Controle de formações flexíveis de robôs móveis com desvio de obstáculos

Abstract

This work presents a multi-layer scheme to control formations of n 3 mobile robots, including a strategy for obstacle avoidance. The proposed controller is able to guide the robots to compose a desired formation (position control) and/or track a desired trajectory (trajectory tracking control). The obstacle deviation strategy is based on virtual forces, generated as a function of the robot-obstacle distance, which are considered to change the linear and angular velocities of the individual robots grouped in a formation. Such strategy is implemented in each robot in the formation individually, whereas the proposed controller is applicable to clusters of three robots, i.e., to triangular formations. Also, a proof of the stability of the closed-loop control system is presented, based on the theory of Lyapunov, including the saturation of the magnitude of the control signals, to avoid the saturation of the actuators. Finally, simulated and experimental results for distinct formations of unicycle-like mobile robots are presented, demonstrating that the proposed control scheme is effective not only in terms of ensuring that the robots reach and/or maintain a desired formation, but also in terms of avoiding obstacles while navigating in the workspace.