Morefoam's profile - activity

Hello I am very new to ROS. I did most of the tutorials but have some questions still. This question: Is a catkin package a node?

More in-depth: So I have my catkin workspace and within that workspace I can have multiple packages. Is each package supposed to be a node? or are there multiple nodes within one package? I guess I'm asking what is the standard layout of the catkin workspace? Sorry for such a primitive question and thanks for the help! :)

Hello, I am using the turtlebot simulator in gazebo and I want to get its pointcloud data and send it in real time to a mapping program (gmapping maybe?). Where can I find the pointcloud data?

Hello, I'm new to ROS (did the basic/intermediate tutorials) and want to try and map pointcloud data.

My question: How do I generate pointcloud data (preferably without an actual camera/robot - a simulation) and map it (using rviz?)?

My thought process on the steps to do so (this is what I think I need to do - could be wrong):

1.) Create catkin workspace

2.) Create 3 nodes in my package (point cloud generating node, mapping node, display node)

3.) Send pcl data (Once generated) to mapping node (and map it somehow), then mapping data to display node (and display it somehow)

If you know of any good tutorials on how to do this, please link them. Or give me your own tips/guide.

Additional info:

• I have my catkin workspace set up

• I downloaded the sample bag file from http://wiki.ros.org/slam_gmapping/Tutorials/MappingFromLoggedData#download and tried to display it on rviz to no success

• Now I'm here :)

Thanks for the help in advance!

I'm not sure if this is directly related to ROS, but I heard the term "general robotics feedback loop" and I tried to do some googling to figure out what exactly this is, but to no avail. Could someone explain to me what this is?

Here are the links I was looking at, but I'm not sure if I'm looking at the right stuff:

https://www.clear.rice.edu/elec201/Book/control.html#SECTION001712000000000000000

http://www.cs.cmu.edu/~./ModProb/MRsol1.html

New to ROS. Can someone give me a VERY simple explanation of gmapping and its algorithm (how it works)? Just trying to get an extremely basic grasp of how it works.

Here are some links I looked at to try and understand it more:

http://www.openslam.org/gmapping.html

http://people.eecs.berkeley.edu/~pabbeel/cs287-fa11/slides/gmapping.pdf

I figured it out. Thanks for the help. I have another question, though. Is there a way to make the bag file save to a specified folder? How do I change "<node pkg="rosbag" type="record" name="recorder" output="screen" args="-a"/>" to make it save to a specified location?

Thanks for the help! How do you go about setting up aliases? I'm pretty new to ROS/Ubuntu, so not sure if I'll be working on multiple workspaces at once any time soon, but it would be nice to know for the future. :)

Hello, I would like to be able to open a terminal and type roslaunch <filename>.launch OR roslaunch <packagename> <filename>.launch and have it launch. Currently I have to cd into my catkin workspace and do "source devel/setup.bash" EVERY time I open a new terminal. How can I make it launch without having to do this every time? Thanks in advance for the help.

Hello, I am new to ROS and the launch file syntax is scary. I want to launch all of these together:

-roslaunch turtlebot_gazebo turtlebot_world.launch

-roslaunch turtlebot_gazebo gmapping_demo.launch

-roslaunch turtlebot_rviz_launchers view_robot.launch

-roslaunch turtlebot_teleop keyboard_t...

-rosbag record -a

My question is: Can a launch file do this? or how would i go about making this executable by typing in "roslaunch <filename>.launch" into a terminal?