Synchronizer

Overview

Allows a leader process to synchronize with a follower process. The mode (synchronous or asynchronous) can be changed programmatically during runtime.

For exemple, in the follower process:

// running at 200Hz when in async mode
double frequency = 200;

// will have loop running sync or async
synchronizer::Follower synchronizer("synchronizer_id",frequency);

while (running)
{
   // code doing things

   // pulsing instead of sleeping
   synchronizer.pulse();
}

and in the leader process:

synchronizer::Leader leader ("synchronizer_id");

leader.start_sync();
for(int i=0;i<1000;i++)
{
    // code doing thing

    // sleeping to get desired frequency
   usleep(1000); 

    // requesting the follower to run one iteration
    leader.pulse()

}

leader.stop_sync();

The expected behavior:

• when follower is started, it runs at 200Hz
• when leader is started, leader and follower run at same frequency (~ 1Khz)
• when leader exit (calls stop_sync), follower returns at 200Hz

Python

Python bindings are generated via Pybind11. Python/c++ follower/leader processes are compatible one with another (e.g. follower in python, leader in cpp)

Demos

For concrete examples (c++ and python), look at the demos folder. Note that the follower must be started before leader.

Limitation

A follower can be linked to only one leader (at a time), and a leader to one follower.

Installation and compilation

This is an ament package. Recommanded method for cloning is to use treep with configuration treep_machines_in_motion and project "CORE_ROBOTICS"

Licence

BSD-3 clause

Copyright

Max Planck Gesellschaft, University of New York

Author

Vincent Berenz, Max Planck Institute for Intelligent Systems