Formation control strategies for emulation of field covering

Abstract

This work aims at investigating the subject of formation control, i.e. controlling a group of mobile robots to make them form a specific geometric pattern and, additionally, to have them maintain this pattern while moving. In view of this two-fold scope, we have conducted experiments using mobile robots equipped with an on-board camera that, by means of a stepper motor, can rotate over 360°. Within this setting, the rotatable camera functions as a decentralized sensor that gives the position and orientation of the follower with respect to the leader. Given the lack of communication between the robots, we use a combination of PID-PI cascade control and a PI feedback loop to have them form and sustain a triangular leader-follower formation. As a way of illustrating the concept, we will discuss a practical application whereby a formation of combine harvester machines is used to harvest crops.