Unit 4 topic quiz

I’ve tried to solve unit4 topic quiz.
I have a question below description?
Create a Subscriber that reads from the /kobuki/laser/scan topic. This is the topic where the laser publishes its data.

I got this contents that the kobuki robot send laser value to the subscriber node.
But, I have no idea how to run kobuki robot and how the robot can send laser value.
Where is the virtual kobuki robot??? and How can I test this quiz??

Could you let me know my understanding is correct or wrong???

Please let me know the way to move below robot to test test topic_quiz??
I have no idea how can test the topic_quiz???

scrnli_3_30_2024_4-43-12 PM


Hi @sunnypinkpro, all of the simulations you see in the courses have everything you need to perform the quizes.

You can move a simulated mobile robot by publishing velocity messages to the velocity topic the simulated robot offers.

You can check that topic with rostopic list, and it usually is /cmd_vel.

In the node that you created the lidar subscriber, you can also create a publisher that moves the robot depending on the subscriber data.

Hi rodrigo.

I think you got me wrong.
I don’t know basically how to launch the simulation Robot on the browser.
Could I get sample code to move it???

I tried to test example2.1 in our basic class.But the package and launch file don’t exist.
roslaunch turtlebot_teleop keyboard_teleop.launch

So, I have no idea how to run the simulation on the browser window.
That simulation is not “rviz” and “gazebo”. :sob:


Do you understand the previous units? Have you even gone through them?

To move the robot, you need to create a publisher, and then publish “move” commands to the /cmd_vel topic.

To “see” the laser messages, create a subscriber and specify a callback function where the subscriber will send these messages. You can access the messages in the subscriber callback.

The robot? You will use the robot in the simulation.

Thank you for reply.

I solved this issue.
It came out of my environment issue.

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