Nodes, events and actions

Behaviours have two kinds of nodes in the behaviour graphs.

1. Events are spontaneous events that happen in the system. In robotics normally these are called sensors.
2. Actions are the actions to perform in response of some event. In robotics they are called actuators.

Chains are the paths that start at an event, and join different actions to perform sequentially. If there is a split in the path the guards will decide which path to follow, or if several apply or no guards, one path will be chosen at random.

See example.