Unable to run RTABMAP ROS on Turtlebot3 using Intel Realsense D435i

[itsthehoneybadger]

Hi, I'm a new user in Github and also still a beginner is ROS. I would like to perform the RTABMAP visual slam using my Turtlebot3 Burger robot using the intel realsense D435i camera.

Hardware spec:

• Raspi 4B
• Ubuntu 20.04 server
• Intel Realsense D435i
• ROS Noetic

I installed the intel realsense using this code: sudo apt-get install ros-$ROS_DISTRO-realsense2-camera
I installed the RTABMAP using this line: sudo apt install ros-$ROS_DISTRO-rtabmap-ros

When I launched the camera, there were some warnings and at the same time when I tried to launch the RTABMAP, it was not able to receive any data from the camera. I will attach some pictures regarding the warnings.

Would highly appreciate some suggestions or help. Many thanks!

Left side is the warning when launching the camera, right side is the error message from the RTABMAP

[MartyG-RealSense]

Hi @itsthehoneybadger The log messages indicate that there is a communication problem where data is not being received.

The RealSense ROS wrapper has IMU topics disabled by default. Please try enabling them with the roslaunch instruction below.

roslaunch realsense2_camera rs_camera.launch enable_accel:=true enable_gyro:=true unite_imu_method:=linear_interpolation

This should publish accel and gyro as a single combined /imu topic.

[itsthehoneybadger]

Hi @MartyG-RealSense , thank you very much for your reply

This is the launch code that I used to run the camera:
roslaunch realsense2_camera rs_camera.launch
align_depth:=true
unite_imu_method:="linear_interpolation"
enable_gyro:=true
enable_accel:=true

This is the launch code that I used to launch the RTABMAP:
roslaunch rtabmap_ros rtabmap.launch
rtabmap_args:="--delete_db_on_start --Optimizer/GravitySigma 0.3"
depth_topic:=/camera/aligned_depth_to_color/image_raw
rgb_topic:=/camera/color/image_raw
camera_info_topic:=/camera/color/camera_info
approx_sync:=false
wait_imu_to_init:=true
imu_topic:=/rtabmap/imu

However, the same problem still persists. The RTABMAP still is not able to receive data from the camera.

[MartyG-RealSense]

It looks as though you have already tried the guide at the link below as your launch procedures for RealSense ROS and rtabmap_ros for D435i are the same as this guide.

http://wiki.ros.org/rtabmap_ros/Tutorials/HandHeldMapping

[itsthehoneybadger]

Hi, so far the RTABMAP is already able to receive data from the camera.

However, when I try to launch the camera, I noticed there is this warning as shown in the picture, regarding the hardware clock

So at first the RTABMAP works fine, but after some time, the RTABMAP stop working with this error message, stating that it doesn't receive the IMU data.

I'm guessing there is something to do with the clock. I've also read several forums, it was mentioned that it has something to do with the global timestamps of the intel realsense.

[MartyG-RealSense]

Yes, some RealSense ROS users have found that disabling global time (which is enabled by default on 400 Series camera models) resolved their IMU problems. This is discussed at IntelRealSense/realsense-ros#1906 (comment)

For some users, a combination of disabling global time AND resetting the camera with initial_reset:=true included in their roslaunch instruction worked for them.