ROS2 Basic Python - UNIT3- Not publishing /cmd_vel

[gui.d]

Hello,
I submitted my work to the bot, and it doesn’t like it. I have no idea what’s wrong. The robot does complete the sequence as indicated. I followed the specifications.

Could someone take a look ? Thank you

topics_quiz_node.py

# scrubbed

topics_quiz.launch.py

from launch import LaunchDescription
from launch_ros.actions import Node

def generate_launch_description():
    return LaunchDescription([
        Node(
            package='topics_quiz',
            executable='topics_quiz_node',
            output='screen'),
    ])

[bayodesegun]

@gui.d
Taking a look …brb.

[bayodesegun]

It seems we can’t find your node in the list of publishers to /cmd_vel. Launch your quiz locally, and paste here the output of

ros2 topic info /cmd_vel -v

[gui.d]

Hi, thank you for your feedback.
I launch the quiz in one webshell, and did the command on a second webshell.
Here is the output of the command:

user:~$ ros2 topic info /cmd_vel -v
Type: geometry_msgs/msg/Twist

Publisher count: 1

Node name: topics_quiz_node
Node namespace: /
Topic type: geometry_msgs/msg/Twist
Endpoint type: PUBLISHER
GID: 01.0f.4c.04.2f.33.81.e1.01.00.00.00.00.00.12.03.00.00.00.00.00.00.00.00
QoS profile:
  Reliability: RELIABLE
  History (Depth): UNKNOWN
  Durability: VOLATILE
  Lifespan: Infinite
  Deadline: Infinite
  Liveliness: AUTOMATIC
  Liveliness lease duration: Infinite

Subscription count: 1

Node name: turtlebot3_diff_drive
Node namespace: /
Topic type: geometry_msgs/msg/Twist
Endpoint type: SUBSCRIPTION
GID: 01.0f.7e.8d.1c.01.61.7b.01.00.00.00.00.00.65.04.00.00.00.00.00.00.00.00
QoS profile:
  Reliability: RELIABLE
  History (Depth): UNKNOWN
  Durability: VOLATILE
  Lifespan: Infinite
  Deadline: Infinite
  Liveliness: AUTOMATIC
  Liveliness lease duration: Infinite

[bayodesegun]

Okay, it looks like we should find your node here. Let me adjust something and get back to you shortly.

[bayodesegun]

Please try submitting again now. I’ve added a more fool-proof way of checking that a node is publishing to a topic.

I have also added one more trial for you.

[gui.d]

[Problem solved]

Thank you for your help and fast response !