kwiesz91's profile - activity

Is that suppose to be "+ cmd_vel.speed" at the end of the first line instead of just "+ cmd_vel"?

@RB rviz is used to display the static map, not load it. To load it, check out map_server. Also, your question is almost completely unrelated to this question, so you should have posted this as a different question.

I figured, but good point.

I should have just said: "...but then how does this relate to the base_link"

Thank you so much. This is the exact answer i was looking for. Maybe I'm crazy in thinking that the text could be a little clearer? Or maybe it can just blatantly say "the center is where you have your base_link" for people like me.

To attempt an answer (I have yet to actually mess around with navigation, just reading a lot): The costmap is stored in layers (with one of them being the obstacle layer), I believe that you can just get rid of the obstacle layer, if that's what you want.

That question is completely different from the first question; you should post it as a new question. I think the general rules of ROS Answers is to not post follow up questions in the answers.

I would take Progtologist's advice because your question reveals that you have not really done your homework on the subject.

Confused me as well. Sebastion is correct, and it seems the only way that people will know this is by searching ROS Answers.

Just a side note for future observers: the navigation robot setup tutorial states that you should have either "footprint" or "robot_radius" set, not both.

I don't know if it was this way back when you answered this, but the global costmap can handle updating the map. When a new map appears on the map topic, the costmap will re-initialize its map.

Your error is because you are publishing the static transform map_to_odom. The (map -> odom) transformation is what the SLAM or Localization algorithm (e.g. gmapping or amcl, respectively) is in charge of outputting. (map -> odom) is the transform that corrects the drift in your odometry.

Typical transform setup of a mobile robot:

• (base_link -> base_scan): Static transform that relates the scanner's frame to the robot's center of rotation (it's the scanner's pose in the base_link's frame).
• (odom -> base_link): Broadcast by your Odometry node; it's the pose of the robot if just using odometry and is subject to drift over time (typical odometry comes from wheel encoders).
• (map -> odom): Broadcast by SLAM/Localization node, which takes in the output of the odometry node and sensor readings to improve the accuracy of the robot's pose.

It would appear you have a lot of reading to do on transforms. Have you went through relevant tutorials yet? TF tutorials are here, and this is more info on how frames and transforms are typically used on mobile robots.

In the robot setup navigation tutorial, it says:

"In the case of specifying the footprint, the center of the robot is assumed to be at (0.0, 0.0)..."

From this, it sounds like they want it to be the actual center of the robot, but then how does it relate this to the center of rotation, which is used everywhere else? Because in my case, I have static transforms that relate the sensor positions to the center of rotation, not the actual center of the robot.

A side comment: I wish that people/you had properly edited/updated your question because most of the proposed answers make no sense to what the question looks like now. Is there a way to see a timeline for these threads?

Thanks! They must have their package set up slightly wrong or outdated because I ran rosdep install and it said that everything was there.

gmapping is the one where each particle has its own map. DP-SLAM holds a grid of trees.

Actually (in regards to your first point), after a couple frustrating hours, I do not believe that this is implemented in the roscpp client libraries. Check out this issue: https://github.com/ros/ros_comm/issue... . I do not believe they are planning on implementing it either...

Thank you so much! I have been wondering how to do this!

@Gudjohnson I would take a look at the "Writing a tf broadcaster (C++)" tutorial example, here: http://wiki.ros.org/tf/Tutorials/Writ...

Actually, the last parameter in StampedTransform() is the child frame.

http://docs.ros.org/indigo/api/tf/htm...