A systematic implementation of role assignment in multi robots using leader follower approach: Analytical and experimental evaluation

Robots moving in an unknown environment are made to face many obstacles while navigating in a planned or unplanned trajectory to reach their destination. But, no information is available regarding the failure of leader robot of a group in both unknown and uncertain environments and the subsequent course of action by the follower robots. The leader robot might fail due to internal and external disturbances while navigating in an unknown environment where the robots don´t have any prior information about the environment. If the leader fails, one of the follower robots within the group can be assigned as a new leader so as to accomplish the planned trajectory. A novel Role Assignment (RA) scheme for identifying a new leader robot among the group of robots, in case of failure of a previously assigned leader robot, is presented. This scheme combines techniques such as Leader Follower Approach (LFA), Fault Tree Analysis (FTA) with fuzzy triangles, virtual robot experimentation platform; and a dynamic RA algorithm. Distance and orientation errors occur as the robots traverse in this environment. To minimize these errors, a Dual Mode Decoupling Disturbance Observer (DMDDO) is developed which exponentially stabilizes the tracking errors. This observer shows robustness to various disturbances. The experimental work investigates on this RA scheme developed for multi robots. Further, the robot team considered for this work consists of one leader robot and three followers. The robots, fixed with multi sensors and the common driver have been integrated with a Data Acquisition System (DAQ). The optimal time taken to reach the goal with RA has been determined experimentally.