How do reactive and planned behaviors interact in real time? How are sequences of such behaviors released at appropriate times during autonomous navigation to realize valued goals? Controllers for both animals and mobile robots, or animats, need reactive mechanisms for exploration, and learned plans to reach goal objects once an environment becomes familiar. The SOVEREIGN (Self-Organizing, Visi...

We consider visibility graphs involving bars and arcs in which lines of sight can pass through at most k objects. We prove a new edge bound for arc k-visibility graphs, provide maximal constructions for arc visibility graphs and semi-arc k-visibility graphs, and give a complete characterization of semi-arc visibility graphs. We further show that the family of arc i-visibility graphs is never co...

We define a natural class of graphs by generalizing prior notions of visibility, allowing the representing regions and sightlines to be arbitrary. We consider mainly the case of compact connected representing regions, proving two results giving necessary properties of visibility graphs, and giving some examples of classes of graphs that can be so represented. Finally, we give some applications ...

In this paper, we are concerned with computing and maintaining the exact visibility polygon V (q) of a moving point observer q in planar scenes represented by a polygon with holes with complexity of n. We propose an algorithm that applies and computes each change to V (q) in constant time as q moves to a new neighboring position. In fact, in our method changes to V (q), as the observer q moves,...

A sensor based navigation algorithm for a mobile robot which assures a convergence property is proposed when the robot is navigated from a given start position to a goal position while avoiding moving and fixed obstacles. This algorithm guides the robot toward the goal by using its sensor information in an unknown environment. Conventional sensor based navigation algorithms such as Bug algorith...

Let S be a set of horizontal line segments, or bars, in the plane. We say that G is a bar visibility graph, and S its bar visibility representation, if there exists a one-to-one correspondence between vertices of G and bars in S, such that there is an edge between two vertices in G if and only if there exists an unobstructed vertical line of sight between their corresponding bars. If bars are a...

Autonomous robot An autonomous robot is a robot that can perform tasks in unstructured environments with minimal human guidance. Planned path A planned path is a pre-determined, obstacle-free, trajectory that a robot can follow to reach its goal position from its starting position. Complete path planner A complete path planner is an algorithm that is guaranteed to find a path, if one exists. De...