Formation control of nonholonomic mobile robots with inaccurate global positions and velocities

In this article, leader-following formation control is investigated for nonholonomic mobile robots with inaccurate measurements of global positions and velocities. In many existing results, the leader robot's velocities are assumed to be precisely measured and transmitted to follower robots, and unmodeled parts of the kinematic model caused by inaccurate global position are often ignored. First, an error-based extended state observer (EBESO) for each robot is designed to counteract influence of the inaccurate global positions and velocities in real time. Then, an EBESO-based formation controller without the leader robot's velocities is proposed to guarantee the accurate formation tracking performances. Furthermore, both convergence of the EBESO and stability analysis of the closed-loop error system are provided, respectively. The superiority of the proposed method is verified and illustrated by experiments.