Re: rtabmap_drone_example in-depth understanding.

Posted by matlabbe on
URL: http://official-rtab-map-forum.206.s1.nabble.com/rtabmap-drone-example-in-depth-understanding-tp11048p11056.html

Hi MidKnight,

There is no in-depth documentation for the drone example. The rtabmap part is relatively simple though. rtabmap subscribe to imu and image topics, then provide tf map->base_link, which is converted to "vision pose" at 50 Hz for the px4 controller.

1. Have you added an external source of odometry to RTAB? Or, is RTAB's odometry (ie RGBD odometry?) reliable enough?

In that example, we are using default visual odometry from rtabmap. You can however provide your own odometry if not fast enough on your onboard computer.

2. Is there a flow sensor being used with PX4 for a better odometry?

We don't use one in this example, sot not sure how it could be integrated.

3. Is Seeed studio jetson nano adequate for performing autonomous navigation as seen in the chapter 2 of the demo video? If not, what are your suggestions on a) better hardware, b) better performance on the same board with the same setup? Thanks for your response on my previous post and I need some clarification on what your recommendation meant. Did you mean to suggest those VIO methods instead of rtab in localisation mode or does it work within rtab?

Are you referring to this board? When it comes to small computers, the bottleneck is often the acquisition of images from camera that can use a lot of CPU. I don't have experiment on that specific board to be confident to tell you it will work. It can also depend of which camera you are using, is rectification / depth computed onboard the camera or should be computed on the nano? The first makes it easier to integrate. Also don't stream 1080p or 720p, it will be a waste of resources and would make VO running slower, use 360p or lower. When using other VIO approaches, you would only remove the rgbd_odometry or stereo_odometry node from rtabmap launch, but keep rtabmap node for mapping and localization.

4. Is there a ros2 port available? I plan to use ros2 humble with docker on the mentioned board.

yup, see ros2 branch: https://github.com/introlab/rtabmap_ros/tree/ros2 . For some docker usage on ros2: see also https://github.com/introlab/rtabmap_ros/tree/ros2/docker#readme

cheers,
Mathieu