Hi everyone
I’ve add an actor in a Gazebo simulation. I’ve read that in order to be this actor detected by the sensor I should change the type from <sensor type="ray" to <sensor type="gpu_ray" but I dont find the sensor definition for the turtlebot3 waffle_pi in ros2 galactic. turtlebot3/turtlebot3_description at galactic-devel · ROBOTIS-GIT/turtlebot3 · GitHub
Can anyone help me?
Thanks in advance
Hi @lfernandez ,
I have completed this course Mastering Gazebo Simulator a while back, and I have not come across a term “actor”. Are you working on this course (OR) is this an external request for a problem you have?
What do you mean by “actor”? Are you referring to a model in the world? And by “actor” are you referring to a model of human being?
– Girish
Hi @girishkumar.kannan
It’s not directly related to the course content. I’ve follow this tutorial Gazebo : Tutorial : Make an animated model (actor).
Bu actor they meant an animated model.
Thanks again
Hi @lfernandez ,
I now understood what you meant by “actor” after following your link.
I checked the git repository for turtlebot3 galactic version. When I checked the urdf directory, I could not find any .xacro or .gazebo files. So I guess you should create a .gazebo file and convert .urdf into a .xacro file and later launch the .xacro file instead of .urdf from launch file.
Here is a minimalistic .gazebo file with laser sensor only, let’s call this laser_scan.gazebo:
<?xml version="1.0"?>
<robot>
<!-- Gazebo tags - Laser Scan -->
<gazebo reference="scan_joint">
<preserveFixedJoint>true</preserveFixedJoint>
</gazebo>
<gazebo reference="scan_joint">
<material>Gazebo/DarkGrey</material>
</gazebo>
<!-- Gazebo ROS Plugin - Laser Scan -->
<gazebo reference="base_scan">
<!-- Change Laser Sensor Type Below -->
<sensor type="ray" name="head_hokuyo_sensor">
<pose>0 0 0 0 0 0</pose>
<visualize>true</visualize>
<update_rate>20</update_rate>
<ray>
<scan>
<horizontal>
<samples>720</samples>
<resolution>1</resolution>
<min_angle>-1.570796</min_angle>
<max_angle>1.570796</max_angle>
</horizontal>
</scan>
<range>
<min>0.20</min>
<max>10.0</max>
<resolution>0.01</resolution>
</range>
<noise>
<type>gaussian</type>
<mean>0.0</mean>
<stddev>0.01</stddev>
</noise>
</ray>
<plugin name="gazebo_ros_head_hokuyo_controller" filename="libgazebo_ros_laser.so">
<topicName>/laser/scan</topicName>
<frameName>sensor_laser</frameName>
</plugin>
</sensor>
</gazebo>
</robot>
And here is a minimalistic .xacro file with laser sensor only, lets call this laser_scan.xacro:
<?xml version="1.0" ?>
<!--robot name="robot"-->
<robot name="robot" xmlns:xacro="http://www.ros.org/wiki/xacro">
<xacro:include filename="$(find robot_description)/urdf/laser_scan.gazebo" />
<!-- Laser Scan -->
<joint name="scan_joint" type="fixed">
<origin rpy="0 0 0" xyz="0.8 0 0.3" />
<child link="base_scan" />
<parent link="base_link" />
<joint_properties damping="1.0" friction="1.0" />
</joint>
<link name="base_scan">
<inertial>
<origin xyz="0 0 0" rpy="0 0 0" />
<mass value="0.5" />
<inertia ixx="0.000252666666667" ixy="0" ixz="0" iyy="0.000252666666667" iyz="0" izz="0.0005"/>
</inertial>
<visual>
<origin xyz="0 0 0" rpy="0 0 0" />
<geometry>
<cylinder radius="0.15" length="0.20"/>
</geometry>
<material name="Red">
<color rgba="0.7 0.1 0.1 1" />
</material>
</visual>
<collision>
<origin xyz="0 0 0" rpy="0 0 0"/>
<geometry>
<cylinder radius="0.15" length="0.20"/>
</geometry>
</collision>
</link>
</robot>
The above two files are just an example. You will have to make a copy of the turtlebot3_waffle_pi.urdf and make appropriate changes to include the above two code-snippets.
Note: The above codes are may not work “as-is”. It must be changed to suit the robot model - like dimensions, geometry, collision, visual, etc. Compare the actual values with the original .urdf file and do suitable changes. I have just copy-pasted the code here. It will NOT be correct. This is just to give you an idea of the process.
I hope this helps.
Regards,
Girish
1 Like
Hi @lfernandez ,
If you are still subscribed to the courses, you can take a quick glimpse into Mastering Gazebo Simulator course. This course covers these topics in detail and to-the-point.
Regards,
Girish
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I’ve tried to change the sensor type from the model.sdf turtlebot3_gazebo <sensor name="hls_lfcd_lds" type="gpu_ray"> but actors are not detected.
Thanks again
Hi @lfernandez ,
Where is turtlebot3_gazebo directory located? I cannot find it in the git repository that you have shared in your initial post.
– Girish
It’s inside turtlebot3_simulations. git clone -b galactic-devel GitHub - ROBOTIS-GIT/turtlebot3_simulations: Simulations for TurtleBot3
Thanks again
Hi @lfernandez ,
I think your problem may not be with the “type” of ray. I guess, it has something to do with “visual” and/or “collision” of the model.
I just worked on one of my own ROS package by changing the lidar’s type="ray" with "gpu_ray", and I did not see a major / significant difference in the simulation.
Would you be able to post a screenshot of what is happening in your simulation?
Also, please describe what should be the expected result.
This way I can understand what is happening and (maybe) provide a solution.
Regards,
Girish
Hi @girishkumar.kannan,
the simulation seems to be ok but the actor is not detected in the /scan topic
Thanks again
Hi @lfernandez ,
I am not exactly sure how to fix this problem, I have not faced this issue yet.
For now, I can redirect you to this link: [ROS Q&A] 124 - Range sensor does not detect obstacles in Gazebo - The Construct
Let me know if that link is useful for you.
Regards,
Girish
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