what is the function of slam2d

[Masoumeh]

hi mattieu,

what does SLAM2d is? and what does it do?
In https://github.com/introlab/rtabmap_ros/blob/master/launch/demo/demo_husky.launch, number 4.

         4) 3DoF mapping with 3D LiDAR
            $ roslaunch rtabmap_ros demo_husky.launch lidar3d:=true slam2d:=true
you mentioned this setting, but when i activate it, i have a lot of jerky movement in the velodyne_points in rviz. it is not matched with the 2d map!

I want to know more about it
thanks

[Masoumeh]

hi mattieu,

would you please help me to understand what does this parameter do??

[matlabbe]

When you set slam2d:=true for this launch file, it sets "--Reg/Force3DoF" to true:

$ rtabmap --params | grep Reg/Force3DoF
Param: Reg/Force3DoF = "false"   [Force 3 degrees-of-freedom transform (3Dof: x,y and yaw). Parameters z, roll and pitch will be set to 0.]

On graph optimization, we only optimize x,y,yaw parameters.

[Masoumeh]

Dear Mattieu,
when i activate slam2d, in Rviz i can see that the robot is start moving a lot. why?
totally, when is it better to activate slam2d?
I am using rtabmap as map provider and 2 instances of robot-localization package. I want to do navigation based on gps.

thanks

[matlabbe]

A video of the issue could help to see the problem. slam2d enables 3DoF optimization, input odometry poses should also be 3DoF to work.

[Masoumeh]

Dear Mattieu, I have uploaded into youtube:
https://www.youtube.com/watch?v=NoCABfVNqRc

thanks

[matlabbe]

Hi,

Do you have more than one odometry? It is like there are multiple nodes publishing on same TF. Is icp_odometry using guess_frame_id? I would check if the input guess is valid first.

[Masoumeh]

when i activate icp-odometry, guess_frame_id is also activated.

 it is the setting that hase been defined in https://github.com/introlab/rtabmap_ros/blob/master/launch/demo/demo_husky.launch

in the main launch file (https://github.com/introlab/rtabmap_ros/blob/master/launch/rtabmap.launch) it has been set:
param name="guess_frame_id"    type="string" value="$(arg odom_guess_frame_id)"

and when i activate icp_odometry, guess_fame_id is activated as well, because:
(pay attention to the second line in the following part)
 
    <arg if="$(arg icp_odometry)" name="icp_odometry" value="true" />
    <arg if="$(arg icp_odometry)" name="odom_guess_frame_id" value="odom" />
    <arg if="$(arg icp_odometry)" name="vo_frame_id" value="icp_odom" />
    <arg unless="$(arg slam2d)"   name="wait_imu_to_init" value="true" />
    <arg if="$(arg lidar3d)"      name="odom_args" value="--Icp/CorrespondenceRatio 0.01"/>

How can i identify that two topics are publishing the same thing??

Thanks a lot

[Masoumeh]

Dear Mattiue,
again I have this problem:
https://www.youtube.com/watch?v=M1KqZTKvekI

would you please guide me what to do? how can i fix it?
Note:
I have used rtabmap as map provider, and two instances of robot-localization pkg. I have merged /rtabmap/odom and /rtabmap/localization_pose with the global odometry information, for the case that gps is not available, it moves based on rtabmap. I have 3d lidar, rtk-gps, imu, wheel odometer

kind regards