All Questions
45,262
questions
0
votes
1
answer
10
views
What is the difference between callback_group and callback_event when creating a publisher?
The documentation of the Node class defines the create_publisher function as follows:
...
0
votes
1
answer
10
views
MoveIt collision checking: when is contact stored vs. not stored
(ROS version is Melodic)
I'm using PlanningScene::checkCollision() to check for collisions, and noticed that when there are multiple collisions -- as in more than 1 ...
0
votes
1
answer
5
views
how to creating fake Pose
Hello, I am trying to pubuilsh a fake pose in code.
I checked the message rules and put the desired value and executed it, but the following error occurs in the subscriber.
May i know what mistake i ...
0
votes
1
answer
14
views
Understanding JointTrajectoryController of ros_control
Hi,
currently, I am trying to understand how the hardware_interface and ros_control work: velocity_controllers/JointTrajectoryController is chosen for the ...
0
votes
1
answer
4
views
Is there a ros1 package like demo_nodes_cpp from ros2?
I just need a simple talker/listener pair to use for demo purposes. Yes I could roll my own, but for testing connectivity a standard package is a little easier.
Originally posted by rkent on ROS ...
0
votes
0
answers
238
views
How to calculate the workspace of a five bar planar parallel robotic manipulator using MATLAB?
I am trying to calculate the workspace of a five bar planar parallel manipulator using MATLAB. Also, I am trying to plot the exact workspace as shown( kindly check the link). For this I guess I need ...
0
votes
1
answer
18
views
LIDAR sensing backwards
Using RPLIDAR A1M8 on ROS2, navigation 2. I am getting very buggy and odd movement and then during SLAM testing I realized that it is detecting backwards.
I put my hand in front of the robot/LIDAR and ...
0
votes
1
answer
15
views
How to use --headless-rendering on Fortress
I ran this line, ign gazebo -r models/sdf/freenove_smart_car.sdf --headless-rendering and ...
0
votes
1
answer
21
views
KDL problem with cmake after complete removal
I have removed all the orocos-kdl files from ubuntu by sudo rm -rf $ (locate orocos-kdl),
then I have followed the installation instructions and installed orocos-...
0
votes
1
answer
7
views
ResizeNode subscribes and publishes camera info on the same topic
Seems like a dumb question, but I can't find the answer.
I see that image_proc::ResizeNode subscribes to /camera_info, and then generates a new CameraInfo message with the scaled intrinsics. But it ...
0
votes
1
answer
151
views
How to install ROS2 on Ubuntu 20.04 with WSL?
Hello,
I am running on windows 10 and I have installed Ubuntu 20.04 through the WSL environment. Now I want to install ROS2 on the Ubuntu. Which of the two processes should I follow?
Install ROS2 for ...
0
votes
1
answer
5
views
map / navigate on a different axis / plane
Hello everyone,
first of all I would like to thank you for such a great forum, it has helped me solve many issues in the past!
I have questions that could be caused by my luck of understanding how the ...
0
votes
1
answer
10
views
PWM control (Rosbot 2.0)
Hi, I'd like to know how to control the PWM signal directly.
The motor is controlled by cmd_vel by using ros node but how to control the PWM without cmd_vel msg?
Originally posted by choking on ROS ...
0
votes
1
answer
2
views
A nodelet is blocking another nodelet
Hi, I have a package which contains 2 nodelets and I want to run these 2 nodelets in the same manager. The problem is, I can only run 1 nodelets at a time, when I run both of them only the one which ...
4
votes
1
answer
331
views
Does a stable library exist for docking robots using images?
I built a mobile base from scratch, and now I am focused on getting the robot to charge.
The robot is using an on-board webcam (and PC) to detect a QR barcode on the charger unit. Using OpenCV I find ...
0
votes
0
answers
357
views
Outer Position Loop to Control Inner Velocity Loop
I'm trying to control the position of a brushless DC gearmotor. To drive the motor, I have a controller box that provides a velocity that is proportional to a 0 to 5 V input. The motor has it's own ...
0
votes
0
answers
11
views
Real-Time, App-Based Tool Tracking and Inventory Management System
For one of my classes, I need to create a sensor system that can connect with an app that will be able to track when specific tools leave a certain area. I do not know which sensor to implement that ...
0
votes
1
answer
404
views
Derive the system's dynamics function and the Jacobian Matrix G of Extended Kalman Filter of a differential drive robot on a 2D plane
I have found the following answer on the system's dynamics function and what the Jacobian matrix G of the Extended Kalman Filter look like for a 2D robot with a differential drive. Taken from slides ...
0
votes
2
answers
120
views
moveit setup assistant not working
When i launch moveit setup assistant i receive the following error.
...
0
votes
1
answer
15
views
ROS 2 (Foxy Fitzroy) Compatibility with Ubuntu 21.10
Will ros2 (Foxy Fitzroy) work on the latest version of Ubuntu (currently 21.10)? If not, will it be supported in the future? Should I install Ubuntu Focal Fossa (20.04) instead?
Originally posted by ...
0
votes
2
answers
4
views
Multiple Cmakelist.txt
I have a Cmakelist.txt that looks as follows in my project
...
0
votes
1
answer
67
views
prevent teb_local_planner from getting stuck while turning around obstacle (carlike)
I am running teb_local_planner in simulation for a carlike robot.
Quite often I see teb_local_planner getting stuck while trying to turn around an obstacle. I guess this is because during the path ...
0
votes
1
answer
1
view
Way to modify messages in rostopic without tweaking stuffs in ros driver
This is an example sensor message from my robot topic (/base_imu/data):
...
0
votes
1
answer
274
views
Remapping diff drive controller to cmd_vel
Hi!
I'm looking to use nav2 with my current diff drive controller setup. My controller is currently subscribed to the /diff_drive_controller/cmd_vel_unstamped topic, while it appears nav is publishing ...
0
votes
1
answer
117
views
Moveit2 Octomap Setup
I cannot figure out how to get an octomap to show up in moveit2. I can pass a sensors_3d.yaml as parameters to the move_group and without a transform from the camera to the robot and the move group ...
0
votes
1
answer
48
views
Localization using IMU and LiDAR only
I am quite new to particle filters and other localization algorithms. For my project I am using an IMU and 2D LiDAR on a robot for indoor navigation. Is it possible to develop a new (or adapt existing ...
0
votes
0
answers
107
views
Trajectory following of 3-wheel omnidirectional robot
I created a three-wheeled omnidirectional robot on omni-wheels, there is also a program in which I can plot a trajectory when plotting a trajectory, such data are obtained (X, Y, Tangent X, Tangent Y, ...
1
vote
1
answer
63
views
Dynamically-stable Motion Planning for Humanoid Robots
I was reading the classical robotics paper Dynamically-stable Motion Planning for Humanoid Robots and I don't understand why the two trees are swapped in line 7 of figure 5 (page 11). Seems like an ...
1
vote
1
answer
429
views
How to calculate operating torque and holding torque of a slew drive for a manipulator arm?
Hope you are doing good and enjoying your weekend.
I have a question regarding calculation of torque and tilting moment for a slew drive. Slew drive (motorised) will be used at the base of a ...
0
votes
1
answer
18
views
Using xacro for robot description does not work
Hi,
I defined a model using the urdf and everything works fine. However, when I replace one of the links with a macro, the link is not built to form the tree.
the xacro file: links_joints.xacro`
...
0
votes
1
answer
101
views
How much weight can this DC motor carry?
I'm trying to make a RC Car with a total weight around 1kg. It will be 4-wheel drive with differential drive algorithm. The count of motors will be 4 DC motors simply. I have chosen the following ...
0
votes
1
answer
63
views
ROS2 Message generation in python package
Hi, I have a python package with multiple nodes and I need to send a message from one node to another.
Currently the message type is ...
1
vote
1
answer
240
views
What is the noise in this PWM signal?
I'm in the process of calibrating servos while constructing a new hobbyist robot arm. When testing the base rotation servo I noticed some unexpected noise in the PWM signal while the servo is in ...
0
votes
1
answer
8
views
How to use moveit! to push?
Hello,
I wish to use moveit! to command a robot arm to push an object from its current location to another specified location. I'm new to moveit, but I imagine the task may be implemented by ...
0
votes
1
answer
57
views
aruco_ros not detecting marker
Hello, I'm trying to detect a marker using aruco_ros. The launch code for the aruco_ros node:
...
0
votes
1
answer
1
view
Starting a node twice, with differend parameters
Hallo ,
I want to start my node twice, but it shoud have differend parameter for my COM-Path.
Here is my code:
...
0
votes
1
answer
4
views
how to output the OpenCV image out of the callback function?
Hi, I am subscribing a videostream of compressed image and i knew how to convert it into OpenCV image and was able to show it already. But i want to output(like return value) the OpenCV image from the ...
0
votes
1
answer
450
views
What does RR stand for in RR-manipulator?
I have memorized RR-manipulator as having 2 arms from Google images but "arm" isn't spelled with "R". I also noticed that RRR-manipulator has 3 links. Does R stand for revolute?
0
votes
1
answer
13
views
ROS2 generating 'core' file on error, how to disable?
I'm running a simple talker/listener demo, using a Docker image based on ros:galactic-ros-core w/ros-galactic-desktop installed. I'm getting an error about half the time when I run the demo, but my ...
0
votes
1
answer
157
views
Better Aruco detection
Hello, I'm using aruco detection to detect a marker at the back of a robot, I'm running simulations in Gazebo and checking the camera feed through Rviz. The problem I'm having is that the detection is ...
0
votes
1
answer
5
views
The transition/difference between Citadel and Fortess
Hi there!
I wanted to test my current file on Fortress but it seems that there's few ign syntax are not supported on Fortress from Citadel.
Is there any doc about this?
Originally posted by ...
0
votes
1
answer
1
view
Unable to publish a message to a predefined topic
Hello,
My project is on Linux.
I am having an issue with Publisher. I git clone a package in which a node called A1 has a topic named a1. I also installed another package in which a node called B2 has ...
0
votes
1
answer
69
views
Convert Time Stamp from rosbag(Topic) to Understandable Format Y/M/D H:M:S
Hi someone would you know what the following TimeStamp means? and how to convert it to seconds or other understable format such year/month/day Hour:Minutes:Seconds?
I have a car-robot that has driven ...
1
vote
0
answers
43
views
Help prove the following identity (Jacobian)
I have encountered the following identity expression. Can please someone elaborate and explain how this equation is manipulated?
0
votes
1
answer
17
views
ROS2 plugin does not load for clang-tidy
I have a MoveIt2 PR that creates a new plugin. It's working great except CI does not pass for galactic. Strangely, CI does pass for ...
0
votes
1
answer
49
views
rospy.Time.now() sometimes returns 0
Hello, I'm trying to run this code:
...
0
votes
1
answer
25
views
teb_local_planner keeps selecting impossible trajectories for a carlike robot
I am testing teb_local_planner for a carlike vehicle.
I am trying to make the robot park backward, for which I would expect the planner to turn in 2-3 times (as a human driver would). However the ...
0
votes
1
answer
14
views
Global planner with curvature limit
Hi all,
I'm looking for a global path planner (base_global_planner) with a feature of limiting the curvature (or turning radius) of the path.
I found teb_local_planner which can configure the minimum ...
0
votes
1
answer
232
views
Multiplication of rotation matrix help
I'm Watching Angela Sodemann video on 6DOF robots and am following her example, but I'm getting a different answer for my R3_6 matrix and I'm not sure where I'm going wrong. She uses this as her ...
0
votes
1
answer
63
views
using asio in a ros2 package
I am looking for a sanity check on this idea from more experienced developers.
ros2 is installed on an Nnvidia TX1 using a docker container of the ros galactic release. The container runs a c++ ros2 ...