Limit cycles can occur when navigating unmanned ground vehicles (UGVs) using behavior-based or other reactive algorithms. Limit cycles occur when the robot is navigating towards the goal but enters an enclosure that has its opening in a direction opposite to the goal. The robot then becomes effectively trapped in the enclosure. This thesis presents a solution to the limit cycle problem for robot navigation in very cluttered environments, for example dense forests. These type of environments offer a challenge due to the diversity of shapes and sizes of deadlocks that are likely to appear. A simple deliberative algorithm for detecting and retracting from limit cycles is described. The algorithm uses spatial memory to detect the limit cycle. Once the limit cycle has been detected, a labeling operator is applied to a local map so that the obstacles that form the boundary of the deadlock enclosure are identified. Subsequently, the robot is directed outside the enclosure using a behavior based control system. Once it exits this region, the deadlocked area is designated as off-limits by means of a virtual wall. Finally, the robotic vehicle proceeds to its original target avoiding the virtual wall and the different obstacles that are found on its way. Simulation and experimental results demonstrate the effectiveness of the proposed method. / A Thesis Submitted to the Department of Mechanical Engineering in Partial FulfiLlment of the Requirements for the Degree of Master of Science. / Summer Semester, 2006. / June 6, 2006. / Limit Cycle, Local Minima, Behavior Robotics, Navigation Algorithms, Fuzzy Behavior Systems / Includes bibliographical references. / Emmanuel G. Collins, Jr., Professor Directing Thesis; Cesar Luongo, Outside Committee Member; David Cartes, Committee Member; Carl Moore, Committee Member.
| Identifer | oai:union.ndltd.org:fsu.edu/oai:fsu.digital.flvc.org:fsu_180553 |
| Contributors | Ordonez, Camilo (authoraut), Collins, Emmanuel G. (professor directing thesis), Luongo, Cesar (outside committee member), Cartes, David (committee member), Moore, Carl (committee member), Department of Mechanical Engineering (degree granting department), Florida State University (degree granting institution) |
| Publisher | Florida State University, Florida State University |
| Source Sets | Florida State University |
| Language | English, English |
| Detected Language | English |
| Type | Text, text |
| Format | 1 online resource, computer, application/pdf |
| Rights | This Item is protected by copyright and/or related rights. You are free to use this Item in any way that is permitted by the copyright and related rights legislation that applies to your use. For other uses you need to obtain permission from the rights-holder(s). The copyright in theses and dissertations completed at Florida State University is held by the students who author them. |
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