Practical Distance-Based Multi-robot Formation Control Using Low-Cost Ultrasonic Source Tracker

Abstract

This paper addresses a communication-free formation control problem for multi-robot applications. To eliminate the formation control errors of the existing nonlinear control schemes, the linear quadratic(LQ) servo technique is applied to a state-space equation which describes the relative motion of a follower robot with respect to a leader in line-of-sight(LOS) frame. Under the assumption that the leader is equipped with an omni-directional ultrasonic transmitter, a gimbaled source tracker is designed to obtain range and bearing measurements. Thus, it enables us to implement the formation controller without any data links. By exploiting the LQ servo structure, our approach not only guarantees the robustness against unmodeled robot dynamics or unknown disturbances, but also makes quantitative analysis on stability margin possible. The superior formation control performance of the proposed method is verified through experiments.