Building a Behavior Tree in JSON

The mr_bt project allows users to define behavior trees as JSON files. Each node in the behavior tree is a JSON dictionary object, for example:

{
    "name":"goal_pid",
    "type":"Multitasker",
    "children":[

        {
            "name":"Calculate angular velocity necessary to face towards the position",
            "type":"PathCorrection",
            "correction_var_name":"angular_goal_pid",
            "goal_value_var_name":"goal_rotation",
            "current_value_var_name":"rotation",
            "max_vel":1.5
          },
          {
            "name":"Calculate linear velocity to get to position",
            "type":"PathCorrection",
            "correction_var_name":"linear_goal_pid",
            "goal_value_var_name":"dist",
            "current_value_var_name":"dummy_current_value",
            "max_vel":0.1,
            "offset":0
          }
    ],
    "blackboard":{
        "angular_goal_pid":null,
        "linear_goal_pid":null,
        "dummy_current_value":0,
        "dist":null
    },
    "blackbox":true
}

Folder structure

When building a new project create a new folder with the name of your project in mr_bt/src/tree_jsons.

Each behavior tree project must have a root JSON file named root.json. This file will define the root node of your behavior tree and must be unique in your project folder. For example if you want to make a new project named my_new_bt_project, your folder structure should look something like this:

mr_bt/src/tree_jsons/
  my_new_bt_project/
    root.json
    action1.json
    action2.json