bgagnon's profile - activity

Hello,

So for my project I created my own message type and was hoping to have it displayed in RVIZ. It is a slight adaptation of GridCells, but instead of containing a list of Points, it contains a list of a Point message that I created. The custom Point message contains two more pieces of information.

My problem is that the User Guide for RVIZ has told me that there is no API documentation. Is this still true? Is there any way for me to write a plugin? I think using RVIZ to display custom types of messages would make it even more powerful of a tool. Thanks for the help,

Blair

Hello,

Right now I'm playing around with a node which build a GridCells and publishes it. It also broadcasts a transform that says the GridCells are aligned exactly on the map I have.

Then, when the node receives 'odom' data, it adds a cell corresponding to the odom position data to the GridCells.cells list. When I run it in rviz, I want to simply have the path that the turtlebot has taken to be traced out. Everything works great except the odom traced does not line up with the turtlebot and is offset by a few meters.

Where can I get the actual or "corrected" or the position of the robot that the gmapping node thinks it is. Essentially I'm asking how gmapping, or rviz or tf or move_base (not sure which one) knows where the robot is. How is the position of the robot model determined and is that position published?

Thanks for all the help!

Hello,

I was only able to find documentation online for command line tools for throttling or the other topic_tools for that matter.

Is there a way to create a throttle node from a launch file? I want to go from 30hz to something less. Thanks,

Blair

Hello,

When I first started using ROS, I didn't implement it to it's fullest extent and ended up writing code that was already written for me (much better none the less) and now I would like some direction on what I should do so that I don't go down this path again.

I'm working on mapping and navigation and would like to expand the amount of information that is kept in the map message. My current understanding is that, using slam_mapping, a laser scan is converted to a map topic which gets published. This map topic contains MapMetaData and an OccupancyGrid which says what the chances of collision with the robot is in a given spot on the map.

I would like to add more information to the map, for example (not what I'm actually doing, but same deal) storing temperature data as I build the map. I want to use what's already given to me to the fullest and utilize it properly. What should I do?

Currently, this is my best idea: Create my own topic type similar to that of the OccupancyGrid and instead of probability data, it will contain data about the temperature. If this is the way to go, how do I go about creating my own topic type?

All help greatly appreciated!

Blair

Hello,

I've been able to find questions similar to the one, but they all end being resolved in a way that I don't think I can choose.

I'm running ROS Electric on a turtlebot laptop and have another computer running ROS Fuerte. Both are as updated as possible. They are both network properly and can communicate well.

The problem I am having is common, I can't create new packages anywhere because of a permission error. I have no problems on my workstation computer, just the laptop running ROS Electric. Here is the terminal output below after running this command (occurs through ssh or on the laptop itself) from ~/ros_workspace

    robolab@robolab:~/ros_workspace$ roscreate-pkg robonav
Traceback (most recent call last):
  File "/opt/ros/electric/ros/bin/roscreate-pkg", line 35, in <module>
    roscreate.roscreatepkg.roscreatepkg_main()
  File "/opt/ros/electric/ros/tools/roscreate/src/roscreate/roscreatepkg.py", line 125, in roscreatepkg_main
    create_package(package, author_name(), depends, uses_roscpp=uses_roscpp, uses_rospy=uses_rospy)
  File "/opt/ros/electric/ros/tools/roscreate/src/roscreate/roscreatepkg.py", line 63, in create_package
    os.makedirs(p)
  File "/usr/lib/python2.6/os.py", line 157, in makedirs
    mkdir(name, mode)
OSError: [Errno 13] Permission denied: '/home/robolab/ros_workspace/robonav'

I've tried tirelessly to get the package path's set correctly and when I do

echo $ROS_PACKAGE_PATH

it shows this.

/home/robolab/ros_workspace:/opt/ros/electric/share:/opt/ros/electric/stacks

What more must I do to tell ROS where my stuff should go... Keep in mind I don't have rosws since this is electric. Below are the lower contents of my ~/.bashrc file and my setup.sh file.

Bash file

source /opt/ros/electric/setup.bash
export ROS_MASTER_URI=http://192.168.0.214:11311
export ROS_HOSTNAME=192.168.0.214
export ROS_PACKAGE_PATH=~/ros_workspace:/opt/ros/electric/share:/opt/ros/electric/stacks
export ROS_WORKSPACE=~/ros_workspace

setup file

export ROS_ROOT=/opt/ros/electric/ros
export PATH=${ROS_ROOT}/bin:${PATH}
export PYTHONPATH=${ROS_ROOT}/core/roslib/src:${PYTHONPATH}
export ROS_PACKAGE_PATH=~/ros_workspace
export ROS_PACKAGE_PATH=/opt/ros/electric/stacks:${ROS_PACKAGE_PATH}

Hello everyone,

I'm using the latest software for java and rosjava and after searching for a few hours, I couldn't find any api information on how to use rosbag from rosjava. Specifically, writing and reading to and from a bag file. Is this possible?

Any help would be greatly appreciated. Thanks,

Blair