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Collision Checking using Moveit (python wrapper) for a set of Joint Positions

I have a set of robot joint positions which I found by sweeping through the allowed joint positions with a fixed delta. This gives me about a set of ~2 million joint positions. Now, I want to check ...
robot_collision's user avatar
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13 views

Node initialization blocks with rospy for UR5e Robot Arm

I am having trouble to remotely control the UR5e robot arm using code. I am using ROS Noetic and trying to run test_move.py present in Universal Robots' repository ...
Fernando-iTEAM's user avatar
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1 answer
24 views

ROS node testing (publish/subscribe)

I am struggling with an example integration test for a ROS node (in Python). I have a node that somehow processes input data and outputs some messages based on this: ...
Dmytro Prylipko's user avatar
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0 answers
18 views

Python Multi-Robot ROS 1 environment: defining multiple robots in class form (each with their own ROS node) and accessing their class objects?

I'm interested in building a multi-robot learning environment using a simulator such as Gym for the environment and ROS 1 for handling communication between robots. I'd like to set up my environment ...
tt32440bzsr's user avatar
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1 answer
41 views

where is the beginner_tutorials.srv file in the add_two_ints tutorial?

I am learning ros noetic on the page (https://wiki.ros.org/rospy_tutorials/Tutorials/WritingServiceClient)In the scripts/add_two_ints_server.py file within the beginner_tutorials package, there is a ...
Yongxue Law's user avatar
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1 answer
448 views

rospy.init_node() stuck in loop

I had a problem with initializing a ROS node in python in a larger project. The following minimum reproducible example has the same issue: ...
Kriseiks's user avatar
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1 answer
14 views

Possible wrong ussage of transformPoint method from tf

ROS VERSION: Melodic OS VERSION: Ubuntu 18.04 package tf version: 1.12.1 I'm trying to create a node that processes a PolygonStamped object and transform each point of it to a especified frame_id in ...
ÁngeLoGa's user avatar
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1 vote
0 answers
132 views

Using .pyc files instead .py with roslaunch [closed]

I am working on a docker and using ROS 1 noetic as of now. For certain reasons I do not want to distribute .py files as end user do not need to understand what is inside there. So I am using .pyc ...
aarsht7's user avatar
  • 113
1 vote
1 answer
45 views

ROS1 Custom messages generates strange memory graph pattern when using multiple string types

In ROS1 Noetic, I have the following custom message named Test.msg: int32 did string a string b And I have another custom message TestList.mgs: Test[] testList In ...
Enikő's user avatar
  • 11
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0 answers
23 views

How to publish images of a file.bag on a topic with python?

I'm a beginner with ROS, so i thank you in advance for your answers. I have a file.bag (Video) available and I would like to publish the various frames on a specific topic at defined moments of time ...
oliver's user avatar
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0 answers
34 views

Rospy subscriber calling only one thread

I am using python for programming the scripts in my ROS package, for a project. As part of the project, I need to implement a service client, which also subscribes to a topic. Specifically, the node ...
noobcoder's user avatar
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0 answers
22 views

Issues with asynchronously handling a Subscriber callback

I am trying to create a listener that sends a message through a Discord webhook to my Discord server. The issue that I am encountering at the moment is that I do not know how to create an asynchronous ...
Pogo's user avatar
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0 answers
34 views

Bag File Produced via launch file has 0 duration

I am writing bag file via rosbag. I have implemented a bagwriter class with singleton pattern for writing in bagfile ...
Muhammad Hamza Sajjad Abbasi's user avatar
0 votes
1 answer
132 views

Custom ROS Service Cannot be Imported

I have created a simple custom ROS service for ROS Noetic. My import line is: from fishbot_ros.srv import chess_service, chess_serviceResponse The file structure ...
sheep_skins's user avatar
2 votes
2 answers
69 views

does rospy support rosparam update callbacks?

Using rospy/ROS1, I would like a callback when a certain parameter on the ROS1 parameter ...
user3729611's user avatar
0 votes
1 answer
512 views

How to add a header with timestamp to numpy_msg?

I am using the rospy with numpy tutorial to create a publisher and subscriber that send numpy arrays to listener that uses an ApproximateTimeSynchronizer. However, I receive an error when I try to ...
BeginnersMindTruly's user avatar
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1 answer
23 views

Rospy getNumSubscribers()

In rospy do you have a getNumSubscribers() function for the Publisher? Originally posted by schizzz8 on ROS Answers with karma: 183 on 2023-06-03 Post score: 0
user avatar
0 votes
1 answer
782 views

"ERROR: Unable to communicate with master!" and "Unable to Register with master node"

Hello, I have two computers on a local network. First of them has Ubuntu 18.04 as OS, ROS Melodic installed and connected to the network with an Ethernet cable. The other one has Windows 10 as OS, ...
user avatar
0 votes
1 answer
7 views

rospy and Subscriber/Publisher garbage collection

Do I need to store a reference to rospy subscribers and publishers to avoid these objects to be garbage collected? ...
user avatar
0 votes
1 answer
2 views

How to get consecutive images with 3 seconds delay

Hello, I am trying to read two consecutive images from my rostopic using rospy.Subscriber to compare the orientation between these pictures but using the code below, I found out two images I get are ...
user avatar
0 votes
1 answer
23 views

Raising Exceptions in Subscriber Callbacks

ROS distribution: noetic, rospy I want to raise specific exceptions depending on the data received from the rostopic. However, raising exceptions in the subscriber callback (user_callback) returns a ...
user avatar
0 votes
1 answer
148 views

Using rospy.sleep inside a callback

My understanding is that rospy.sleep() will return control to ROS so that it can schedule any other processes that need a turn, and also waith the designated time before it "returns". I put ...
pitosalas's user avatar
  • 465
0 votes
1 answer
50 views

Should I unregister from Publishers/Subscribers when I terminate a ROS node by exiting the script?

Hi everyone. So my question is pretty much what the title is. Is it good practice or even necessary to unregister from ROS publishers or subscribers I used inside my ROS node before terminating the ...
user avatar
0 votes
1 answer
12 views

Is it possible to publish msg in rospy.on_shutdown

I want to publish message while roscore is closing. I tried to use rospy.on_shutdown but it didn't work. In wiki it says "Messages are not guaranteed to be published." for on_shutdown. I am ...
user avatar
0 votes
1 answer
55 views

How to generate 'format: "32FC1; compressedDepth png"' Image in python from float array?

I think there's an answer that involves converting C++ code (https://github.com/ros-perception/image_transport_plugins/blob/noetic-devel/compressed_depth_image_transport/src/codec.cpp) to python- does ...
Lucas Walter's user avatar
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0 votes
2 answers
57 views

Pycharm 'No module named rospy'

Pycharm IDE doesn't seem to recognize ROS modules (It underlines them and doesn't autocomplete), even though when I run the script, the interpreter does recognize them. I should add that I am opening ...
user avatar
0 votes
1 answer
8 views

[ERROR] : Called wait_for_result when no goal exists

This is terminal output: ...
user avatar
0 votes
1 answer
7 views

Making rosnode_cleanup() not wait for y/n from user

I arrived at rosnode_cleanup() after looking at #q9521 and #q285530. I need to use rosnode.rosnode_cleanup() in my Python script, but it is blocking because it ...
user avatar
0 votes
1 answer
337 views

Wait for subscriber callback to receive message - best practice

Hello, I am wondering what is the best practice in python to wait for a subscribed topic to start publishing, before using its messages in the spin method. An simplified example of what I am doing ...
user avatar
0 votes
1 answer
32 views

Image Subscriber Lags (despite queue_size=1 and buff_size=2**30)

Hi, I have been working on a Python class that will allow me to spawn an object in gazebo, take an image of the object, and then delete that object, for a given number of objects that I provide. I am ...
user avatar
0 votes
1 answer
7 views

Does ROS have anything similar to a "global variable"?

I created a node that subscribes data from 3 other nodes (2 nodes publish data in 30Hz while 1 node publishes in about 10Hz). The node I created uses a transformation matrix(4x4) from the slower node (...
user avatar
0 votes
1 answer
268 views

Reading from topic once using rospy.wait_for_message()

Hi, I want to read a message from a topic once, thus I tried to use wait_for_message() like this: ...
user avatar
0 votes
1 answer
34 views

Recursively get message field names in ROS2

We have the handy rosidl_runtime_py.message_to_csv() method for converting a message to CSV, but is there a similar function that will recursively get the field ...
user avatar
0 votes
1 answer
98 views

vscode: rospy import error

The env I am using is ROS Noetic and VS Code along with Pylance. launching rospy nodes is working fine importing rospy gives a squiggle error in VSCode. Also, python syntax is not being highlighted ...
user avatar
0 votes
1 answer
1 view

Is there a way to subscribe to different topics at the same time in rospy?

I am subscribing to various topics and I wish to print them into a .csv log file, but I am not able to print any one of them outside their own callback function. You can see the code at Click for Code ...
user avatar
0 votes
1 answer
12 views

TypeError: cannot marshal <type 'numpy.uint8'> objects

I am unable to set parameters to the param server using the following code: hsv = cv2.cvtColor(image, cv2.COLOR_BGR2HSV) rospy.set_param("lower_h", hsv[:, :, 0].min()) rospy.set_param("...
user avatar
0 votes
1 answer
29 views

How to correctly return an array of ints from service?

I have the following code: RouteRemainder.srv: --- int64[] route_remainder routes_manager,py: ...
user avatar
0 votes
1 answer
44 views

How to correctly translate a pose along an axis?

I have a pose of my robot base_link in the map frame. I'd like to translate this 0.2 m along ...
user avatar
0 votes
1 answer
40 views

How to remove lag in marker publishing?

I am publishing markers in a subscriber callback so that whenever new data is received on a topic a marker is created. Markers are published and displayed well at first but after a while markers are ...
user avatar
0 votes
1 answer
28 views

Attempting to read Battery % via Mavros

I have a quadcopter running a Pixhawk flight controller. I am also running a RPI 4 companion board, and I have a serious of nodes setup for flight and a number of other operations. One node is my ...
user avatar
0 votes
1 answer
2 views

Error calling Service in rospy

Been trying to call this Service implemented in the following code as such: ...
user avatar
0 votes
2 answers
20 views

publish after processing data from 2 synced subscribers (rospy)

I want to make one node to subscribe 2 topics synchronously, process those data, and publish it. I know that publishing and subscribing data with single node is possible, but have never seen any ...
user avatar
0 votes
1 answer
91 views

Confused about spinOnce and sleep

I want to go a little deeper into the "why" from a technical perspective. Not just you must do this, but why. I've looked at the rospy source code but I am still not sure about the following....
pitosalas's user avatar
  • 465
0 votes
1 answer
46 views

Can't send binary String messages in ROS Noetic via rospy

I have to send binary String messages via the ROS message bus. That worked out perfectly with Python 2.7 and ROS Melodic, but fails with ROS Noetic. Here's some example code (of course I don't just ...
user avatar
0 votes
2 answers
31 views

Minimal working example for RViz marker publishing

Does anyone know of a complete minimal working example to publish a marker that can be visualised in RViz written in Python? ...
user avatar
0 votes
2 answers
71 views

Is there a way to extract specific info or lines from a ROS topic?

echo /joint_states has the following output (shortened). I made a node (using the rospy tutorial) to subscribe to /joint_states and I want the.py script to print() just the position list for use ...
user avatar
0 votes
1 answer
7 views

unable to publish Path waypoints for pure pursuit

These are the initial line of my rospy code: ...
user avatar
0 votes
1 answer
55 views

Get valid frames from `tf2_ros.Buffer` based on `cache_time`

tf2_ros.Buffer offers a cache_time argument in both C++ and Python implementations. C++ doc Python code However, on calling ...
user avatar
0 votes
1 answer
18 views

SyntaxError in tcpros_base (Noetic, RPi, Python)

I am new to ROS and am probably making an obvious mistake. I am running Noetic on Raspberry Pi 4 and it appears to have installed correctly. Specifically, I am trying to build a very simple node (...
user avatar
0 votes
1 answer
44 views

A ROS message that contains no data, Signal only?

Hello all, Newbie here with ROS, and I have to say I love it. Its a lot of fun and I can only imagine the possibilities. With that said. I haven't had any luck finding anything of its kind, but does ...
user avatar

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