Performance ROS in Simulink

Hello. I launched the "robotROSGetStartedExample.slx" model. I set the simulation time to 20 seconds. On my computer, this very simple model runs for about 6 seconds of real time. To increase the speed, I decided to write an analog of the Publisher block (in the form of an S-function). In its code, in the mdlStart function, I call ros::init. When running the model with the S-function, Matlab returns an error of the "segmentation violation detected" type. Does anyone have any ideas? I use Matlab R2018b, Ubuntu 18.04, ROS Melodic.

[Abhijeet Gadkari]

Hello Mikhail,

There are multiple reasons this may not work.

• Environment setup required to invoke ROS from S-funciton
• Unmet dependencies of S-function on ROS Melodic installation
• Data-conversion between S-function and ROS C++ messages

Try C++ code-generation instead if you want "real-time" execution of the algorithm.

- Abhijeet

[Mikhail]

Hello, Abhijeet. Thanks for your reply. In my post I actually asked two questions: 1) Why do ROS blocks in Simulink work so slowly? If I used UDP data transfer, the execution time of the model was reduced by 1000 times. What is the reason for this behavior? 2) Why I can't write an S-function containing calls to ROS functions? The ros::init function in S-function code is enough for Matlab crashing. It is possible that there is a problem with the boost library (link: https://github.com/lagadic/matlab_ros_bridge). What do you think about it?