ex05_behavior_trees

ex05_behavior_trees

!! unfinished !! Help is appreciated.

Deliberation Layer

Action clients are normally implemented inside of high level robot control software, sometimes referred to as deliberation layer. The two most well-known concepts of deliberation are state machines and behavior trees. Most of the states in a state machine are basically action clients that are calling and monitoring actions provided by the robot using a certain set of parameters, the states are connected via transitions:

However, the current trend in the ROS community is to use behavior trees. For behavior trees the core concept stays the same. Nodes in a behavior tree trigger and monitor the actions the robot provides. More to this later. We will start with creating own actions and action server.

BehaviorTree.CPP

First Behavior Tree

Splitted:

• ex05_bt_plugins: only for bt-nodes as plugins for the behavior tree library
• ex05_behavior_tree: Loading the nodes and execute a behavior tree

Monitor using Groot

https://github.com/BehaviorTree/Groot.git

Editing using Groot

TODO: Create a new behavior tree using Groot editor.

• Load the nodes from ex05_bt_plugins
• Create a behavior tree
• Put it into a new node and monitor it

Blackboard

TODO: Trigger own wait for pose action from a new behavior tree node (bt-node). Write the result in a blackboard entry

Caution! Bt-nodes are not the same as ROS-nodes!

Use nav2 actions

TODO:

• Load the Nav2 plugins into Groot editor
• Load our plugins into the Groot editor
• Create a BT that connects the results of our wait-for-pose bt-node with a Nav2 compute path bt-node
• Try to create a tree that does the following:
  • Wait for pose
  • Compute path
  • Follow path