Getting started with the kDB ROS Server
WARNING auKsys/5 has been released as stable, but this documentation has not been fully updated with changes since auKsys/4. In case of questions or mistakes, you can use the support project.
The kDB ROS Server is the main interface between a running ROS system and the knowledge database (kDB).
Introduction
The ros_kdb package provide a server with the following functionnalities:
- recording of topics
- querying services (RDF Graph, Altitude…)
- automatic synchronisation of RDF Graph between agents
- data transfert between agents
Running
The kDB ROS server is started with:
ros2 run ros_kdb kdb_server
This will give access to all the functionnalities of the server, the database will be stored in $HOME/.ros_kdb/default
. If a namespace is provided when starting the robot, with:
ros2 run ros_kdb kdb_server __ns:=/robot_ns
In this case, the database is stored in $HOME/.ros_kdb/robot_ns
.
Services/Topics
Base Knowledge
Many of the functionnalities of ros_kdb
requires a base knoweldge, which is data stored in a directories, containing DEM, RDF Graph… Base knowledge can also be defined as python or ruby scripts.
Base knowledge directories can be added wit a krQL query, for instance:
ros2 service call /robot_ns/kdb_server/krql_query ros_kdb_interfaces/srv/QueryDatabase "queries: [{query: 'REGISTER BASE KNOWLEDGE directory: \"/path/to/directory\"'}]"
Topic Recording
SQL Query
SPARQL Query
Altitude Query
The kdb_server/get_altitude
service allows to access the altitude given the coordinate. This service is only working if you have loaded a digital elevation map of the area, for instance, using the base knowledge functionnality.
ros2 service call /robot_ns/kdb_server/get_altitude ros_kdb_interfaces/srv/GetAltitude "{latitude: 58.494844, longitude: 15.102244, srid: 4326}"
Graph Synchronisation
Dataset Transfert
Tutorials
The following topics are covered for ROS tutorials:
- Getting Started with ROS this tutorial covers how to start and query a store using ROS.
- Querying with ROS tutorial covers more information about how to query the database using ROS.
- RDF Graph Synchronisation covers how to synchronise RDF Graphs between agents.