Environment and Localization
Accurate and precise localization - knowledge of each agent’s position and heading in relation to the world frame - is critical for each agent to successfully calculate and navigate to its destination. To do this, we executed ground-truth localization.
Each Neato is outfitted with an upwards-facing camera to track ceiling-mounted fiducials. Six unique fiducials are placed throughout the ~10' by ~14' arena. The package ar_tools calculates the bot's position and heading by comparing the seen fiducial a library of fiducials.
Top view shot of environment with fiducials overlaid.
ar_tools was originally set up for a single bot. Our fork reconciles individual agents' coordinate frame tranforms into a single world reference frame, called STAR.
Modified (current) TF frame.
Each Neato's camera is slightly different, in terms of both characterization and mounting. These differences, although seemingly minute, greatly affect localization quality.
Before we integrated AR localization of robots in the world frame, we were using the odom frame, computed based on wheel odometry. We had to start all the robots in a line and we were not able to start them in different location.