Add an ability to turn of /map -> /odom transform to use with RTABMAP

[ArkadiuszNiemiec]

I have found an issue that makes ZED-M not able to work with RTAB-Map while using ZED's odometry and RTAB-Map loop-closure. My goal is to use odometry from ZED and allow RTAB-Map to publish /map -> /odom and correct it when loop-closure is detected.
The problem is that zed-ros-wrapper already publishes /map -> /odom transformation and thus both software overwrites themselves.

To solve it I commented a few lines in zed-ros-wrapper to stop it from publishing this transform. Do you think that we can add a parameter that turns it off? Do you want me to do a PR?

Edit: problem explained on RTAB-Map forum.

[Myzhar]

If you are using the latest updated version from the master branch you can find an example about how to correctly set the wrapper to be used with RTABmap:
https://github.com/stereolabs/zed-ros-wrapper/tree/master/zed_rtabmap_example

Are you using it?

[Myzhar]

Furthermore a parameter to disable map publishing has been added and will be available with the name of publish_map_tf in the update that will be released before the end of the month

https://github.com/stereolabs/zed-ros-wrapper/blob/tutorials_feat/zed_wrapper/launch/zed_camera.launch#L39

[ArkadiuszNiemiec]

@Myzhar Yes but this example is using odometry from RTAB-Map. My goal is to use odometry from ZED and still allow RTAB-Map to correct it on loop-closure.

Edit: Oh, so it looks like the problem is fixed already! I will stick to my modified code until you publish this update. I think we can close this issue.

[Myzhar]

Well, so the parameter I cited in the previous comment is what you are searching for.
Try to checkout the tutorial_feat branch and to set publish_map_tf to false and let me know if that's what you were searching for.
If you have updated to latest SDK v2.6 you will also get the odometry covariance.

[ArkadiuszNiemiec]

@Myzhar I have just tested it. That's exactly what I needed. Thank you.

[ArkadiuszNiemiec]

@Myzhar Unfortunately RTAB-Map crashes with this repo:
[FATAL] (2018-09-21 10:28:55.216) OptimizerG2O.cpp:533::optimize() Condition (optimizer.verifyInformationMatrices()) not me

I have found this topic: RTAB-Map forum in which the author says:

The error is caused by bad covariance set in odometry messages.

Is there a way to turn off covariance? I am trying to debug it further.

Edit: setting spatial_memory parameter to true turns off covariance and also stops RTAB-Map from crashing on loop-closure. I don't know if this is tutorials_feat branch problem so please tell me if I should open a separate issue.

[Myzhar]

Since there is not a loop closure the covariance will always increase if the odom is never reset.
I'm going to add a parameter to disable covariance publishing.
It will be ready in a few minutes

[Myzhar]

@ArkadiuszNiemiec if you get the latest update from the tutorials_feat branch you can find the parameter publish_pose_covariance in the file zed_camera.launch

[ArkadiuszNiemiec]

One more, thank you 😄

[Myzhar]

You're welcome. Thank you too. User feedback are the best way to understand what's missing or wrong 👍