Communicate using ROS between 2 different MATLAB versions

Hello,

I have been trying to use ROS publish and subscribe blocks for communicating between 2 different versions of MATLAB (R2018a and R2022a) on the same computer (same machine). The thing is, I am trying to run experiments on a hardware system that is compatible with R2018a or lower. However, I want to implement Reinforcement learning on the system. RL toolbox is available from R2019a onwards. Hence, I trained my RL agent using R2022a, and now want to deploy the trained agent on the hardware (which interfaces only through R2018a).

The system models, for the hardware interface and the RL agent are in Simulink. So the below description is for Simulink models in the respective MATLAB versions.

I was planning on using ROS publish blocks in R2018a (hardware compatible version) and corresponding subscribe blocks in R2022a (RL agent trained version), both versions on the same computer (my laptop). I thought this way, I will be able to communicate with the hardware using R2018a and recieve the states from the hardware system, which I can publish on a ROS topic. After this, I wanted the subscribe block in R2022a, to subscribe to that ROS topic and recieve the system states which can then be fed to the RL agent. This RL agent can then give out actions, which I planned to communicate the same way (in reverse manner) to the hardware. However, after a lot of tries and going through multiple solutions, I have not been able to figure this out. Any suggestions or ideas are welcome.

[Jagadeesh Konakalla]

Hi Mohammed Mohiuddin,

I understand your case. But it is not clear for me what is that not working. Are you facing any errors ?

The publisher block in 18a should communicate with 22a subscribe block. Please make sure that both MATLAB sessions are connected to same ROS Master.

Provide me more information on issue that you are observing.

Thanks,

Jagadeesh K.

[Mohammed Mohiuddin]

Hello,

The issue here is that it is not working. The two MATLAB versions are not communicating with each other. They are on the same local computer machine. Yes, I tried to connect them to the same ROS master, but I am not sure it did connect to the same master despite me trying it.

[Jagadeesh Konakalla]

Hi Mohammed,

Can you please share models that you used in 18a and 22a MATLAB ? I will try on my end and let you know.

Thanks,

Jagadeesh K.

[Mohammed Mohiuddin]

I am trying with any sample simulink model and I am facing the issue. I created one basic model that publishes (sin signals) in R2018 and another model in R2022 that subscribes to those signals, and even in that case I am facing the issue.

[Jagadeesh Konakalla]

Hi Mohammed,

I have tried on my end and i do not see any issue with communication. Here is what i followed.

1. I launched the rosinit from 22a release MATLAB.
2. Then i ran the rosinit on 18a MATLAB.
3. Simulated the publisher model in 22a release with inf time as Stop time
4. Simulated the subscriber model in 18b release with inf time as Stop time.
5. I can see that subscriber gets the data published from 22a release MATLAB.

Thanks,

Jagadeesh K

[Mohammed Mohiuddin]

If you don't mind can you please share the models with me, and also let me know of any parameters or settings I need to keep in mind.

Answer 1

[Jagadeesh Konakalla]

Hi Mohammed,

Is the issue resolved on your end ?

In case if the issue is not resolved, Please contact us through the MathWorks Technical Support team for further assitance.

Thanks,

Jagadeesh K.