Ask Your Question

Lotoreo's profile - activity

2012-08-20 14:39:08 -0500 received badge  Famous Question (source)
2012-05-14 05:46:23 -0500 received badge  Notable Question (source)
2011-12-18 07:05:27 -0500 received badge  Popular Question (source)
2011-06-17 12:29:28 -0500 marked best answer Ros, stage, gmapping --> tf

I'm not familiar with stage, but gmapping will require your robot (simulator) to publish transforms between the odometry and robot base frames, and between the robot base and laser frames. The default frame names expected by gmapping are "odom" for the odometry frame, "base_link" for the robot base frame, and whichever frame the laser is being published on.

The transform between "odom" and "map" will be then published by gmapping itself.

Check sections 5.1.1 and 5.1.5 in gmapping docs.

2011-06-07 03:30:57 -0500 answered a question Ros, stage, gmapping --> tf

Thx for the links, don't know how I could have overseen section 5.1.5! Now I do at least have a clue, what gmapping needs, and why. But there are still some things that bother me:

1) Do I have to transform the actual values, or is that than by gmapping, if I just give it the right transformation?

2) Do I have to broadcast the transformations or shall I just publish them in the tf topic?

Regards, Lotoreo

2011-06-07 03:20:37 -0500 received badge  Supporter (source)
2011-06-06 21:33:16 -0500 asked a question Ros, stage, gmapping --> tf


I am trying to use ros with stage and gmapping. I can move my robot in stage around, and with rostopic echo I can see, that the sensor readings change. But when I start gmapping, the GridMap values stay at -1.

I guess that is, because I did not compute tf. But rostopic info tells me, that stage is a publisher to tf, so now I am not sure, if I must calculate it myself, or if that is done for me.

If I have to do it myself, i guess i got to do the following:

Create a TransformListener

tf::StampedTransform transform;

listener.lookupTransform("/odom", "/map",ros::Time(0), transform);

And then publish the transform to tf?

Would be really glad if someone could help me!