Distributed algorithms for multi robot rendezvous and coverage

The advancements in mobile robotics have made the low-cost and robust robots to navigate in complex environments and perform complex tasks. To execute a task efficiently with a group of robots, it is significant to design efficient robot strategies. In this thesis, the rendezvous search problem which is a fundamental problem in robotics is studied. The rendezvous search problem considers how the robots that are located in different positions in an environment can meet as quickly as possible. Search and rescue tasks are one of the important applications of this problem, rescuers (robots) can search for the victims or the survivors who are in dangerous situations such as disasters and explosions. When there are no satellite receivers, the power is limited and the geometry of the environment is inconvenient, the robots should be in the line of sight of each other to communicate successfully. In such situations, robots should be close to each other to communicate, so they need to rendezvous. Other applications of rendezvous search for such situations are network formation and multi robot exploration and mapping. In this thesis, the symmetric version of this problem is studied. In this version, each robot executes the same strategy, because they do not have a chance to meet in advance to decide on the strategies they would perform during the search. First, the rendezvous search problem is studied on the line for two identical robots that do not know the initial distance to each other and a symmetric rendezvous strategy is presented. Both the cases that is when the robots move synchronously in which they start searching at the same time and when the robots move asynchronously in which they start searching at different times are considered. Second, the same problem is studied in planar environments with and without obstacles with two and multiple robots. A symmetric rendezvous strategy for these environments is studied. In this part, an algorithm for the exploration of an environment with obstacles by a robot is also provided. The performances of the symmetric rendezvous strategies are theoretically analyzed and their performances are also evaluated in simulations and experiments. Keywords: Linear search problem, rendezvous search, symmetric rendezvous, robot rendezvous, robot exploration and coverage.