About the Robotics Questions/Help category

Robotics Questions/Help
#1

General questions/discussion about robotics, including help with ROS, programming, mathematics, etc.
(Please read the guidelines first!)

Guidelines:

  • If your question is about ROS, please consider asking it over at the official ROS Answers page, because that is where the experts are and where other people will be looking for help.
  • There is no guarantee your questions here will be answered, or answered well, it is just a chance for the community to help each other.
  • As with the rest of the forum, please be kind and considerate in discussions.
#2

Hi Josh,

How can I apply torque to a custom robot’s joint. I followed your tutorials and set position publishing to “/set_joint_trajectory” topic but cannot apply torque from my python script. Also, cannot read the applied torque, applied inside Gazebo sim, value subscribing “/joint_states”. How to solve this issue?

Thanks,

Selim

#3

Hello, I have an issue with rviz displaying everything reversed when connected to the actual robot. The physical robot responds correctly to forward and backward , left and right commands using a joystick. In rviz the robot responds to left and right as forward and backward, My camera image is upside down and my lidar scan is also reversed. I am using ROS foxy. I would appreciate some help.

#4

Greetings, I’m trying to follow along with the Articubot series as I design my own bot, but in Humble. Cloning articubot_one from git, I’m able to get everything running from a control standpoint, but the camera and laser topics do not launch when using “launch_robot.launch.py” script. The urdf’s for the camera and lidar load just fine in simulation, just no topics. When I watch the videos in the series, camera and lidar seem to be available in sim from that single launch command.

Question - are those all separate launch files, or does Foxy pull in packages by default that Humble would not?

Only the following topics load with sim:

/clicked_point
/clock
/cmd_vel
/cmd_vel_joy
/cmd_vel_tracker
/diagnostics
/diff_cont/cmd_vel_unstamped
/diff_cont/odom
/diff_cont/transition_event
/dynamic_joint_states
/goal_pose
/initialpose
/joint_broad/transition_event
/joint_states
/joy
/joy/set_feedback
/parameter_events
/performance_metrics
/robot_description
/rosout
/tf
/tf_static

#5

Hi,
I’m trying ro build a robot. Im running ros2 in a docker container in Rpi and in my pc in WSL. I used --network=host when running the docker file and the two systems can ping each other (both connected to the same network)

The problem is when I run ros2 nodes in the two system they do not communicate with each other. For example when I run a talker and listener they do not communicate. I also ran multicast send and receive in the two systems, they cannot communicate with each other. I also set the ROS_DOMAIN_ID of both systems to be same and also RWM_IMPLEMENTATION. Still no luck.

Do you have any solution for this?

#6

I am having trouble getting micro-ros installed on a Raspberry Pi Pico 2. I find all the instructions are for the original Pico, but the generated uf2 doesn’t work on Pico 2.

On one of the videos that Josh created he mentioned he wanted to replace an Arduino with a Pico. I hope that can happen soon (for Pico 2 and Jazzy Jalisco).

Thanks,
John