The INL has developed a tracking behavior that allows the robot to track and follow an object specified by the operator with the camera. The tracking behavior is not limited to visual tracking, but can be used with any tracking system including a thermal imaging system for tracking human heat signatures. The operator can specify an object to be tracked within the video display by pressing the pursuit button on the interface and then manipulating the camera view so that the object to be tracked is within a bounding box. The camera will then track the object based on a combination of edge detection, motion tracking, and color blob tracking. The camera can track the motion of the target independently from the motion of the robot, which allows the robot to follow the optimal path around obstacles even if this path at first takes the robot in the opposite direction as the target.
The key to high-speed chase capabilities is effectively blending the obstacle avoidance, reactive path planning and pursuit behaviors. A behavior called “maneuver” uses fuzzy logic rules to select the best path when these behaviors conflict. This gives the robot the ability to quickly change direction in tight quarters while heading towards a moving goal.