Robust box-pushing task of autonomous mobile robots using the watcher-pusher structure

In this paper, we propose an algorithm to solve the box-pushing problem using two mobile robots. One robot is assigned to be the watcher and the other the pusher to accomplish box-pushing task in an environment with obstacles. The watcher moves to the goal position and sends information about the environment to the pusher, which pushes the box to the goal point. Using the watcher-pusher structure, we present a robust task algorithm that can accomplish the box-pushing task even if several faults occur to the system. If a fault is detected during the execution of four classified sub-tasks, a fault-tolerant task corresponding to each fault is executed. We show that two mobile robots with the watcher-pusher structure can successfully complete the box pushing task, through collaboration by employing obstacle-avoidance path planning and implementing fault-tolerance sub-routines. Experiments on real mobile robots are conducted to validate the proposed methodology.