Overview

world_db_core provides the basic functionality for creating and maintaining a persistent belief state. It uses an interface to rosbag to record low-level sensor data and creates an index in an SQLite database. Plugins have access to the database through model_database and can store their state for later calls. Further, plugins have access to the recorded bag files. They can either directly play back sensor data or get instances of type rosbag::MessageInstance to publish or process them on their own.

Configuration

The basic configuration is done via ros parameters. Plugin parameters normally live in sub-namespaces of world_db_core.

Parameters

• The directory in which the database is created/read and where bag files are put.

• The plugins to load on startup. This parameter contains a list of lists. Every sublist has length 2 with the plugin name as the first element and the namespace of the plugin as the second element.

• The list of topics to record. world_db_core supports throttled recording, i.e. it records messages at most at the specified rate. This parameter is a list of lists with every sublist containing exactly two parameters. The topic to record is the first element and the minimum time difference between two messages as the second parameter.

Example Configuration

This yaml snippet configures world_db_core to record the tilting laser, tf and the narrow stereo. It loads four plugins and parameterizes them. For the parameters of the plugins, please read the documentation on world_db_detector_lib and tf_recorder_plugin.

      base_directory: /removable/lorenz/planes
      topics:
        - ["/tf", 0.05]
        - ["/narrow_stereo_textured/points2", 2.0]
        - ["/tilt_scan", 0.0]
      plugins:
        - ["world_db_plane_detector/PlaneDetector", "plane_detector"]
        - ["world_db_plane_detector/TableDetector", "table_detector"]
        - ["world_db_table_highlevel/TableHighlevel", "table_highlevel"]
        - ["tf_recorder_plugin/TFRecorder", "tf_recorder"]
      tf_recorder:
        record_frequency: 20.0
      plane_detector:
        detector_action: "/plane_detector/detect"
        detector_input_topic: "/plane_detector/input"
        detector_name: "/plane_detector"
        robot_base_frame: "/base_link"
        recorded_input_topic: "/narrow_stereo_textured/points2"
      table_detector:
        source_plugin_name: "plane_detector"
      table_highlevel:
        detector_action: "/highlevel_detector/highlevel_detection"
        detector_input_topic: "/highlevel_detector/input"
        detector_name: "/highlevel_detector"
        robot_base_frame: "/base_link"
        source_plugin_name: "table_detector"
        playback_rate: 10