How to prevent Simulink Pacer from resetting ROS time?

Following this tutorial I was able to get co-simulation running: https://it.mathworks.com/help/robotics/examples/perform-co-simulation-between-simulink-and-gazebo.html

There is however a major inconvenience as the Simulink pacer block only allows 2 options on simulation start:

1. Reset Gazebo Simulation time
2. Reset Gazebo Simulation time and state

I would like it to not reset anything at all, as I am working with an elaborate pipeline of ROS nodes which requires time to be monotonic and consistent with Gazebo, used to simulate sensor data.

I have actually already made a fix, by modifying the C++ source code of the Simulink Gazebo Plugin. I simply commented out where the world time is reset and it worked. It would be nice if you were to add it as a a third built in option.

Please let me know if this is not possible and maybe if I shouldn't be doing this at all or there is another way to do it without changing the plugin code.

Thanks,

Bye

Sebastian

AMZ Racing - Driverless Control

[Jakobus Louw]

Thank you so much for this. It helped me a lot. I needed to simulate PX4 with Gazebo and use a Simulink ROS node as a controller.

For those coming accross this same problem, edit the file in your GazeboPlugin folder: GazeboPlugin/src/gazeboserver/GazeboWorldImpl.cpp

Comment out the line in the resetTime() function like this:

void GazeboWorldImpl::resetTime() {
    // return m_world->ResetTime();
}

Then go to the GazeboPlugin/build folder and run

make

to rebuild the plugin.

Answer 1

[Amrtanshu Raj]

Hi,

So the objective of the Gazebo Cosim feature is to design your logic in Simulink and the use Gazebo as a physics engine to simulate your robot. The idea is not to interface Simulink with ROS network but directly to Gazebo.

If you want to use Simulink as a node in a ROS network, you can check out the ROS Toolbox which aims to achieve the functionality you need.

Hope this helps.