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ros-mobile-robots / diffbot

DiffBot is an autonomous 2wd differential drive robot using ROS Noetic on a Raspberry Pi 4 B. With its SLAMTEC Lidar and the ROS Control hardware interface it's capable of navigating in an environment using the ROS Navigation stack and making use of SLAM algorithms to create maps of unknown environments.
https://ros-mobile-robots.com
BSD 3-Clause "New" or "Revised" License
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For frame [rplidar_gpu_laser_link]: Frame [rplidar_gpu_laser_link] does not exist #43

Closed fjp closed 2 years ago

fjp commented 2 years ago

Hello again.

I've successfully got my RPi4 based diffbot driving around using rqt (robot steering) from my development system (Ubuntu on VirtualBox on a Mac). Now I’m trying to move to the next step and enable navigation. I start roscore on the development system and point the diffbot to it and then launch ‘bringup_with_laser.launch’ and everything seems good. I get valid looking data in /diffbot/scan on both systems.

But when I ‘roslaunch diffbot_slam diffbot_slam.launch slam_method:=gmapping’ on the development system I don’t see any lidar data points in rviz I get two errors that I don’t quite know how to interpret:

In rviz:

Transform [sender=unknown_publisher] For frame [rplidar_gpu_laser_link]: Frame [rplidar_gpu_laser_link] does not exist

and in the terminal from which I launched diffbot_slam I get this repeating warning:

[ WARN] [1635345613.864692611]: MessageFilter [target=odom ]: Dropped 100.00% of messages so far. Please turn the [ros.gmapping.message_filter] rosconsole logger to DEBUG for more information.

Any help on why the points don’t seem to be registering in rviz would be appreciated. After a lot of googling this seems to be a TF issue perhaps? I’m a ROS newbie so I must admit I get lost in all the discussions about frames. I did check that the date/time on both systems is correctly synced to ntp.ubuntu.com but I still have the problem.

Regards,

Ian

Originally posted by @joeuser846 in https://github.com/ros-mobile-robots/diffbot/issues/40#issuecomment-953028085

EldarKurbanov commented 2 years ago

I had the same problem. It turned out that on my dev machine I set the ROS_MASTER_URI environment variable pointing to my robot. But I completely forgot to set the environment variable ROS_IP, which should be equal to the IP address of the dev machine on the local network.

I would also check that the ROS_IP variable on the robot is also set correctly.

@joeuser846

fjp commented 2 years ago

Thanks for the hint @EldarKurbanov to check for ROS_IP being set correctly.

Regarding the wrong naming of frames I created commit 60750e9ed2f0ecdb8f6250ca4c396238e8a0447a which should fix the issue. There is now a new rplidar.launch that accepts a frame_id argument which is set to rplidar_laser_link by default. This new launch file is also being used now inside of bringup_with_laser.launch instead of the original rplidar.launch file from the rplidar_ros package, which didn't allow to provide frame_id as an argument.