Vision-based Leader-Follower Mobile Robots for Cooperative Object Handling

This paper has addressed the problem of transporting a long object from a given starting location to an end location using leader-follower robot formation in an environment filled with obstacles. Only the leader robot has the authority to make decisions. It possesses the main controller and is capable of navigating through an unknown environment using the data provided by on-board sensors. In the proposed system, a vision-based feedback method is combined with an explicit control method that oversights the virtual trailer between the leader and the follower. The parameters required to maintain a constant distance between the two robots are computed by the leader and transmitted to the follower directly. A fiducial marker is mounted on the front of the follower robot and is captured by a camera attached to the leader robot. Information exchanging methods based only on impedance control can be expensive because of the need of high-level controllers and force/torque sensors for both robots. Furthermore, the visual response scheme adds robustness to the system by reducing the limitations of sole explicit control methods. The proposed control algorithm is implemented on the developed mobile robots. The experimental results suggest that the vision-based feedback method is more effective in cooperate object carrying tasks.