Sending commands to FCU

[mhkabir]

What would be best way we could implement sending of messages via Mavlink to a connected FCU?

I want to send the VISION_POSITION_ESTIMATE mavlink message, with data from another node.

[vooon]

1. You can send/receive raw Mavlink messages via from/to topics from your node
2. You can write custom plugin (check plugin loader documentation)
3. You can wait some time for 0.4.0 release (general command plugin Command plugin #12 )

[mhkabir]

Can you suggest how I can send/receive raw Mavlink messages via from/to topics ?

[vooon]

See ros_udp.cpp, but additional encode/decode messages.

I want to implement command plugin today.

[mhkabir]

If you implement the command plugin, awesome :D In the meantime I'll check out the source.

[vooon]

CommandPlugin released!

I misunderstood your problem. I thought that this VISION_POSITION_ESTIMATE is value for COMMAND_LONG.command, rather than the message itself. However, the methods 1 and 2 are valid.

I would recommend method 2: coding is easier and less overhead (see dummy.cpp).
Your plugin can be stationed in a separate package (read pluginlib documentation).

[mhkabir]

I finished writing my own plugin. Can you please check if it is OK : http://pastebin.com/WbeSqvMH

Also it would be great if you could give me some simple example code on how to use plugins like Commander from another node. The pluginlib documentation is a bit confusing.

[vooon]

1. Create new package by catkin_creage_pkg
   Example:

   cd ~/ros_ws/src
   catkin_create_pkg mavros_vision mavros
   

2. Create src, srv, msg folders

3. Edit CMakeLists.txt: add messages, servicies, and library for plugin, add this:

   add_definitions(
   -std=c++11
   -DMAVLINK_DIALECT=${MAVLINK_DIALECT}
   )

4. Edit package.xml, add this:
   <mavros plugin="${prefix}/vision_plugins.xml" />

5. Edit vision_plugins.xml, add definition like in mavros_plugins.xml

6. Write code, messages and build via catkin_make in ~/ros_ws

Your plugin with my suggestions: mavros_vision_example_extplugin.tar.xz

[mhkabir]

Thanks a lot for your suggestions. I will build upon what you said.

[BabakAkbari]

Hi @vooon,@mhkabir
I followed @vooon instruction and I was able to successfully build my custom plugin
But I am currently unable to run this plugin
Now I have .so file in my /devel directory
I don't know what to do further?

[vooon]

@BabakAkbari check that you sourced ~/ws/devel/setup.bash after the build.

[BabakAkbari]

After sourcing ~/ws/devel/setup.bash and
Launching mavros I should be able to see my topic I created? Does Mavros automatically find my package and plugin which is located in another workspace? @vooon

[vooon]

It's how http://wiki.ros.org/pluginlib works. пт, 2 авг. 2019 г. в 11:56, BabakAkbari <notifications@github.com>:

…

After sourcing ~/ws/devel/setup.bash and Launching mavros I should be able to see my topic I created? Does Mavros automatically find my package and plugin which is located in another workspace? @vooon <https://github.com/vooon> — You are receiving this because you were mentioned. Reply to this email directly, view it on GitHub <#25?email_source=notifications&email_token=AAHZ4UGWJZRWL4UTKLFHJSDQCPZC7A5CNFSM4AQII2SKYY3PNVWWK3TUL52HS4DFVREXG43VMVBW63LNMVXHJKTDN5WW2ZLOORPWSZGOD3NEFJI#issuecomment-517620389>, or mute the thread <https://github.com/notifications/unsubscribe-auth/AAHZ4UA5OX5HR55DEJ5J2MLQCPZC7ANCNFSM4AQII2SA> .

[BabakAkbari]

Hi @vooon thanks for your response
I ran "rospack plugins --attrib=plugin mavros"
And it returned the name of my plugin but when I launch apm I can't see my plugin's name in the list of plugins mavros shows
Also I ran "rostopic list" and my plugin's topic not shown as well. Am I doing something wrong?

[vooon]

Check that your plugin have same format as present mavros. That issue is quite old, so it describe older plugins.
Also check that you have all necessary macroses called. Check dummy.cpp.