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How to solve lookup transform problem between frames?

asked 2016-08-16 14:40:01 -0500

Ros User gravatar image

I am using hector_mapping to create map of my room. I used openni node to get the depth/image_raw from kinect sensor, I then changed it to laser scan data using "depthimage_to_laserscan" and used that "scan" topic to create hector_mapping. When I run all of these in a machine it works fine and creates a map but when I run "openni_launch" and "depthimage_to_laserscan" on odroid and "hector_mapping" on my machine, I get an error the following error: "lookupTransform base_link to camera_depth_frame" timed out. Could not transform laser scan into base frame". What does this error mean and how did it not occur when everything was running on same machine.?

My odroid and machine communicates over a wireless network. My machine runs ROS indigo on Ubuntu Trusty.

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Do you have a tf connection between your laser scan and your base frame. A node that publishes that connection to the tf topic ?

patrchri gravatar image patrchri  ( 2016-08-16 15:34:49 -0500 )edit

The easiest way to get what @patrchri describes is to create a URDF file and then use robot_state_publisher and join_state_publisher to publish the transforms automatically.

Mark Rose gravatar image Mark Rose  ( 2016-08-16 15:49:52 -0500 )edit

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answered 2016-08-17 08:55:16 -0500

If you are running on two machines in distributed fashion first be sure that ROS connectivity is fully working. It's important to test both directions, i.e. to make sure publishing and subscribing works. See this Q/A for some info in case it does not.

If ROS connectivity works, the next thing to look out for are time sync issues between both machines. See for instance this Q/A.

Another reason for things not working could be overloading the wireless network (i.e. if you try to transmit too much data).

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Asked: 2016-08-16 14:40:01 -0500

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Last updated: Aug 17 '16