Questions tagged [ros]

ROS (Robot Operating System) is a free, open-source robot software framework developed by Willow Garage.

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How to use data collect from lidar to generate a 2d map with

I'm new to robotics and I'm using ros noetic with the package rp_lidar. I want to use the data collected from my a1m8 slamteck lidar and generate a 2d map for my rover to navigate and avoid collision. ...
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ROS TURTLESIM using PYTHON

In ROS TURTLESIM, While moving the turtle in circle using the linear velocity and angular velocity , how do i track the distance so as to stop the turtle moving after one revolution ??
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How to list all topics of a remote node

I am new to ROS and have inherited simple code to subscribe and monitor topic on a remote node. The code is using ws4py's WebSocketClient, connecting to ...
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Why can't the Controll Spawner find the expected control_manager ROS interface in a docker container?

I'm using ros-melodic in a docker container based on the osrf/ros:melodic-desktop-full image. What my docker file does: My Dockerfile installs the jackal's robot ...
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system design books for robot software

I see in the realm of app/web dev theres quite a few books out there to detail on system design templates, best practices and concepts. For example senior software engineers are often asked to design ...
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“catkin_make” prompts “+make” and “recipe for target … failed” errors

I have been working on a ground vehicle project for some time that has bunch of sensors, until now I have managed to overcome the problems I have encountered. I have used catkin_make many times and ...
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1answer
91 views

List of tuples as argument in ROS2 launch

I'd like to define an argument in ROS2 launch file which is a list of tuples. How should the list in default_value be formatted? ...
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How does isam compare with Gmapping and Hector?

I read about incremental smoothing and mapping (iSAM) first in the paper on hector_slam (a flexible and scalable SLAM system with full 3D motion estimation by Stefan Kohlbrecher et al) and then read ...
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39 views

No ROS 'sourceing' anymore after installing rosdep2

My ROS-system was working pretty well. Then, I installed rosdep by using sudo apt install python-rosdep2, which ended fine without showing any issues. Then I issued ...
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Running ROS, Gazebo and RViz on Macbook

I have recently started learning robotics. Being at uni, I had access to Linux PCs where I could easily run ROS and Gazebo. However, due to the current pandemic and closure of universities, I now have ...
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89 views

Estimate noise covariance matrix of measurements using a ros-bag

I am facing the following issue, and some hint or orientation would be great. I am working on a project in which I was given a ROS bag, and I have to implement a localization node using SLAM. To do so,...
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UKF for radar implementation

I'm struggling to implement Unscented Kalman Filter for tracking objects using radar. My state vector contains [x y z vx vy vz] and I can measure [rho phi theta velocity]. So everything looks trivial ...
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ROS Laser Scan rotates with the robot in RVIZ

I am currently working on developing a ROS application for autonomous navigation using AMCl. I am first trying to get move_base to work before continuing with AMCL. ...
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RLException: neither a launch file package nor a launch file name

To get straight to the point I want to know how to fix this error and understand it, what is an RLException? Why am I getting this? How can I avoid this later? Below I will post what I did step by ...
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169 views

Get Topic values in script

Hi i am doing an apriltag following project. I am currently trying to test how to get distance between the tag and the camera. I have subscribed to the AprilTagDetectionArray msg. My main question is ...
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1answer
84 views

Custom implementation of robot_localization package

I plan to implement a sensor fusion of IMU + Visual odometry using an EKF. I came across the excellent robot_localization package which does pretty much all that I want. However, I need to use perform ...
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297 views

rospack can't find installed package

I installed ros-melodic-navigation with: ...
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1answer
406 views

Why can't the Controller Spawner find the expected controller_manager ROS interface?

I have a quadruped robot with base link (BL), 4 child links called LFT, LFT, RFT, RFT, T for thigh and each having 4 children with name LFC, LBC, RFC, RBC, C for Calf. 8 joints - Base link to 4 thighs ...
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68 views

ROS2 and TypeError when publishing custom message to Topic

I have defined a custom message: uint8[] data The custom message is imported in my Node class with no problems: ...
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91 views

Can ROS be an alternative for a KFLOP or RUMBA Board?

I have a few questions about controlling robot arm motion. I see that some have used Dynomotion KFLOP and other CNC motion controllers to control arms. Some have used Rumba board as well as several ...
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103 views

OpenCV4.2 and Ubuntu16.04 with python2.7?

Summary: I'm using new vision of opencv, opencv 4.2 with ubuntu 16.04 and python 2.7 After built cv_bridge, the output is: ...
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ROS Network configuration on multiple machines - Publisher and Subsciber

I am trying to set up a simple and listener talker across two machines connected on the same wifi network. Machine A has the 10.42.0.89 address and is running the roscore and another node that ...
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Caculate/Specify the covariance matrix for a omniwheel robot

I have an omnidirectional robot (x, y and rotation around z), which I would like to use the SLAM-algorithm from ROS. But the odometry from the robot has a drift, which makes some error. To improve the ...
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How to setup CLion for ROS remotely?

I know how to set up CMake and Toolchain remotely using ssh through official wiki. Does anyone know how to configure a remote <...
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Why do inverse directions give correct movement?

I am currently working on driving a bot based on the location of a white ball and I find that giving it negative angular movement moves it to the left rather than the right. Here's a code snippet for ...
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71 views

Am I checking for a white pixel correctly?

I am currently going through all the pixels in an image to determine what is a white pixel. I then have to decide where to drive the bot. I am also using sensor_msgs/Image.msg that I get from the <...
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51 views

What are the numbers to the left when logging with ROS_INFO_STREAM?

Here's what I currently see in my terminal when logging: ...
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Syntax highlighting for source code of urdf & sdf (xml-based) files on Github

Note: I posted this on stack overflow but couldn't get an answer. I am trying it here. I have files that are in urdf [Unified Robot Description Format] for ...
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Missing “devel/setup.bash” after “catkin_make”

I'm trying to use ROS and already installed it, but following the tutorial doesn't work for me. When I follow the instructions, create a workspace and run ...
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Simulation flight gives inconsistent sensor data

I made a short outdoors flight of 10 minutes with hector quadrotor on Ubuntu 16.04 Gazebo 7. The sensor readings and the path images are as attached. The flight was simple. I took of slowly, moved ...
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What and where is “the log file” for errors in ROS?

I ran the following and got an error with something that previously ran well (I was just missing the entire world though and not the robot). Something I did in the middle could be the problem. ...
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audio_play dst parameter

I am testing audio_capture and audio_play node on raspberr yp 4B. Here when i tested it by capturing audio on pi and playing in remote computer with audio_play it is playing the audio on my headphone. ...
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99 views

Guidance on SBC for Visual-Based SLAM [closed]

Intro: I am a student that just started a project regarding prototyping a mobile robot that involve Indoor SLAM implementation. I am very new to the field of computer vision, SLAM and SBC (single ...
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64 views

Gazebo throwing error in opening model created in it

I created my world with gazebo9 and saved it. world$ tree . └── myworld ├── model.config └── model.sd Now when I start it with ...
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848 views

Gazebo not reading the material color in URDF

I have a chassis link that has casters. I would like the casters to be grey and the box to be blue. The ROS link doc mentions ...
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Can you refresh gazebo when you load through ROS?

I have a urdf model that I have loaded with: roslaunch my_robot world.launch I noticed that I gave the wrong color to a part of the robot. I have made changes. ...
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1answer
25 views

What is the purpose of an empty link without any child elements?

I was looking at a model xacro [urdf] file in a ROS tutorial when I saw: ...
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1answer
56 views

Coordinates seem to show overlapping but RViz doesn't

How can you place two objects that seem to overlap with their units but appear stacked on top of each other [original intent] in RViz? I was watching this video tutorial on ROS and URDF. I have ...
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1answer
33 views

Why are shapes in ROS and Gazebo called links?

I have been trying to figure out why shapes in ROS are called links, ie <link> tags in urdf and ...
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1answer
34 views

Turtulebot not showing in custom world

I made a map.world file and placed it under /opt/ros/kinetic/share/turtlebot_gazebo/worlds and ran ...
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1answer
148 views

Difference between rosservice and rossrv [the info version at least]

What's the difference? I see my service in rossrv list but not with rosservice list. From ROS wiki • rossrv: displays ...
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2k views

roslaunch not found

Running ROS melodic on Ubuntu 18.04 and I keep getting this error. ...
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1answer
39 views

ROS sensor implementation

From this page, there are lots of sensors to be used in ros robots. http://wiki.ros.org/Sensors But, I could not install any of them to the robots in my simulations. For example, I want to install the ...
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43 views

Data collected from ROS

How can we collect the flight data after a ROS simulation and what kind of dataset do we obtain? Can we get the sensor and video dataset with timestamps to be used in analysis?
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308 views

Path planning algorithm better than RRT* and Artificial Potential Field

Hello robotics stack exchange community, hope my message finds you well during these challenging times. I need an opinion regarding path planning algorithms. Goal I am looking for a path planning ...
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65 views

EKF landmark-based help needed

I am new in localization algorithms and EKF is new for me as well. I think that I implemented EKF (the whole code of class is here. I have problems in updating bearing angle of the robot. Basically I ...
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Monitoring battery voltage for interfacing with UI on QT creator

I want to be able to monitor the voltage of two 12V lead acid batteries in my system, and have the voltage reading to be displayed on a UI designed on QTcreator. One way I've thought of is to ...
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66 views

Planar Robot Boundary Detection

I am tasked with building a robot that needs to localise and navigate itself on a rectangular surface (like a large desk). The rectangle's shorter sides will be marked with a red tape (or with two ...
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62 views

rosrun does not appear to do anything. Node exits immediately

I have a ROS node that seems to exit immediately or not even run at all. I have test print statements before the main loop and it never seems to get to that point. roscore is running and no error ...
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127 views

Controller algorithm implementation in ROS/Gazebo

I am doing some robotic simulations in ROS/Gazebo and wondering what is the best way (programming-wise since I don't have a CS background) to implement a robot's motion controller. Here are the ...

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