Constructing Low-Cost Swarm Robots That March in Column Formation 

On-Board Evolutionary Algorithm and Off-Line Rule Discovery for Column Formation in Swarm Robotics

“…Quite a few approaches have been proposed to sidestep the reality gap, through, e.g., closing the gap [3] or using dimensionality reduction [4]. On the other hand, the presented study resumes an earlier work, devoted to building low-cost robots [5]: there is no reliable simulator available for these robots, and it makes sense to design a training process relevant to such simulator-less experimental frameworks.…”

“…We believe that details of our physical robots are important as we tackle an on-board optimization of the controller, Resuming an earlier work [5], each robot ( Fig. 1) is equipped with 5 infrared (IR) proximity sensors, a camera, a lowcost micro-processing unit (MPU), and a LED light signaling its presence to the other robots.…”

“…The robot locomotion uses two wheels and a supporting ball, enforcing a sufficient robustness of the robot (in contrast to our former use of two caterpillar [5]). The driving system consists of two motors each of which is connected to a wheel, a controlling circuit, a gear box, and the supporting ball.…”

“…Note that we use a simplified version of the controllers used in [5], but we evolve it using the (1+1) ROAA [7], which we explain in the next section, during the experiments.…”

“…On the one hand, it takes much longer than using the simulator; 12 controller architectures have been considered in [5], and training each one of them in order to select the best one takes a large amount of time. On the other hand, in-situ training is physically demanding for the robots and might entail physical hazards.…”