Ask Your Question
0

nav2d Navigator failing to create path

asked 2015-10-13 07:07:02 -0600

Swan Baigne gravatar image

updated 2015-10-15 07:25:07 -0600

Hello, I am trying to use nav2d with the turtlebot robot, in order to map an unknown room. I was able to modify the tutorial3.launch file and the costmap is created without problems. But when i try to add a goal in Rviz, the robot don't move and it show

[ERROR]: Prepare failed!

I also tried to use

rosservice call /StartMapping 3

but it only print response: 0 and shut down.

Here is my rqt_graph : http://img11.hostingpics.net/pics/270...

EDIT : The mapper log show the following error

[[33m[ WARN] [1444902817.579649858]: Failed to compute odometry pose, skipping scan ("base_laser_link" passed to lookupTransform argument source_frame does not exist. )^[[0m
edit retag flag offensive close merge delete

1 Answer

Sort by » oldest newest most voted
0

answered 2015-10-14 09:20:35 -0600

Sebastian Kasperski gravatar image

"Prepare" means, that the Navigator tries to get a map and the robot's position from the Mapper. You should check if a map is build (global map from Mapper, not local costmap from the Operator).

edit flag offensive delete link more

Comments

Thanks for your answer, it seems that the Mapper node is not creating the map. It seems that it is because 3 topic it subscribe to are not published : /tf_static , /karto_in and /initialpose. Which node is supposed to publish those 3 topic ?

Swan Baigne gravatar imageSwan Baigne ( 2015-10-15 01:47:47 -0600 )edit

I don't think it is related to these 3 topics. /tf_static is from tf and only used for static transforms, /karto_in and /initialpose are only needed in a multi-robot scenario. You could set the Mapper's log level to debug. And check for errors when you call the get_map service.

Sebastian Kasperski gravatar imageSebastian Kasperski ( 2015-10-15 03:55:50 -0600 )edit

Thanks for your anwers. May i ask how to do that ? i was able to change the Mapper's log level with rosservice call /mapper ros debug, but i don't know how to call the get_map service as it is not listed in rosservice list, only /GetMap/get_loggers and /GetMap/set_logger_level

Swan Baigne gravatar imageSwan Baigne ( 2015-10-15 04:59:08 -0600 )edit

I usually use the 'rqt_console' tool directly to change the log level of a node. There has to be a service 'get_map', which is called by the Navigator in Prepare-Phase. Looks like your mapper is not running correctly. Are there any messages from the mapper during startup?

Sebastian Kasperski gravatar imageSebastian Kasperski ( 2015-10-15 07:50:48 -0600 )edit

No messages during startup, sadly :-( It only show around 20 time a sec the following message in the Mapper log :

[[33m[ WARN] [1444902817.579649858]: Failed to compute odometry pose, skipping scan ("base_laser_link" passed to lookupTransform argument source_frame does not exist. )^[[0m
Swan Baigne gravatar imageSwan Baigne ( 2015-10-15 08:17:13 -0600 )edit

This seems to be the problem. All scans are skipped and not added to the map. Make sure that the parameters "laser_frame", "robot_frame" and "odometry_frame" are set according to your robot setup. You can use "rosrun tf view_frames" to inspect your current frame tree.

Sebastian Kasperski gravatar imageSebastian Kasperski ( 2015-10-15 09:11:52 -0600 )edit

Thanks a lot for the answers, i was able to change the /laser_frame to the correct value. It took me so long because thoses parameters are not listed in the rosparam list /Mapper The map is now correctly created, but as the robot is not responding to goals, i may create another question :)

Swan Baigne gravatar imageSwan Baigne ( 2015-10-16 02:13:57 -0600 )edit

But how to set those three frames "laser_frame", "robot_frame" and "odometry_frame" ? I meet the same problem.

张京林 gravatar image张京林 ( 2015-12-23 03:25:00 -0600 )edit

Your Answer

Please start posting anonymously - your entry will be published after you log in or create a new account.

Add Answer

Question Tools

2 followers

Stats

Asked: 2015-10-13 07:07:02 -0600

Seen: 364 times

Last updated: Oct 15 '15