the values of the messages in a topic in a bag file. For instance, how can I go about creating a new bag that contains modified values of a topic of ...
lounis
0
votes
1
answer
4
views
How to make a ROS topic?
How do I make a ROS topic. I want to make a ROS topic (Either a subscriber or a publisher) which I can either write to or read from.
For example: how ROS programs have topics I can subscribe to or ...
sdcguy
0
votes
1
answer
5
views
rosout logging + topic subscription: not thread safe
I believe I have found a threading issue with ros logging.
If a node subscribes to a topic in one thread and logs to rosout in another, a conflict can occur, since the nodes topic list may be altered ...
knxa
0
votes
1
answer
1
view
Reset topic published by plugin while resettin simulation
Hi,
this is a follow-up to this question. Is there a way (in python?) to reset the topic published by force_torque sensor included in urdf, or, for example joint_states topic to base values right ...
Fiddle
0
votes
1
answer
2
views
Controll of urdf on gazebo with ros topics
I've managed to create an urdf file and can simulate it in gazebo. It consists of a 3 finger gripper so the joints are all revolute. Now I want to be able to rotate them on gazebo or rviz, this is, ...
JuanTelo
0
votes
1
answer
7
views
Make gazebo subscribe to a ROS topic?
Hi, I've noticed that there are some ros topics that have the gazebo as a subscriber. Can someone tell me how can I make gazebo subscribe to a topic I create or where I can learn about it?
Originally ...
JuanTelo
0
votes
2
answers
1
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Subscribe to a Gazebo topic and publish in a ROS node
Hi.
My idea is quite simple. Launching the turtlebot3 simulation, I would like to get /LaserScan information from gazebo and use it in a ROS node. Is there any example I can follow? I would like to do ...
polde