Robust leader-follower formation control of autonomous vehicles with unknown leader velocities

We address the problem of formation-tracking control of velocity-controlled unicycles in a leader-follower configuration, both with known and unknown leader velocities. The controller design is based on relative measurements: distances and line-of-sight angles. This type of measurements are provided by onboard sensors rather than global positioning systems. We assume that a virtual leader generates a desired reference trajectory for the whole swarm, that is once continuously differentiable, bounded and with bounded derivative. We propose two controllers, one for which it is assumed that the leader velocities are known and one in which they are unknown.

I. Introduction

The formation control problem of nonholonomic vehicles consists in controlling a group of robots to perform a desired formation around a given point or follow a trajectory [1], [2]. Such problem has been addressed in the literature via time-varying controls [3] [4], or time-invariant discontinuous controls [5].