Path Planning and People Avoidance

Lewis uses standard mobile robot path-planning algorithms to plan trajectories to all of the candidate picture-taking positions. The candidate positions are currently chosen at random, with a greater chance of moving to a place the robot has not been recently or where there are the most people. Lewis can opportunistically change its mind about which picture to pursue. People are not static and tend to move about. This means that shots identified in the past will not be valid forever. A time decay mechanism is implemented that favors more recently added potential shots, culling out those that probably no longer exist.

An important component of path planning is staying within the bounds of the installation. Lewis uses internal odometry and a visual landmark to determine its exact location, which is then compared to a supplied map (the rectangular area of the room). The landmarks are lit, colored spheres, mounted on top of a post. By using the size, angular, and apparent proportions of the two colors, Lewis can reliably determine its position in the installation.