Distributed switching control to achieve resilience to deep fades in leader-follower nonholonomic systems

Abstract

Leader-follower formation control is a widely used distributed control strategy that often needs systems to exchange information over a wireless radio communication network to coordinate their formations. These wireless networks are subject to deep fades, where a severe drop in the quality of the communication link occurs. Such deep fades may significantly impact the formation's performance and stability, and cause unexpected safety problems. In many applications, however, the variation in channel state is a function of the system's kinematic states. This suggests that channel state information can be used as a feedback signal to recover the performance loss caused by a deep fade. Assuming an exponentially bursty channel model, this paper proposes a distributed switching scheme under which a string of leader-follower nonholonomic system is almost surely practical stable in the presence of deep fades. Sufficient conditions are derived for each vehicle in the leader follower chain to decide which controller is placed in the feedback loop to assure almost sure practical stability. Simulation results are used to illustrate the main findings in the paper.