Paper Title
Laser-Based Modeling of Unknown Environment by Group of Autonomous Homogeneous Cooperating Mobile Robots

Abstract
In this paper, a new multi-robot exploration algorithm is designed and tested to model unknown environments with least possible time, energy and computations. Each robot is equipped with a 2D laser scanner as an exploration sensor. The main advantage of the proposed algorithm is that it directs robots towards the obstacles located at the edges between explored and unexplored areas, such obstacles are called frontier obstacles. By contrast, in most of the previously published works all the edges lying on the borderline between explored and unexplored areas (frontier cells) are nominated as robot future locations. The number of “frontier obstacles” is much less than the number of frontier obstacles. As a result, it is expected that much less computational capabilities are required by the proposed algorithm. Each robot is directed to the closest frontier obstacle where a complete laser scan is performed. Furthermore, to decrease the probability that same part of the environment is scanned by more than one robot, the new algorithm is integrated with an overlap control option. Such an option is effective to decrease the overall travelled distance (i.e. energy). Finally, for further improvement, the algorithm is evaluated when each obstacle is isolated by a virtual thin barrier which robots can’t penetrate. Such a barrier, called safety barrier, is beneficial to avoid obstructing the laser rays by the very close or adjacent obstacles. As a result, the exploration time has been significantly decreased. The proposed algorithm with the extensions and improvements mentioned above, was intensively tested with outdoor and indoor environments and the results are very promising. Keywords - Robot, Laser Scanner, Exploration Algorithm, Unknown Environment.