Skip to content

Latest commit

 

History

History
70 lines (56 loc) · 3.19 KB

custom_msgs_2020b_and_up.md

File metadata and controls

70 lines (56 loc) · 3.19 KB
Raw

Generate custom ROS messages for Matlab version 2020b and up

Off the box, Matlab only supports ROS standard messages and can't handle custom messages. The good news in 2020b is that you don't need an add-on to generate custom ROS messages, rosgenmsg is now part of the ROS toolbox.

To note, rosgenmsg has one rather annoying limitation, it expects a directory that contains directories of ROS packages. So if you clone crtk_msgs in catkin_ws/src you will need to use rosgenmsg on all packages in catkin_ws/src. To avoid this, you need to create a sub-directory in catkin_ws/src and then clone crtk_msgs in said sub-directory (for example ~/catkin_ws/src/crtk/crtk_msgs).

If you're cloning crtk_msgs by hand, you can use:

cd ~/catkin_ws/src
# clone in sub-directory crtk and rename to crtk_msgs
git clone https://github.com/collaborative-robotics/crtk_msgs crtk/crtk_msgs

At that point, you can finally generate the code (running Matlab without sudo):

rosgenmsg('~/catkin_ws/src/crtk')

If you're running into an error re. cmake not being found, see fix below and then come back to this section.

Then follow instructions to use savepath but this would apply to all users on the workstation so you should probably skip that step and read the following section.

Paths

Instead of setting the path for all users, you can use your startup script. To edit the user's startup.m, use:

edit(fullfile(userpath,'startup.m'))

In your startup.m, you can add the addpath commands that you want executed everytime your start Matlab:

% to locate crtk_msgs
addpath('~/catkin_ws/src/crtk/matlab_gen/msggen')
% to locate crtk client
addpath('~/catkin_ws/src/crtk/crtk_matlab_client')
% to locate dvrk code - only for dVRK users
addpath('~/catkin_ws/src/dvrk-ros/dvrk_matlab')

Then quit Matlab, restart it and test using:

which startup
% show message properties
rosmsg('show', 'crtk_msgs/operating_state')
% create a message
m = rosmessage('crtk_msgs/operating_state')

CMake not found

The build process for the custom messages requires CMake and you might get an error message indicating that CMake is not found. This might happen even if CMake is running properly in a shell:

> which cmake
/usr/bin/cmake

The issue is that Matlab sets a different path to load dynamic libraries (.so files) and CMake is found but doesn't load properly. To test this in Matlab, try:

!cmake
cmake: /usr/local/MATLAB/R2020b/bin/glnxa64/libcurl.so.4: no version information available (required by cmake)
cmake: /usr/local/MATLAB/R2020b/sys/os/glnxa64/libstdc++.so.6: version `GLIBCXX_3.4.26' not found (required by cmake)
cmake: /usr/local/MATLAB/R2020b/sys/os/glnxa64/libstdc++.so.6: version `GLIBCXX_3.4.26' not found (required by /usr/lib/x86_64-linux-gnu/libjsoncpp.so.1)

To allow Matlab to load CMake properly and generate your messages, first find your system stdc++.so.6 library using locate libstdc++.so.6. Then define LD_PRELOAD and start Matlab:

export LD_PRELOAD="/usr/lib/x86_64-linux-gnu/libstdc++.so.6"
matlab

Note that you will need to define LD_PRELOAD only to generate the messages. This is not needed afterwards.