Hokuyo - No map received in RViz [closed]

asked 2014-08-28 15:17:46 -0500

anamcarvalho
123 ●13 ●15 ●20

updated 2014-09-02 05:22:13 -0500

Hi everyone!

I am trying to use the package "GMapping" to visualize the map acquired with Hokuyo laser scanner!

I have no odometry, so I simulated a TF with a launch file, which worked already in other applications!

<launch>

  <node pkg="tf" type="static_transform_publisher" name="US6" args="0 7 2 1.5708 0 0 base_link laser 100" />

</launch>

When running RViz, in Global Options, the Fixed frame is map; In Grid, the Reference Frame is map; In TF I have the following warnings: No transform from [map] to [base_link] / No transform from [odom] to [base_link] In map, the topic is map and I receive this warning and error message: No map received / No transform from [] to [base_link]

What did I do wrong? I notice that if I change the Fixed Frame in Global Options and the one in Grid, the error disappear and some other errors appear... what are the correct options to be selected in Global Options and in Grid?

Thank you for your time!

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Closed for the following reason the question is answered, right answer was accepted by anamcarvalho
close date 2014-09-02 08:16:52.636418

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answered 2014-09-02 06:19:01 -0500

Malefitz
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updated 2014-09-04 02:07:25 -0500

As bvbdort already mentioned, you need to also publish the base_link -> odom transform. If you don't have an odometry system, you can do it with a static transform publisher in your launch file like this:

<launch>
  <node pkg="tf" type="static_transform_publisher" name="odom_to_base_link" args="0 0 0 0 0 0 odom base_link 100" />
  <node pkg="tf" type="static_transform_publisher" name="US6" args="0 7 2 1.5708 0 0 base_link laser 100" />
</launch>

That way every transform gmapping expects to run is set up. Mind that gmapping won't really be able to extimate the position of the laser in the map, since you publish odometry information manually as a static transformation. But at least you should see a map built from your laser.

PS: If it still doesn't work that way, please provide info about what gmapping prints out.

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Thank you Malefitz, it works =) now I have another question but i'll open a new one, since it isn't related with the transforms!

anamcarvalho ( 2014-09-02 08:16:40 -0500 )edit

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answered 2014-08-29 02:27:23 -0500

bvbdort

3034 ●32 ●43 ●58

For gmapping you also need transform between baselink and odom

Required tf Transforms

<the frame attached to incoming scans> → base_link

usually a fixed value, broadcast periodically by a robot_state_publisher, or a tf static_transform_publisher.

base_link → odom

usually provided by the odometry system (e.g., the driver for the mobile base)

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@bvbdort Since I don't have odometry, the second transform was the one I "simulated".

For the first one, does this exact transform in the tf static_transform_publisher ros page solves? (next comment)

anamcarvalho ( 2014-08-31 10:42:11 -0500 )edit

what do I write in link1_broadcaster, link1_parent and link1?

anamcarvalho ( 2014-08-31 10:42:20 -0500 )edit

base_link --> odom is not static you cant simulate this from static_transform_publisher.

bvbdort ( 2014-08-31 13:32:23 -0500 )edit

But isn't that the one I already simulate?

anamcarvalho ( 2014-08-31 13:53:58 -0500 )edit

static_transform_publisher you showed in question is between laser and base link

bvbdort ( 2014-08-31 15:34:51 -0500 )edit

1

For testing purposes it is ok to publish the odometry with a static publisher. I'll write an answer for it.

Malefitz ( 2014-09-02 04:08:44 -0500 )edit

Thank you @Malefitz, really appreciate it!

anamcarvalho ( 2014-09-02 04:41:21 -0500 )edit

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Hokuyo - No map received in RViz [closed]

Closed for the following reason the question is answered, right answer was accepted by anamcarvalho
close date 2014-09-02 08:16:52.636418

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Hokuyo - No map received in RViz [closed] edit

Closed for the following reason the question is answered, right answer was accepted by anamcarvalho close date 2014-09-02 08:16:52.636418

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Hokuyo - No map received in RViz [closed]

Closed for the following reason the question is answered, right answer was accepted by anamcarvalho
close date 2014-09-02 08:16:52.636418