Zed-ros-wrapper: How to turn off the ZED odom?

[stevemartinov]

Hi,

How can I completely turn off the odom produced by zed_wrapper_node?

[Myzhar]

Hi @stevemartinov
the question requires more information:

• do you want to turn off Positional Tracking module or do you want to stop the publishing of the "odom" topic?
• do you want to turn off the topics or the TF publishing?

[stevemartinov]

I just want to stop publishing the Odom topic

[Myzhar]

Simply do not subscribe it. All the topics are published only if there is at least a subscriber

[stevemartinov]

But I can't, I need "odom" topic as I am producing it from my encoders and zed publishing to the same topic

[Myzhar]

ZED publishes the same message, but the topic is different. I'm pretty sure that the encoder puslishes something different from /zed/odom.

Are you sure that you are not speaking about TF?

[abylikhsanov]

@stevemartinov
There is a parameter called "odometry_topic", just set it to any other name:

<param name="odometry_topic" type="string" value="zed_odom"/>

[abylikhsanov]

@Myzhar The default launch file publishes the odometry to odom, here:
https://github.com/stereolabs/zed-ros-wrapper/blob/111725ad1487c1aef387f5ec767e687581c0b7bc/zed_wrapper/launch/zed_camera.launch#L140

[stevemartinov]

@abylikhsanov
Thanks, that helped.

[Myzhar]

The scope of that parameter is exactly that.
However the ZED node (unless you changed the launch file) runs in the zed namespace.
Namespaces in ROS are used to be sure that topic name doesn't conflict.
In your case if you publish a /odom topic, you can publish also a /zed/odom topic (without changing the topic name) and you will not have any kind of conflict

[stevemartinov]

@Myzhar Yes I know but the default launch file does not appear to group the node with a namespace

[Myzhar]

Are you using the latest master version?

The zed.launch file starts the ZED node in the zed namespace:
https://github.com/stereolabs/zed-ros-wrapper/blob/master/zed_wrapper/launch/zed.launch#L38

[milan-r-shah]

Hi @stevemartinov
the question requires more information:

• do you want to turn off Positional Tracking module or do you want to stop the publishing of the "odom" topic?
• do you want to turn off the topics or the TF publishing?

Hi,
Could you please tell me how can I turn off TF publishing?

I'm using ZED camera with TurtleBot2 and now I'm too much confused between 'odom' & 'map' topics of ZED camera as well as those of TurtleBot2.
I'm also confused for 'odom' and 'map' in tf_tree. Currently, in my tf_tree, map (of ZED) is linked to odom (of ZED). But I want them to be connected through TurtleBot2 not ZED.

In RViz, I think because of this only, TurtleBot2 is tilted; sometimes its half portion is in the ground or sometimes it's completely in the air!!)

Thank you

[Myzhar]

Hi @milan-r-shah
the ZED TF tree respects the ROS specifications, to get more details about map, odom and their meanings you can read the REP105 official documentation that "specifies naming conventions and semantic meaning for coordinate frames of mobile platforms used with ROS."

[milan-r-shah]

Hi @Myzhar
Thanks a lot for the quick response and sharing the link of REP105. It was quite helpful.

For those who are also facing this problem, there are two (or at least, that's what I know of) ways to resolve that:

1. If the wrapper is being launched by _zed.launch_ file then it uses one of the parameters files, called _common.yaml_. In that file, there are two parameters:
   
   
   
   • publish_tf (publishes TF between odom and base_link)
   
   
   • publish_map_tf (publishes TF between map and odom)
     
     By default, their values are _true_. Upon changing them to _false_, I was able to resolve the problem.
   
   
2. Another quick solution is to use _zed_no_tf.launch_ file rather than zed.launch. As its name suggests, it doesn’t publish those 2 TFs and so no need to modify the parameter file.

@Myzhar or anyone else, please correct me if I'm mistaken here.

Thank you!

[Myzhar]

That's correct.
Please close the issue if you think it's solved.

Don't hesitate to open new issues if you need further help

[milan-r-shah]

@Myzhar thanks for such quick response. I appreciate that.
By the way, I didn't create any new issue. I think I just commented in one of the existing 'closed' issues. So, to confirm, I don't have to do anything now, right?