Questions tagged [ros]

ROS (Robot Operating System) is a free, open-source robot software framework initially developed by Willow Garage. And now under the maintenance of Open Robotics.

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ROS Webcam Stream Really Slow

I am trying to stream the images from my camera to a VM via ROS. Here is my setup: Raspberry Pi 3B+ with Picamera v2. It is running ROS Noetic with cv_camera_node ...
1 vote
1 answer
156 views

Inverse kinematics in KDL without rotation

I am trying to use KDL to do inverse kinematics. However I am not interested in the orientation of the end effector, but only in the location. Is there a way to specify this in KDL? The function ...
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1 answer
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Multi-Agent simulation causing trouble in Rviz

I'm trying multi-agent simulations using ROSBOT 2.0 by husarion. I'm comfortable with single agent but when it comes to multiple agents I'm able to spawn them and control them independently but the ...
2 votes
1 answer
200 views

What is the Point of Monocular SLAM

I am not a V-SLAM expert yet, but as far as I understand with monocular V-SLAM there is a scale ambiguity introduced by the fact that a camera essentially is an azimuth sensor that maps the 3D world ...
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1 vote
1 answer
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Determining (Heading) Yaw to rotate the Turtle Robot to desired point (X,Y) so it moves towards it

I have a turtle bot and I want to modify its heading so it moves to certain point (x,y) in the world. Now I reckon that yaw is angle from robots reference, how do I determine the yaw as the point (x,y)...
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2 answers
1k views

Tried to advertise a service that is already advertised in this node [/leo/controller_manager/list_controllers]

I'm trying to do a multi agent simulation using leo_rover which is open source. I'm comfortable with single system, but when I add a second robot using namespaces i get the second robot spawned in the ...
0 votes
2 answers
110 views

Where to learn ROS? [closed]

I am trying to learn ROS and so I was looking for some guide or tutorial series. I already managed to set up ROS Kinetic on a Raspberry Pi and ROS Noetic on a Ubuntu VM. I am quite experienced in ...
1 vote
1 answer
405 views

Gazebo freezes on vm after running roscore

I'm a beginner in ROS, since the learning curve for ROS is steep i decided to use a book to learn how to use ros ([ROS Robotics Projects - Second Edition][1]). I'm currently on the third chapter. I'm ...
0 votes
1 answer
892 views

Failed to load plugin libgazebo...: libgazebo...: cannot open shared object file: No such file or directory

When running a command similar to the roslaunch gazebo_ros empty_world.launch of the Tutorial: Using roslaunch to start Gazebo, world files and URDF models, I get ...
1 vote
1 answer
223 views

pid tuning the wheel velocity

I am using diff drive controller to control the wheels of my robot. Here i am trying to use the control toolbox pid class for making the input velocity and velocity measured from wheel encoder to be ...
0 votes
1 answer
215 views

What causes rviz black screen at startup?

I have been running the same rviz conf for months and mostly have had no issues. But lately there is often a black screen at rviz startup and it happens seemingly randomly, without any error messages ...
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1 vote
1 answer
465 views

Hector_navigaton on ROS Melodic error

I'm a newbie on robotics, and currently, I'm working on a project to make an autonomous robot that can mapping the surrounding environment and decide the shortest route towards the goal while avoiding ...
0 votes
1 answer
392 views

How to make two frames relative to each other

I have a Velodyne and camera that both have transformations specified relative to the origin of the robot. The original transformations were specified as yaw, roll, pitch, x, y, z. I wrote a script to ...
0 votes
1 answer
747 views

Is it possible to use ROS2 real-time on a computer and connect to the robot actuator using a CAN bus?

I am using ROS2 real-time (still a lot to learn) to implement the various control element of my robot : SLAM, path planning, controller, etc... For the first step of prototyping we would like to build ...
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0 votes
1 answer
271 views

Solidworks to URDF for robot arm with complex joint's

I've tried to create a URDF model of an arm robot similar to the following links using Solidworks to URDF plugin. This plugin creates a hierarchy relation between joint and links in any robot ...
0 votes
1 answer
394 views

How to add, additional prismatic joint to the end of Universal robot last joint inside URDF file?

Could you please tell me how can I add, additional prismatic joint to the end 6th joint in URDF file of an Universal robot as in the link below: https://github.com/ros-industrial/universal_robot/blob/...
1 vote
2 answers
664 views

To calculate roll,pitch and yaw

How do I calculate roll,pitch and yaw value from the position co ordinates of the drone, that is x,y and z from the gps sensor??? Using the x,y and z co ordinates I have to calculate roll,pitch and ...
0 votes
1 answer
294 views

Error when "catkin_make" is run

I cloned a gazebo ROS package from https://github.com/YugAjmera/omni3ros_pkg and if I try to do catkin_make,I get the following error. I am using Gazebo 11 and ROS Noetic and i've made sure to source ...
2 votes
1 answer
422 views

What's the correct approach to merging of localization and odometry data?

We've got a mobile platform with a source of odometry and an IMU, which are merged in an EKF filter (robot_localization node), producing continuous odom->base_link transform. The robot is also ...
0 votes
1 answer
497 views

ROS Navigation stack with Omni-wheel robot

I have worked through navigation stack on diff-drive, I'm wondering how to get the stack running on 4 wheeled Omni-wheel robot equipped with Arduino and how to get odometry from 4 wheel encoders It ...
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1 answer
301 views

Error in Pose(): All values are zero for turtlesim/Pose

Here is the program I have written. The function is to make the turtlesim complete one revolution, with a fixed angular velocity and speed. ...
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0 votes
0 answers
26 views

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. ...
1 vote
2 answers
1k views

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 ??
1 vote
2 answers
67 views

"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 ...
1 vote
1 answer
475 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? ...
1 vote
3 answers
297 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 ...
2 votes
1 answer
880 views

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 ...
0 votes
1 answer
330 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,...
3 votes
1 answer
815 views

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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2 votes
1 answer
9k views

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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1 vote
1 answer
453 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 ...
0 votes
1 answer
233 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 ...
0 votes
2 answers
1k views

rospack can't find installed package

I installed ros-melodic-navigation with: ...
0 votes
1 answer
1k 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 ...
1 vote
1 answer
177 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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0 votes
2 answers
253 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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0 votes
2 answers
636 views

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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1 vote
1 answer
206 views

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 ...
1 vote
0 answers
147 views

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 <...
0 votes
0 answers
19 views

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 ...
1 vote
2 answers
274 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 <...
0 votes
1 answer
129 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: ...
2 votes
1 answer
67 views

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 ...
0 votes
1 answer
7k views

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. ...
0 votes
2 answers
222 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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0 votes
1 answer
205 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 ...
2 votes
2 answers
3k 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 ...
0 votes
1 answer
360 views

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. ...
1 vote
1 answer
112 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: ...
0 votes
1 answer
119 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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