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2011-11-03 08:26:34 -0500 | marked best answer | What is the origin of the inertia tensor in URDF I imagine that its (1) but I'm unfamiliar with the actual implementation to back that up. |
2011-10-09 03:18:15 -0500 | received badge | ● Popular Question (source) |
2011-10-04 09:14:54 -0500 | asked a question | What is the origin of the inertia tensor in URDF The URDF specifications for a link require that the origin of the inertial frame must be located at the center of gravity of the link. (urdf/XML/link) What is the origin of the 3x3 rotational inertia matrix? Is it
The inertia matrix will be different depending on whether it is calculated with respect to 1 or 2. |
2011-08-12 07:00:22 -0500 | marked best answer | TurtleBot gmapping demo still waiting for map To answer your questions: 1) odom is the odometry topic published by the turtlebot_node. This reports the pose of the TurtleBot base_link. 2) You should not create the odom topic. The turtlebot_node should be publishing it. 3) Run the turtlebot_node. This leads me to ask is your turtlebot_node running??? This is what rosnode info turtlebot_node should return: To answer other questions: 1) As TurtleBots are starting to ship out we're trying to finalize much of the code that has been in development. Recently we move our development to using the turtlebot service by default, this impacted many of the launch files in turtlebot_apps, so yes the launch files did change on monday or tuesday of this week (8/8/2011). We Will most likely continue to do release updates over the next week or so to improve usability for turtlebot users. 2) looking at the documentation for the gmapping and robot_pose_ekf packages we can see that the gmapping package provides the map -> odom transform while robot_pose_ekf package provide the odom_combined -> base_link transform. TF then provides the transforms for all the resulting relations when requested. 3) the robot_pose_ekf package uses an extended Kalman filter to combine the raw odometry data from the robot with the imu data using the covariances provided in the odom and imu messages to result in a more accurate odometry that is called odom_combined. I have also create a video tutorial that gives an overview of how odometry works on the TurtleBot, since it seems to be a popular question for TurtleBot users. You can find it here:http://www.youtube.com/watch?v=S4EkL68uB0c |
2011-08-11 09:38:42 -0500 | received badge | ● Editor (source) |
2011-08-11 02:36:40 -0500 | asked a question | TurtleBot gmapping demo still waiting for map UPDATE: I downloaded an update for the turtlebot code today (AUG 15) and the gmapping demo worked. I noticed that there were changes to the gmapping_demo.launch file. Specifically,
Can someone confirm that these updates were made recently? I literally arrived in the office this morning, installed the update, ran the code and had gmapping working (!). I also have some questions regarding the transform tree for gmapping in general.
PROBLEM: I'm trying to get SLAM (gmapping) working on the turblebot and kinect. The turtlebot is correctly generating "fake" laser scan data. The Kinect is acquiring a point cloud which is being converted into a laser scan. I can see all of this working correctly in rviz. But no map is being published... The "Map" display in rviz is saying "No map received" and the slam_gmapping node is printing "Still waiting on map..." to the terminal. I believed I have a problem with frames and transformations. In the TF display of rviz, there are two frames that are not connected to the turtlebot frame tree: map and odom (map's child). There are no transformations connecting map to any of the frames in the turtlebot frame tree. In the Odometry display of rviz, rivz says "Frame [odom] does not exist." So the odom frame is not created by default as part of the turtlebot frame tree... QUESTIONS:
MORE INFORMATION: Using rostopic to inspect the "odom" topic more closely, I find that odom has no subscribers (other than rviz). So whichever node is supposed to be running and using the odom information doesn't exist in my current configuration. I would like to provide a rxgraph screenshot of my current configuration, but I get this error (more) |