SMACH for multi-agent systems

[AlexisTM]

I have a multi-agent application which is like a big state machine: Parcel sorting.

To deliver parcels, we are currently using Actionlib to provide tasks to the UGVs, and the tasks are defined by a simple state machine.

I just bumped into SMACH and wonder if it is suitable for multi-agent systems like my application. For one UGV, it would be super simple to use SMACH, but I do not see how I could use it for multiple agents.

The state machine for each UGVs looks like:

START
   * INIT
INIT
   * GET_PARCEL
GET_PARCEL
   * when parcel_put: SCAN_PARCEL
SCAN_PARCEL
   * when parcel_scanned DELIVER_PARCEL
DELIVER_PARCEL
   * when parcel_removed: GET_PARCEL
   * if timeout: EMERGENCY_GATE
EMERGENCY_GATE
   * when parcel_removed: GET_PARCEL

[LoyVanBeek]

Each UGV should be able to run it's own state machine. Even if all state machines are running on the same roscore, as long as they run in different namespaces I think this should be fine.