state_exchanger

This package exchanges behavioral states between multiple cyber physical systems (CPSs) in a swarm.

Dependencies

This package depends on the following message definitions: * smach_msgs * cpswarm_msgs

The communication between CPSs is based on the CPSwarm Communication Library.

The state that is exchanged is read from a SMACH state machine.

Further required packages are: * roscpp

Execution

Run the launch file

roslaunch state_exchanger state_exchanger.launch

to launch the state_exchanger node.

The launch file can be configured with following parameters: * id (integer, default: 1) The identifier (ID) of the CPS used for name spacing in simulation. * output (string, default: screen) Whether to show the program output (screen) or to write it to a log file (log).

In the param subdirectory there is the parameter file state_exchanger.yaml that allows to configure the behavior of the state_exchanger node.

Nodes

state_exchanger

The state_exchanger node publishes behavioral states of this CPS to the rest of the swarm and publishes the state received from the other swarm members locally. The state is taken from a locally running SMACH state machine. If the CPS is in multiple states, only the first one is considered.

Subscribed Topics

• smach_server/smach/container_status (smach_msgs/SmachContainerStatus) The current state of this CPS.
• bridge/events/state (cpswarm_msgs/StateEvent) The current state of another CPS. Messages are exchanged between CPSs using the CPSwarm Communication Library.

Published Topics

• state (cpswarm_msgs/StateEvent) The current state of this CPS that is forwarded by the CPSwarm Communication Library to the other swarm members.
• swarm_state (cpswarm_msgs/ArrayOfStates) The states of the other swarm members received through the CPSwarm Communication Library.

Parameters

• ~loop_rate (real, default: 1.5) The frequency in Hz at which to run the control loops.
• ~queue_size (integer, default: 10) The size of the message queue used for publishing and subscribing to topics.
• ~timeout (real, default: 20.0) The time in seconds after which another CPS is considered to have left the swarm.
• ~sm_path (string, default: /SM_TOP) The path of the smach state machine whose state shall be exchanged.

Code API

state_exchanger package code API documentation

Changelog for package state_exchanger

1.1.0 (2019-10-31)

• Initial release of state_exchanger
• Contributors: Micha Sende